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Corvette Maintenance

If you are having problems with your corvette, and the dealer can't help, try calling one of the self-professed VetteNet experts about your problem.

Check out these step-by-step Vette restoration projects!

Tom Veselenak's '65 roadster restoration.
Phil Garrett's '63 roadster restoration.

Powertrain

ALDL info gleaned from various places.
Propylene glycol coolant won't void your warranty.
Cooling that hot engine.
Hard starting problem on '95 vettes only.
Fuel injectors for TPI late models.
Replacing valve seals
Some words on replacing a turbo 350/400 with a 700R4
Disabling CAGS
Some words about K&N filters
Getting to the sparkplugs on an LT1

Engine Accessories

Displaying A/C error codes on the A/C display

Suspension

4 Wheel Alignment for vettes (and other cars).
Brake Pad Comparison:
Suspension summary for late model vettes.

Electrical

Removing the battery on late-models:

Body

Removing and Installing the Body of a C1
Meguires products: Explanation and application
Reinforcing the cargo area of your midyear/shark
Touching up scratches in your paint

Interior

Repairing those digital IP clusters
Change the tuning increment of Delco Radios (for Vettes outside the US)
Repairing the clock in your midyear
Repairing late model inflatable seats
Late model window regulators
Repairing old corvette radios

Tools

Choosing a good Dial Indicator

VetteNet Experts

Some people on the VetteNet have volunteered themselves as having expertise in some area of Corvette maintenance or modifications:

Shark Vacuum accessories: Frank C Prow
From ubc-cs!news-server.csri.toronto.edu!rpi!think.com!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!ira.uka.de!fauern!faui43.informatik.uni-erlangen.de!orscholz Mon Jan 6 11:05:45 PST 1992 Article: 30417 of rec.autos.tech Newsgroups: rec.autos.tech Path: ubc-cs!news-server.csri.toronto.edu!rpi!think.com!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!ira.uka.de!fauern!faui43.informatik.uni-erlangen.de!orscholz From: orscholz@immd4.informatik.uni-erlangen.de (Oliver Scholz) Subject: Re: GM's ALDL info Message-ID: <1992Jan5.084232.22926@informatik.uni-erlangen.de> Organization: CSD., University of Erlangen, Germany References: <1992Jan3.192410.12029@informatik.uni-erlangen.de> <1992Jan4.190655.26721@bnlux1.bnl.gov> Date: Sun, 5 Jan 1992 08:42:32 GMT Lines: 33 Ven Polychronakos writes: >Could you post a summary of the replies you got? >Thanks, Ven Considering the interest in the information, it think a summary is justified. Here's what I know: The ALDL uses a TTL level output (1=H=5V, 0=L=0V) with 8192 Baud. A word consists of 10 Bits, the startbit (L), 8 data bits (LSB first) and one stop bit (H). The line is idle high. The ECM sends packets that look like this: 1 byte device code 1 byte: 85+N (N being the length of the data part of the packet) N data bytes 1 byte checksum between two packets the line goes idle (H) for at least 10 bit times. Information still missing includes: A list of device codes, the interpretation of the data bytes and how to compute the checksum (which I probably could find out myself... I guess it's just adding up the data part of the package. So, once again, if anyone has any further information, please let me know (or better yet, post to the net. I know a *bunch* of people is interested in this!) -Oliver ---------------------------------------------------------------------------- This is a little misleading, from what I've seen on the 8192 format. It may be correct for the ALDL data output in 10k mode. It should read: 1 Byte message ID 1 Byte Length (85 + 1 + N - The next byte counts too!) 1 Byte Mode Specifier ( Usually ranges from 0 to 7) Data bytes 1 Byte checksum (two's complement of sum of the previous bytes) > >Information still missing includes: A list of device codes, This is defined in the Cal section of the PROM, and can be anything from 0-255. The ones I've seen seem to like to use 0xF0, and it normally will be the same as the value of the heartbeat sent out in normal mode. Dig sdbartho@hwking.cca.rockwell.com ---------------------------------------------------------------------------- Thanks for posting this information. I had figured out (the hard way) the basic protocol but had (and still do) trouble interpreting what I was reading. At least now I can stop trying to decipher the checksums and device codes. So here is my minor, I'm afraid, contribution towards solving the puzzle. Below is a record of what the serial link on my '88 Celebrity (2.8L, v6,VIN W engine) tells me. Car at "PARK", engine idling. All digits hexadecimal. 0A 58 00 03 53 48 0A 58 00 03 61 3A 0A 58 00 03 6A 31 05 5F 00 00 00 3C 8C 39 62 01 EC 72 DA 0A 58 00 03 69 32 F0 55 BB The first line, for example, shows device code 0A (10 Decimal), 3bytes of data (58 hex=88 decimal, therefore 88-85=3), then the three bytes of data follow and ,finally, the checksum byte 48. By the way these three bytes are zero when ignition is ON but engine not running.This device code seems to be repeated 3 more times in the same record!? The device code 05 gives 10 bytes of data from which the only one I was able to figure out is the fifth one (8C= 140) which looks like the battery voltage, 14.0 V, when interpreted as tens of millivolts. When engine is not running it becomes about 12.0 V.Finally the device code F0 has zero data(55) and seems to be some sort of end-of-record marker (BB by the way is the checksum of F0 and 55). The checksum byte is the two's complement of the 8-bit sum of all bytes in a given packet (except the checksum itself) not only the data part. In plain english if you sum all bytes now including the checksum the eight least significant bits of this sum should be all zero. If anyone has more information on the contents of these packets, I would appreciate hearing it. Thanks in advance, Ven. --------------------------------------------------------------------------------- From ubc-cs!news-server.csri.toronto.edu!rpi!think.com!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!ira.uka.de!fauern!faui43.informatik.uni-erlangen.de!orscholz Mon Jan 6 11:05:45 PST 1992 Article: 30417 of rec.autos.tech Newsgroups: rec.autos.tech Path: ubc-cs!news-server.csri.toronto.edu!rpi!think.com!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!ira.uka.de!fauern!faui43.informatik.uni-erlangen.de!orscholz From: orscholz@immd4.informatik.uni-erlangen.de (Oliver Scholz) Subject: Re: GM's ALDL info Message-ID: <1992Jan5.084232.22926@informatik.uni-erlangen.de> Organization: CSD., University of Erlangen, Germany References: <1992Jan3.192410.12029@informatik.uni-erlangen.de> <1992Jan4.190655.26721@bnlux1.bnl.gov> Date: Sun, 5 Jan 1992 08:42:32 GMT Lines: 33 Ven Polychronakos writes: >Could you post a summary of the replies you got? >Thanks, Ven Considering the interest in the information, it think a summary is justified. Here's what I know: The ALDL uses a TTL level output (1=H=5V, 0=L=0V) with 8192 Baud. A word consists of 10 Bits, the startbit (L), 8 data bits (LSB first) and one stop bit (H). The line is idle high. The ECM sends packets that look like this: 1 byte device code 1 byte: 85+N (N being the length of the data part of the packet) N data bytes 1 byte checksum between two packets the line goes idle (H) for at least 10 bit times. Information still missing includes: A list of device codes, the interpretation of the data bytes and how to compute the checksum (which I probably could find out myself... I guess it's just adding up the data part of the package. So, once again, if anyone has any further information, please let me know (or better yet, post to the net. I know a *bunch* of people is interested in this!) -Oliver ---------------------------------------------------------------------------------- From ubc-cs!uw-beaver!zephyr.ens.tek.com!uunet!sun-barr!olivea!mintaka.lcs.mit.edu!hal.gnu.ai.mit.edu!lusky Mon Jan 6 11:07:17 PST 1992 Article: 30434 of rec.autos.tech Path: ubc-cs!uw-beaver!zephyr.ens.tek.com!uunet!sun-barr!olivea!mintaka.lcs.mit.edu!hal.gnu.ai.mit.edu!lusky From: lusky@hal.gnu.ai.mit.edu (Jonathan R. Lusky) Newsgroups: rec.autos.tech Subject: Re: GM's ALDL info Message-ID: <1992Jan6.073457.28814@mintaka.lcs.mit.edu> Date: 6 Jan 92 07:34:57 GMT References: <1992Jan4.190655.26721@bnlux1.bnl.gov> <1992Jan5.084232.22926@informatik.uni-erlangen.de> <1992Jan5.200542.2617@bnlux1.bnl.gov> Sender: news@mintaka.lcs.mit.edu Organization: ^ Lines: 22 Other values that the ECM sends back include manifold air temp and pressure, spark advance, rpm, throttle position, as well as several fuel injection related numbers (block learn multiplier is the only one that comes tomind at the moment). You might try finding someone with some type of scan tool so you know what values you are looking for. RPM, TPS, and MAP you should be able to pick out pretty easy. RPM will vary with rpm, TPS will vary with throttle position (even when engine isnot running), MAP will vary with vacuum (even when engine is not running... get an "assistant" to suck on a vacuum line connected to the MAPsensor while you sample packets). Jon Lusky lusky@gnu.ai.mit.edu > ------------------------------------------------------------------------------------- From ubc-cs!alberta!aunro!lll-winken!elroy.jpl.nasa.gov!usc!wupost!spool.mu.edu!umn.edu!math.fu-berlin.de!fauern!faui43.informatik.uni-erlangen.de!orscholz Mon Jan 6 11:07:49 PST 1992 Article: 30436 of rec.autos.tech Path: ubc-cs!alberta!aunro!lll-winken!elroy.jpl.nasa.gov!usc!wupost!spool.mu.edu!umn.edu!math.fu-berlin.de!fauern!faui43.informatik.uni-erlangen.de!orscholz From: orscholz@immd4.informatik.uni-erlangen.de (Oliver Scholz) Newsgroups: rec.autos.tech Subject: Re: GM's ALDL info Message-ID: <1992Jan6.081558.9803@informatik.uni-erlangen.de> Date: 6 Jan 92 08:15:58 GMT References: <1992Jan3.192410.12029@informatik.uni-erlangen.de> <1992Jan4.190655.26721@bnlux1.bnl.gov> <1992Jan5.084232.22926@informatik.uni-erlangen.de> <1992Jan5.200542.2617@bnlux1.bnl.gov> Organization: CSD., University of Erlangen, Germany Lines: 39 polychron@bnldag.ags.bnl.gov (Ven Polychronakos) writes: >0A 58 00 03 53 48 >0A 58 00 03 61 3A >0A 58 00 03 6A 31 >05 5F 00 00 00 3C 8C 39 62 01 EC 72 DA >0A 58 00 03 69 32 >F0 55 BB My guess would be that device code 0A is the engine RPM: in your example: 851, 865, 874 and 873. Could you verify that? >of data follow and ,finally, the checksum byte 48. By the way these >three bytes are zero when ignition is ON but engine not running.This Because the rpm is 0 ? >device code seems to be repeated 3 more times in the same record!? Because it's changing constantly ? >The device code 05 gives 10 bytes of data from which the only one >I was able to figure out is the fifth one (8C= 140) which looks like >the battery voltage, 14.0 V, when interpreted as tens of millivolts. Makes sense. That would be the sensory readings of A/D converters of some kind. The leading zeroes could be non-installed sensors, unused or reserved... Thanks for posting that information, I think it helped a lot! You might try disconnecting different sensors (Start with the TPS) and see which byte becomes zero (Or $FF). Try to force a trouble code (by disconnecting that sensor). Maybe the last packet is not the "End of Record" (which would be useless) but the stored trouble codes? (in your case: none) ?? Just a (more or less good) guess... -Oliver

From Hib Halverson, finspeed@aol.com

Couple of interesting developments on the service side from GM. First, GM has decided it's OK to use propylene glycol coolants. GM tells its dealers:

General Motors has been reviewing data supplied on the performance of propylene glycol engine coolant in GM vehicles. It is our conclusion that propylene glycol engine coolant will perform adequately under most vehicle operating conditions. As a result, propylene glycol (meeting performance specification GM1825M) may be used in GM vehicles and will not affect the warranty coverage.
Prior to adding propylene glycol engine coolant to the cooling system, all the existing (ethylene glycol) coolant must be removed. This can be acomplished either by utilizing water-based coolant flushing equipment or "waterless quick change" equipment available in the GMDE program. As with any coolant change procedure, be sure to thoroughly purge the heater core and block as well as the radiator before attempting to convert the system to propylene glycol coolant.
Freeze/boil point levels are different for propylene glycol than for ethylene glycol engine coolant. To accurately determine freeze/boil protection level, it is imperative that coolants not be mixed. Removing all the used coolant as previously discussed resolves this concern. Freeze protection of propylene glycol cannot be determined using a standar hydrometer. Rather a refractometer or test strip must be used.
Propylene glycol engine coolants my be recycled in the same manner as conventional ethylene glycol coolant. No adverse effects will be encountered if these coolants are mixed prior to recycling, however, the ratio of propylene glycol to etheylene glycol should be kept low to minimize the effects on freeze point measurement.

What these statements do not address is the effectiveness of propylene glycol as a coolant for use in high-performance applications. I'll have to research that. It is my opinion that the promoting of propylene glycol as an "environmentally friendly" coolant is mostly a myth. I feel that, strictly from an environmental standpoint (that is dumping the stuff over your backyard fence), ANY coolant used in a cooling system with a radiator made of copper and brass with soldered joints is harmful to the environment because of the lead that gets into the coolant from the solder. However, current model Corvettes do not use soldered copper/brass radiators. They use an aluminum/plastic design with a mechanically crimped seal.

Other than the lead contamination, etheylene glycol is not so bad. It biodegrades quickly.

Now, where etheylene glycol has a problem is toxicity, especially to domestic pets who like the taste. Supposedly, Rover or Socks don't really care for propylene glycol whereas they suck up big-time on ethylene glycol then keel over and become 'fly dogs" or "fly cats" after about a week.

Will I run out and pay a bunch of money for propylene glycol?
Nope.
Straight water and Red Line Water Wetter works just fine for me.

Here on some tips to keep your cool: 1) Flush your cooling system annually. A clean system has better heat transfer, both from the engine, and to the radiator. While you're are flushing, take a look in the radiator for tube blockage. 2) Flush bugs and other debris off of your A/C condensor with a garden hose. 3) Make sure your spoiler is in good shape. Corvettes are "bottom breathers", and the front spoiler is an integral part of the cooling system. 4) Turn your A/C on and open the hood. After 1 to 10 seconds or so, your electric fan should be spinning (once the A/C head pressure reaches about 190 psi), and a good volume of air should be ejected by the fan. Also check the fan shroud it is not cracked or broken (if it is, air will just recycle itself, rather than being pulled through the radiator. 5) Make sure your radiator baffles are in place. The radiator cannot do its job if air just travels around it. 6) Test the cooling system with a pressure checker for leaks. Also check the cap to be sure it does not relieve pressure below 15 psi. 7) Check your ignition timing. Retarded ignition timing will cause the engine to reject more heat. 8) Use premium fuel. Hot weather is not the time to economize on gasoline costs. Low octane will cause detonation, which increases engine heat rejection, and will cause knock sensors to retard ignition timing also increasing heat rejection. Low octane fuel can also result in preignition in a extreme situations (if that happens, you no longer have to worry about overheating, because you will have a hole in your piston-ouch!). 9) Check your belts to make sure they are in good shape. Water pump loads are low, so slippage is not usually a problem (the L98 even runs the pump on the back side of the poly-V belt, so that should give you an idea of how low it is), but belts are also more prone to failure in hot weather, thus leaving you stranded. Check the entire circumference of the belt, both inside and out. I recently has some delamination on my '89 on the top surface of the belt. 10) If you have a booster fan (Z51 models), and your coolant temperature is above 228 degrees, check and be sure the fan turns on. This fan does not automatically turn on with the air conditioning. It only comes on when it reaches the prescribed coolant temperature. I had a defective switch on my '89. 11) With the engine up to operating temperature, carefully run your hand over the radiator. The temperature of the core should be relatively even. If not, you probably have plugged tubes. 12) Use high gear! Contrary to all of the myths out there, the engine rejects the least amount of heat at a given load, if the engine is operated SLOWER, not faster. So if your engine is getting hot, DO NOT do what many people will tell you to do, which is run the engine faster (for which they have all sorts of arm chair "theories", ie. coolant circulating faster, fan running faster, etc.) Do the opposite! Get that car in the highest gear possible. This applies to cars with either electric or engine driven fans. Other things to watch for... a) Parking next to a building and idling the engine can cause your car to overheat in hot weather. The radiator air will recirculate from the exit of the radiator, and back into the inlet. In fact, this is how G.M. tests the "idling in traffic" condition. The car is parked up to a wall, and left idling. b) If you are driving down wind, especially in traffic, expect your car to run hotter. Again, you get radiator air recirculation. c) If you are towing a trailer in temperatures over 100 degrees, be prepared for overheating. G.M. does not certify cars for trailer towing over 100 degrees, even with a heavy duty radiator (which is not an option on Corvettes, except perhaps the earlier models). If you do not have the heavy duty radiator option, your maximum trailer towing temperature is even lower. d) Monitor your thermostat from time to time during cool weather. On a cool day, going down a gentle slope, after the engine has warmed up, operate the car at low engine load (but do not coast). The coolant temperature should fall to the thermostat opening temperature, or slightly below (188-195 F). Note: if you *coast* down a long hill, your coolant temperature can go quite a bit below thermostat opening temperature, and you really will not have a test. e) With electric fans, stop and go driving is not the problem it was with engine driven fans. If you have an engine driven fan, your best cooling speed is about 40 to 50 miles per hour (good air flow through the radiator, but not much heat rejection due to engine load). With electric fans, this is also usually the best speed, although some electric fan cars do just as well stopped completely, as they do moving. f) If your car starts getting hot, and you are driving fast, slow down to about 40 to 55 (speed limits permitting). You should see an almost immediate reduction in temperature. If not, there is an engine or cooling system malfunction. g) Turning off the A/C and turning on the heater is good advice if your engine is overheating. If you get to this point, though, there is something wrong with either the cooling system, or engine, and some sort of repair is in order. h) Check your coolant recovery tank to be sure it is topped off at the appropriate markings. i) If your engine overheats at over 60 miles per hour, your problem is not likely to be fan related. Most fans are free wheeling, like a wind mill at 60 miles per hour. There were only a few cars built with engine driven fans using VERY heavy duty clutches (the Turbo Trans Am being one of them) that would actually get cooling help from the fan over 60 miles per hour (and it sounded like an aircraft when it engaged!). j) One of the worst conditions for overheating on electric fan cars is brisk hill climbing up winding roads. The engine load is high, with frequent accelerating and braking, and speeds are too low to get good air flow through the radiator. Do not be surprised if you get high cooling system temperatures, even with fairly low ambients (80 F). The booster fan (Z51) was added to help compensate for this. Cars with engine driven fans can move much more air through the radiator, and generally do not experience this problem. k) Do not panic if your coolant temperature reaches 240 degrees. We didn't, while testing the cooling systems. We just kept driving with the A/C blowing full blast. This is the reason idiot lights are better for many drivers, so they will not panic while the system in still within normal operating ranges. Your overheat light does not even come on until 255, and boilover is about 262. The nice thing about a guage, is that you can monitor *changes* in coolant temperature. If the temperature is high (below 245) on a very hot day, but relatively stable, keep an eye on it, but enjoy the drive. (Between 245 and 255, take measures to lower the temperature, such as slowing down.) On the other hand, if it looks like the temperature is quickly soaring to the moon, you better pull over and shut the engine down. Stuck thermostats will give you this behavior. Hope this information helps a few of you during this hot season we are having. Michel Adams '89 Coupe 6-speed Z51 msadams@netcom.com

From Hib Halverson, finspeed@aol.com

GM told Chevrolet dealers of a weird starting problem with 95 Corvettes and it may affect any car built before VIN 10803 or about 2/27/95:

The starter will click, but the engine will not start. The starter will not spin. This usually happens in colder weather and the engine will start if the ignition is turned off then turned to "start" again. This condition is intermittant and may happen every time the engine is started cold or may happen only on rare occasions.
A low voltage specification in a microprocessor in the Central Control Module (CCM) may not allow the VATS relay to energize. This was corrected in production after VIN breakpoint S5110803, about February 27, 1995.
Before replacing the CCM, make sure that the battery is fully charged, that the starter is operating correctly and that the battery cables are properly tightened. This condition can be verified by the following procedure:

Let the vehicle sit overnight os the compenent are cold.
Try to start the vehicle. If the click/no start occurs, then turn the ignition off and immediately try to start the engine again. It should start. Turn the key off.
Wait at least one minute to allow the CCM to reset, then try again to restart.
If the click/no start happens again, the CCM is a fault and should be replaced with P/ N 16223622 following the directions in Section 8D of the Service Manual.

One thing about all this, if you THINK you have this problem, check your VIN first. If your car is later than 10803, you DO NOT have this problem and your starting problem is being caused by something else.

If your car is before 10803 and you have the symptoms, run the three step test discussed. It requires no special equipment. If you run the test and your car does not meet the criteria, your starting problem IS NOT the CCM. If it does meet the test, take it into the dealer you will probably get a warranty repair.

Replacing injectors on an '85 (possibly other years)

I know you're not gonna like this, but you can replace your whole set of eight injectors (24lb/hr injs. on an 85) for the price of one from GM. FORD motorsport 24# injectors for $169 a set! Pick up a copy, better yet, write down the phone number out of a page of a mustang magazine at your local store. ( You don't actually want to *BUY* a mustang mag... ;-) Look for 24# Ford MotorSport injectors. Price will range from $169 ~ $209 for a set!

I have an '85 and replaced mine after 35,000 miles and *wow* what a difference. The car had a much smoother idle! Turned my "lumpy" cam into a tame one.

Doug Bazarnic dougb@primenet.com

VetteNet How To: Replacing Smallblock Valve Stem Seals

Symptoms:

Recently I needed to replace the valve stem seals on my 1986 Corvette. The L98 engine had approximately 86K miles on the odometer. Some of the symptoms that lead me to performing the work appeared over the years. For some time I was experiencing a Service Engine Soon (SES) condition when cruising at 64-75mph. The SES light would come on and then go off. The error code was a code 45. The code 45 indicates a rich exhaust, and is triggered by the O2 sensor. I also noticed when changing the spark plugs that a couple of the plugs had black, oil deposits built up on them. The two plugs showing this were the ones closest to the firewall. This apparently is where the engine runs it hottest. Along with these symptoms, over the years, upon a cold start of the engine, there would be a noticeable cloud of blue smoke, that would clear once the car was running. Due to the smoke and rich exhaust, over time this condition would clog the main catalytic converter.

Tools Required:

Access to an air compressor.
Air compressor hose attachment that screws into the spark plug hole(s).
Torx bits.
Standard & metric sockets. >Valve spring compressor.
NOTE: Purchase the valve spring compressor type that fits over the spring and compresses the spring by turning a knob. DO NOT get the type that acts like a pry bar, as this one will not fit. There is not enough room to use the pry type on the L98 motor.
Valve seat oil deflectors (set of 16).
NOTE: These are optional, depending on if you need to adjust the valves with the motor running.

Parts Required:

Valve stem seal kit including seals for both Intake and Exhaust.
Replacement set of 2 valve cover gaskets.
Replacement set of 8 spark plugs (optional, but recommended).
EGR pipe clamp (obtain from GM dealer).

Approximate Costs:

Spark plug air compressor attachment: $6.00
Valve spring compressor: $20.00
Valve stem seal kit: $10.00
Valve seat oil deflectors (opt): $5.00
Spark plugs: Varies, $8.00 to $40.00
Rocker arm gasket kit: $8.00

Estimated Time to Perform the Work:

1 to 4 days. Figure on the car being out of service for several days.

Performing the Job:

Step 1:

Begin by removing the rocker arm covers. To remove the left side cover, you'll only need to loose the bolts holding the cover in place and gently work the cover off the head. To remove the right side, you need to remove the EGR piping. The EGR piping is the pipe wrapped in what looks like aluminum foil. It is connected below the distributor, with two torx bolts, and to a lower fitting by a circular clamp. Take care in removing the EGR pipe clamp, it may break. If it does, not to worry, an replacement can be obtained from your GM dealer for $2.67. I recommend replacing this clamp. Now remove the coolant intake hose to the plenum. Coolant will leak out, so be prepared to clean this up. Unscrew rocker arm cover nuts and gently remove the right cover.

Step 2:

Now that you have the rocker arm covers off, you can begin replacing the seals. Start by removing a spark plug from one side, leaving the others in, and screw in the air compressor attachment. WARNING: Do not tighten the attachment too much in the spark plug hole, because it's a pain to remove if you do!!! Supply air to the cylinder via the spark plug hole to hold the valve closed. Now remove the nut holding the rocker arm, doing both the intake and exhaust, and lift the rocker arm away. Note that the exhaust valve is the one that is lined up with the outlet to the exhaust manifold. The pushrods can remain in place. Position the valve spring compressor over the spring, and compress the spring enough to remove the retainer clips. There are two clips, and they are easily removed using a magnet once the spring is compressed. Remove the retainer and spring. Now you are ready to replace the two seals. There will be a small o-ring seal, and either a rubber "stopper" looking seal, or rubber cap seal, depending on which valve you are doing, the intake or exhaust.

Step 3:

Once the seals are replaced, you will replace the spring, still in the valve spring compressor, onto to the valve. Replace the valve spring retainers and clips. Once both intake and exhaust are done for that valve, you can release the air pressure from the cylinder and replace the spark plug with the new one. Replace the valve tappet and loosely tighten the bolt. Repeat these steps for each valve until completed.

Step 4:

Adjust the valves. Refer to a manual on adjusting the valves. There are two ways to do this. One w/the engine running the other not. If you decided to do w/the engine running, then you'll need the oil deflectors.

Step 5:

After the valves have been adjusted, replace the rocker arm covers with new gaskets, tighten down covers, but DO NOT OVERTIGHTEN. Replace all hoses removed. You're done! Start the engine and listen for a any loose valves. If you hear a ticking sound you'll need to pull the rocker arm covers again, and adjust the loose valves. You might also want to do a compression check to ensure none of the valves is too tight.

Lessons Learned and Good Suggestions:

Do not purchase the lever type of valve spring compressor, as it won't fit on a number of valves.
Do not overtighten the spark plug air compressor attachment in the spark plug hole, as it's difficult to remove.
Purchase a replacement EGR pipe clamp, maybe two, as the original one will probably break when removing. There is a special tool required for crimping the new clamp on the EGR pipe, but you can use a pair of dull side cut pliers and brute strength to crimp as an option.
The replacement of the EGR clamp was the most frustrating of the work done, as the seal must be good, or you'll hear an exhaust leak.
Use shop rags to cover the head openings (oil drainback holes), to protect from dropping dirt/tools/something into the engine, as this would be very bad.
Don't overtighten the rocker arm (valve) covers, as this can cause leaks.
You may need to use a socket over the valve stem when replacing the lower cap/boot seals, to tap it down to make a snug fit.
Two man job, nice to have another pair of hands around.
The o-ring valve stem seal goes on the SECOND grooved notch of the stem. Lower one if you want to look it that way. Take note as you remove the old seals. It's likely the old seals will be brittle, and will break apart when removing. Be sure to clean up the broken pieces.

Date last updated: June 16, 1995
Copyright © 1995 Eric E. Frash - FRASH_ERIC_E@Lilly.com

From James Butler, butler@ELVIS.COMM.MOT.COM

I've done this on my '79 Camaro, and while the cars aren't the same, you might appreciate some of the problems that I had. Remember that the context here is a GenII F-body, so issues related to floor shifters and such will be somewhat different for you.

Connecting an existing floor shifter: We had to fashion two brackets to connect the cable to the 700R4. The first bracket is that which fastens the cable housing to the tranmission case; we did this by getting a 700R4 bracket from a later-gen Camaro and combining it with the bracket from the original TH350 to yield one which would affix *my* GenII shift cable to a 700R4 case. The second bracket is that which connects the cable to the transmission shifter shaft; we cut up the original and rewelded it together so that the cable's throw would properly select either PRND432 but not 1 (first). If you want to select *all* of the positions and you want to keep your original shifter, you're on your own (NOTE: There is a kit to convert GenI and early GenII shifters for operation with the 700R4, but I haven't seen it personally). B&M's got some parts if you want to go with a non-original shifter, and maybe others do too.
Getting a usable dipstick: We wound up getting a dipstick tube from a Caprice, shortening it 3" or so, and then using my original dipstick. We looked for a while before coming up with a workable combination. Clearly, we had to find one which had the proper physical shape, but when we found one it was too long, hence the shortening by the proper amount to reuse the original TH350 dipstick.
Connecting the TV cable: Supposedly there exists off-the-shelf brackets that can be used to mount the TV cable to the manifold, but *I* never found one that worked correctly for *my* application. Other than some generic brackets that are on the market (B&M has one in their blower catalog and Edelbrock's got one in the carburetor section of their catalog), and a few other GM brackets which only fit some specific manifold/carburetor combinations, there's little available. We fashioned one by cutting up a GM piece that we bought and welding it to some other appropriately formed pieces which enabled it to then be bolted to a carburetor stud and maintain the proper geometry with the carburetor. Oh, and don't forget that you've got to connect it *to* the carburetor, and *that* requires that the throttle shaft *happen* to have a bellcrank on it that's got a hole the *right* distance from the shaft so that the *throw* is correct, and..., and... This isn't an impossible task, but be prepared.
Setting up the transmission's shift points: Even *after* you manage to get the transmission in and everything connected, you *then* have the fun of finding out, for the first time, where RPM-wise the transmission builder (or rebuilder) set up the transmission's upshift/ downshift/ shift firmness/ shift timing, which may or may not BTW be appropriate which your engine's power band/ torque converter / rear gear combination. I've spent and continue to spend time working this out (note that I don't like to row the shifter, so I've working to get the shift points where I feel they should be when Drive is selected).
The type of converter to use: I was inclined to use a lockup torque converter, which only seemed natural since the 700R4 is setup to accommodate one, but after trashing two of them (and finding out later from rebuilders such as Art Carr that they're rather notorious for living short lives behind stronger engines, but your mileage may vary I suppose) I quickly came to the conclusion that my life and wallet would be much better off with a non-lockup. Too, while I had the lockup, it was a constant battle to configure it so that it would lock/ unlock at the best time; I'll let you think about this one (note that the lock/ unlock issue is unrelated to the converter failures that I had, as those converters were definitely unlocked during WOT).
Connecting the linkage so that the backup lights/ keylock steering wheel work correctly: This was yet another kludge job requiring a MIG welder.
Setting up the rear mounting on the crossmember: In my car, using the stock 700R4 rear mounting position, we had to cant the crossmember so that it would clear one rear corner of the transmission. That is, one side of the crossmember is bolted to the subframe slightly forward of its other side. This wasn't really a *problem*, but it was certainly one of those unexpected issues. A different tailshaft housing is available for the 700R4 which positions the rear mounting pad at the same distance from the engine as the TH400, which presumably allows one to use the TH400 crossmember mounting position. If you need this part number, drop me a line.
Driveshaft: You'll have to shorten the driveshaft to fit the 700R4 since it's longer than a TH350. Note that the TH400 tailshaft housing mentioned above does not, though its use, eliminate this issue; it's unrelated.
Adjusting the pinion angle: The 4L60's rear mount will position it a little too high... higher than a TH350. Some rags mention that the crossmember's pad can be re-welded to position the tailshaft lower and at more correct position for retrofits, but we didn't do that and two problems occurred. First, the header's collectors were thus too close to the floorpan, and second, the driveshaft angle was about 2deg off. We wound up bending the headers down somewhat to clear the floorpan and shimming the rear axle (and consequently the pinion) to the correct angle.

I suppose there's a bunch of other issues that I've forgotten, but just like so many things, once you've surmounted the problems and have it working, it's a dream to drive and you'll quickly forget the pain. I have.

Jim

Doing CAGS the Right Way

by John Rovner JOHN_ROVNER@NOVELL.COM

All of the below was obtained from the '94 Corvette service manual BOOK 2.
Use section 8a for all of this info.
Use page 8a-20-7 for PCM.
Use page 8a-22-3 for ECM models

Terms I am using :

Vin P - Base model
Vin J - LT-5 optioned
ECM - Pre '93 Vin P or all LT-5 ZR-1's
PCM - '94 and newer Vin P

ECM/PCM connector block colors:

Connector Block	ECM connector color	PCM connector color
A	Gray	Red
B	Red	Black
C	Green	Clear
D	Brown	Blue

Most people who disable CAGS crawl under the car and pull the plug where it goes into the transmission. There is a better way that also disables the shift light. Simply disconnect two pins/wires from your ECM/PCM. You can get a pin extraction tool for a couple of bucks at any place like Radio Shack. Tape off the ends or maybe use some shrink tubing.

For all ECM users,

pull DRK BLUE [ CIRCUIT 1493 ] wire from block B, pin 19 to disable CAGS
pull WHITE [ CIR 375/776 ] wire from block D, pin 6 to disable the shift indicator

For PCM users,

pull GRAY [ CIRCUIT 324 ] wire from block B, pin 13 to disable CAGS
pull WHITE [ CIR # 375 ] wire from block D, pin 15 to disable the shift indicator

It would be quite simple to use a single throw, double pole switch, if you wanted to toggle these functions on or off.

John Rovner
Novell BIS NCS Testlab

K&N Filters

From Hib Halverson, finspeed@aol.com

Hi VetteNetters, Back in Dec. and Nov. there was quite a bit of discussion of the K&N Filter. At the center of the controversy were questions about the K&Ns filtering ability ie: though its performance enhancing features are not in doubt, people wondered how good a filter it is.

The discussion got even a bit heated with someone on the anti-K&N side coming out and saying that the K&N pretty much sucks as a filter and is not good for your engine.

The only post I saw, pro or con, that backed up statements with test data was a post that cited a 1992 British Motor Industry Research Association dust filtration efficiency test of the K&N air filter. While this test was discussed previously, there are some things in it that need review.

The test procedure was done according to ISO standard 5011, an international standard for air filters of the type used on heavy-duty and commercial vehicles.

The filter was a K&N commercial type unit using K&N's oil-impregnated, gauze media and measuring 16.14in. long and 10.43in. in diamter. Air flow was 550 cubic feet a minute. The filter test "dust" was "coarse grade" dust as specified by standards used by ACDelco in testing their filters. Coarse grade dust is made up the following percentages of varying diameters of dust particles.

0-5 microns      12%

5-10 microns     12%

10-20 microns    14%

20-40 microns    23%

40-80 microns    30%

80-200 microns    9%

The starting pressure differential across the filter was 26.45 inches of water. The test was run until the pressure differential reached 31.49 inches of water then the amount of dust trapped by the filter was determined and compared to the total amount of dust introduced to the filter. Dust introduced was 5.1680 lbs. and the dust trapped was 5.1307lbs. It took 102min. for the filter to reach the 31.49in. of water level. Filtration efficiency was 99.28%.

Now, I have to qualify this test a bit to put it in the proper relation to a street high performance engine in a Corvette. First of all K&N commmercial filters typically are four-layers and units typically sold for use in passenger cars are three-layers. K&N has told me that the efficiency of the three-layer filter is 97% and additional tests back that up.

Next, the K&N commercial filter tested, had more filter area that the typical air filter we see in a high-performance V8 application, such as a 3x14in. unit. However, the efficiency of the filter media would be about the same. Only the time to reach a specified restriction level would change. It would be less because, for a given type of dust and a given flow rate, the smaller the filter was, the faster it would plug up.

Lastly, virtually no Corvette engine, run in a street high-performance duty cycle is going to see coarse grade dust in any significant amount unless the car is used as a farm or construction impliment.

Another test that's been done with K&Ns was in 1983. Again, it was done by the British MIRA but this test was done according to the SAE J726 standard which is a bit more familiar in this country. This test was done with AC fine grade dust, the composition of which is different and perhaps more typical of "dust" a street engine would encounter.

0-5 microns     39%

5-10 microns    18%

10-20 microns   16%

20-40 microns   18%

40-80 microns    9%

The test was done with a K&N for a motorcycle application which is a three-layer filter. The initial pressure differential was .825in. of water and the ending differential was 6.85. The airflow rate was 40 cfm. The dust introduced was 15.6 grams and the dust trapped was 15.1 grams. The efficiency of the three-layer filter was 96.8, fairly close to the 97% K&N claims for its street high-performance automotive filters.

While the motorcycle filter is obviously much smaller than a V8 unit, the efficiency would be about the same. With a bigger filter, the time to reach the ending level of restriciton would be longer.

In yet a third MIRA test done with filters of a size typical of V6 engines in high-performance sports coupes, two K&N oval filters were tested. One was a 2.56x7.48x6.18in. and the other was 3.22x7.05x4.5in. The test was run to ISO 5011 and AC fine grade dust was used. The filters' efficiency levels were 97.5% and 97.6% respectively.

In my opinion these tests show convincingly that the K&N, oil-impregnated, gauze air filter is not only capible of low restricion but high filtration levels. All of the tests discussed here showed efficiency levels above that of the 95% which most OEs specifiy.

Many off-road racers must agree, because a lot use the K&N and, if the K&N works in that kind of enviornment and those off-road race engines are reliable, it must be a heck of a good filter.

In the U.S. Chrysler markets factory-approved performance kits for some of its truck engines. The kit includes a K&N filter and the kit's use is covered under the factory warranty. Chrysler would not offer a kit such as that if the K&N Filter could not meet OE filter efficiency goals.

In Japan Nissan markets similar factory-approved performance kits for a couple of models that are offered only in the Japanese domestic markets. Like the Chrysler, kits, the Nissan kits include K&N filters.

Also, the one way a K&N can fail as an air filter is if it is run, contrary to the manufacturer's instrictions, without being oiled. Another way it can fail is if it is run with the wrong kind of oil. If you use a K&N, best results comes from cleaning annually and reoiling every six months. If you operate your Corvette in a dusty environment (the coarse dust) clean and reoil more frequently. When you reoil, use only K&N's filter oil. Foam filter oil, engine oil, WD40 or ATF are not the proper products with which to reoil a K&N and will significatnly degrade the filter's efficiency.

cYa
H. Halverson

Changing plugs on an LT1

The secrets to changing spark plugs on an LT1. Not that hard, even 2 and 4. All eight can be done in under 2 hours, much less with practice.

Plugs 2,4: remove spark plug wire holder from cylinder head. Might help to remove middle inner fender panel as well and go at the plugs through the wheel well, but I can get to both from the conventional route w/o trouble.

Plug 6: not very difficult, and requires nothing be removed from car.

Plug 8: will help to remove plug wire holder from head to get this, but I have done it without removing anything from the car except the wire boot from the plug itself.

Passenger side should take 30 minutes.

Plugs 1,3: remove inner fender panel from wheel well. Go at plugs from wheel well with a 12" extension on your wrench. Should take about 40 minutes. Be careful!

Plugs 5,7: here is where the real fun is. You must partially remove the AIR system. Locate the T-fitting in the AIR system just above the exhaust manifold. Disconnect the rubber hose going forward out of this T to the metal pipe that goes into the manifold. Next, follow the hose out of the bottom of the T. Disconnect it at the fitting under the ASR box. Now, the AIR hosing will lift out of your way. Take off the wire holder from the cylinder head. You will now be able to change these two plugs. Neither needs to be accessed from below.

To change these plugs you must be patient and be able to thread plugs w/o being able to see what you are doing, just feeling what you are doing. Use anti-seize compound. I use a spark plug socket with a foam insert to protect the plug and with a 11/16" hex pattern on the outside. Then, instead of putting my breaker bar or ratchet into the plug socket, I put a 11/16" 12-point on the ratchet, and use that socket around the plug socket. This is of immense help. I hand tighten as far as I possibly can, then slowly wrench tigten.

Bill Jurasz

Displaying A/C error codes

To enter diagnostic mode (Built in Test):

Ignition Key On, engine off Push and hold the fan up arrow & fan down arrow at the same time. After about 5 seconds, the LCD where your temp/fan speed is displayed will show "-00". Push the fan "AUTO" button, and the LCD will display any fault codes stored in the programmer.

 Fault Code     Description



     00         no faults detected

     01         Temp Door Motor Circuit Failure

     02         Temp Door Motor Circuit Failure

     03         Ambient Sensor Open

     04         Ambient Sensor Short

     05         In-Car Temp Sensor Open

     06         In-Car Temp Sensor Short

     07         Solar Load Sensor Open

     08         Solar Load Sensor Short

     09         Low freon detected

     10 or ---  UART Failure

Push any lower button (ie vent, heater, AUTO, etc) to exit the diagnostic mode.

FYI, pushing the fan up arrow or down arrow while in diagnostic mode, followed by fan AUTO, allows you to check other parameters as well. However, I'd need a few more pages to explain everything.

Jim Mason
90 L98 - 6 spd - Z51

Four wheel alignment for Vettes

from Chris Teague '90 Vette (ASP) teague@us17503.mdc.com

Several people asked how I do my alignment at home, so here goes:

I use a 6' Carpenters level to find a level spot (side to side) in my garage. If you cannot find one, use masonite shims under in the low spot(s) to make one. Most garages slope out for drainage, but this will not affect the alignment as long as it is level side to side. Set all 4 tire pressures to your normal pressure (~35 psi for street tires). Make sure the inside is relatively empty of heavy items.

I have a castor/camber gauge that is just a level that fits on the wheel, and reads off in degrees. They go for about $70 at any of the racer supply stores. Or just use a regular level with blocks attached to fit on the wheels. With the regular level, you will need a scale to read off the distance from level, and convert that to degrees. (For a 17" wheel, 1/2 degree is about 0.15").

How to Measure Castor and Camber: Use the level or castor/cambor gauge to read the camber of all 4 wheels. Camber is the tilt in or out looking from the front of the car. Write these numbers down. Negative camber is the tire/wheel tilting inward at the top. For the front, we need to measure castor. To due that, turn the wheel full lock to the left, and then measure the camber on both L and R wheels. Then turn the wheel full lock right and measure the camber. Subtract the two left wheel camber numbers and that will be the left wheel castor setting, and the do the same for the right wheel Note that you really want to turn the wheel +/- 20 degrees, but full lock is real close and much easier to duplicate. Also, the actual castor setting is not critical, but any difference side to side is since it will make the car pull to the side that has more castor. Toe must be measure/adjusted AFTER castor/camber is adjusted. Recommeded Settings: The follwing Settings are only a guideline, and I offer no warranty expressed or implied:

Street:

Camber: 0.7 Degrees negative Front, 0.3 Degrees Rear
Castor: 5-6 Degrees positive castor front (But within about 0.3 to 0.4 degrees side to side.
Toe: 1/8 inch in front, 1/8 inch in (rear) Both are total numbers (Left is 1/16" and right is 1/16")

Autocross

Camber: 1.3 Degrees negative Front, 0.9 Degrees Rear
Castor: 4-5 Degress positve
Toe: 1/8 inch OUT front, 1/8 inch in (rear)

The autocross settings maximize turn in and grip of the Vette, at the expense of stability and tire wear. On the street, the car will wander from the toe-out and may seem nervous. On the track, it will have excellent turn in response.

How to Adjust: For autocross settings on the late model, just jack up the front of the car, and remove all of the shims from the upper a-arm. This will give you about 1.1-1.3 degrees camber, more if your car is lowered.

For street, most Vettes come with 0.0 to + 0.5 degrees camber, so you probably want to remove some shims. Pulling out the same number of shims from each side of the a-arms changes only camber. Pulling out only shims from the rear of the a-arm increase negative camber and increases castor. The big shims are worth about 0.25 degrees (roughly), and there are several smaller sizes. For street, I would worry more about getting each side the same than the actual number. Try to keep the camber with 0.2 degrees, and the castor within 0.3 degrees side to side to minimize pull. For autocross, I would worry more about getting the most camber, and I accept more variation side to side since I want to maximize traction, not make the car feel comfortable on the street.

There is a chart in the shop manual you can follow, but it lets you go farther apart than I have stated. (It is really to let them do fast alignments within "factory specs")

In the rear, you have to remove the wheels, then loosen the inner lower control are bolt (185-ft-lbs), and rotate the bolt to increase or decrease camber. The washer is eccentric, moving the arm to the outside of the car increases camber, moving to the center of the car decreases camber. Be sure to Torque the bolts back up to 185 ft-lbs. Otherwise, these bolts can slip, changing your alignment. My torque wrench only goes to 150, so I stop there, but I check mine every few months, and I HAVE had them slip before.

The back is tricky. Use small increments. The lines on the washer about about 1 degree each, and there are lots of them, fooling you into thinking you need to move the bolt a lot. A little will do.

After you change Castor/Camber: Once you have changed your front and rear camber and front castor, put the wheels back on and drive around the block. Then measure again. This is an iterative process. You probably won't get it perfect the first time. This is why it takes a long time. Your local $29.95 guy just makes sure you are within factory specs, which are faily wide. Get the castor camber to where you are happy before continuing on to the toe.

Toe: Toe is the easiest to adjust, but must be done after the castor/cambor is changed, and you have driven around the block.

VERY IMPORTANT: If you jack you car up at ALL, you must drive around the block to settle the suspension before measuring castor/camber or toe. Otherwise the ride height is off, throwing all you measurements off. This is the single most common mistake I see the shops doing, not settling the suspension of the car. Pushing up and down on the fender of a Vette won't cut it, it is too stiff, and the tires are too wide. Drive it around the block.

For the front toe, I just use a steel tape measure. Measure the distance between the two tires from the front and then the rear. Subtract them to find the toe. Use the exact same tread front and rear, and make sure the tape is not hitting any components under the car. This takes two people, but my wife does not mind. Make sure the wheel is straight before you decide which side to adjust. You can do the front toe from under the hood. Just loosten the jamb nut on the tie-rod end and turn the steering arm to adjust. After you adjust, drive around again before you measure.

For the rear, you can use the above method in a hurry, but that is not really accurate enough. Since the rear wheels don't turn, you really need to measure each side independently. I use 4 jackstands, two on each side of the car, with a long string tied between them parallel to each side of the car. Note to due this right, you really need to find the centerline of the car by measuring from the suspension pickup points. I cheat, and just measure to the center of each wheel. Remember, that the rear track on a late model is 0.8" wider, so leave 0.4" more distance from the front wheels than the rear. From this parallel string set at the height of the center of the wheels, you can measure the distance from the front of the wheel to the rear. The difference is the toe in/out. I use the wheels to measure, not the tires. The specs I gave are at the tires, so you might have to adjust a little depending on the height of your tires. Once you have gone to the trouble of setting up the string, you could just as well measure the front toe in also. That might be easier to get the wheel straight.

To adjust the rear to, just loosen the jamb nut on the tie rod ends. You will probably need some vice grips or plies to move the rear toe rod since it is not machined for a wrench, and it is a tight fit near the mufflers. I do it without jacking up the car, but it is tight. Once you adjust the toe, you have to drive around the block again before you can measure to check the results.

In Conclusion: This process will take at least 2-3 hours, and may seem tedious, but it will give you an accurate alignment, plus you can change your own settings. I adjust my suspension every few months. I use a tire pyrometer to check tire temperatures, and try to keep them even for autocrossing. The settings will very by tire brand. The autocross settings I gave are for BFG. Yokohamas like more camber, but it is hard to get more unless you lower the car. If you are serious about doing it, I would recommend the camber gauge. But I used a standard level for years before I bought my camber gauge. You do *NOT* need a $40,000 computer system. Patience at home will be more accurate than a fancy alignment machine run by a rushed operator whose only goal is to be within the +/- 1 degree stock specs.

The most important setting for feel/handling is toe. Next is camber, and last is castor. More castor give better high speed stability at the expense of steering response. Differences side to side in castor, and too a lesser extent, camber, is usually what makes a car pull. Toe can do this also. Rear toe out is dangerous. The stock Vette does not have enough front camber to make it understeer, so it is safer for the average driver. My specs should get a street vette closer to neutral without giving up high speed stablility and without hurting tire wear too much.

I hope this was not too long. Good luck,

Chris Teague '90 Vette (ASP) teague@us17503.mdc.com

This list of brake pads was compiled by Scott Griffith, skod@sun.com, from his publication, "Building the Perfect Pony".

For the street - try Performance Friction CM-S compund or CM90

cold hot rotor appx. grip grip noise wear price PowrPad Carbon Kevlar A A D B $150 CC Motorsport Cool Carbon A A D B $130 Stainless Steel Brakes Carbon Kevlar A A D B $150 Porterfield Carbon Kevlar A A D B $130 Performance Friction Black (CM-S) B B B A $60 Performance Friction CM90 B A B A $80 Performance Friction Red (CM80, 5180) D B C B $80 Berformance Friction Blue (CM83, 5183) D A D C $80 Braketech black 4000-1 street A B A A $60 (N/A) Braketech black 4000-3 dustless street A B A A $60 (N/A) Braketech red 2000-4 hard full race pad D B D C $100(N/A) Braketech red 2000-5 soft autox pad A C B B $60 (N/A) Onadime Carbomet Plus A B A A $30 Various semi-metallic (raybestos, wagner) A C A B $40 Hawk Brake Black Hawk Carbotic (HBC9000) A A B D- $85 Hawk Brake HPS6000 A B B B $85 Hawk Brake Blue Hawk Carbotic To be tested $? Repco Metalmaster " $? Performance Parts Inc. Kevlar " $60

Late Model Suspension Chart

Courtesy of Hib Halverson, finspeed@aol.com
Widen your browser to see the entire table.

Model year

Suspension RPO

Front Spring Rate (N/mm)

Rear Spring Rate (N/mm)

Front Wheel Rate (N/mm)

Rear Wheel Rate (N/mm)

Front Antiroll bar dia (mm)

Rear Antiroll bar dia (mm)

Wheels (in * in * mm offset) Front

Wheels (in * in * mm offset) Rear

Front Tires

Rear Tires

Shocks

Front Lower Bushings

1984

FE1

63.5

72.0

21.5

28.6

24 S

20 S

15x7x17 16x8.5x32

215/65R15 255/50VR16

Z51

102.0

87.5

28.6

37.5

25 S

23 S

16x8.5x32

16x9.5x38

255/50VR16

1/4

1985

FE1

54.0

39.9

17.5

24.1

24 S

20 S

16x8.5x32

255/50VR16

1/3

Z51

63.5

57.2

26.0

30.6

30 S

24 S

16x9.5x38

255/50VR16

1/4

1986

FE1

51.8

39.9

18.0

24.1

26 T

20 S

16x8.5x32

255/50VR16

1/3

Z51

66.5

57.2

26.0

30.6

30 S

22 S

16x9.5x38

255/50VR16

FE1*

54.4

39.9

19.0

24.1

26 T

19 S

16x8.5x32

255/50VR16

2/3

1987

FE1

51.8

39.9

18.0

24.1

26 T

20 S

16x8.5x32

255/50VR16

1/3

Z52

51.8

39.9

18.0

24.1

30 S

20 S

16x9.5x38

255/50VR16

Z51

66.5

57.2

26.0

30.6

30 S

22 S

16x9.5x38

255/50VR16

FE1*

54.4

39.9

19.0

24.1

26 T

19 S

16x8.5x32

255/50VR16

2/3

Z52*

54.4

39.9

19.0

24.1

26 T

20 S

16x9.5x38

255/50VR16

1988

FE1

93.1

39.9

26.7

25.7

26 T

22 S

16x8.5x50

255/50ZR16

1/3

Z52

93.1

39.9

26.7

25.7

26 T

22 S

17x9.5x56

275/40ZR17

Z51

115.5

57.2

30.8

33.5

30 S

24 S

17x9.5x56

275/40ZR17

FE1*

93.1

39.9

26.7

25.7

26 T

22 S

16x8.5x50

255/50ZR16

Z52*

93.1

39.9

26.7

25.7

26 T

22 S

17x9.5x56

275/40ZR17

1989

FE1

93.1

39.9

26.7

25.7

26 T

22 S

17x9.5x56

275/40ZR17

FX3

93.1

39.9

26.7

25.7

26 T

22 S

17x9.5x56

275/40ZR17

Z51

115.5

57.2

30.8

33.5

30 S

24 S

17x9.5x56

275/40ZR17

Chal.

115.5

57.2

30.8

33.5

30 S

24 S

17x9.5x56

275/40ZR17

FE1*

93.1

39.9

26.7

25.7

26 T

22 S

17x9.5x56

275/40ZR17

FX3*

93.1

39.9

26.7

25.7

26 T

22 S

17x9.5x56

275/40ZR17

1990

FE1

93.1

39.9

26.7

25.7

26 T

24 S

17x9.5x56

275/40ZR17

FX3

93.1

39.9

26.7

25.7

26 T

24 S

17x9.5x56

275/40ZR17

ZR1

96.2

39.9

27.1

25.7

26 T

26 S

17x9.5x56

17x11x36

275/40ZR17

315/35ZR17

Z51

115.5

57.2

30.8

33.5

30 S

26 S

17x9.5x56

275/40ZR17

R9G

115.5

57.2

30.8

33.5

30 S

26 S

17x9.5x56

275/40ZR17

FE1*

93.1

39.9

26.7

25.7

26 T

24 S

17x9.5x56

275/40ZR17

FX3*

93.1

39.9

26.7

25.7

26 T

24 S

17x9.5x56

275/40ZR17

1991

FE1

93.1

39.9

26.7

25.7

26 T

24 S

17x9.5x56

275/40ZR17

FX3

93.1

39.9

26.7

25.7

26 T

24 S

17x9.5x56

275/40ZR17

ZR1

96.2

39.9

27.1

25.7

26 T

26 S

17x9.5x56

17x11x36

275/40ZR17

315/35ZR17

Z07

115.5

57.2

30.8

33.5

30 S

26 S

17x9.5x56

275/40ZR17

FE1*

93.1

39.9

26.7

25.7

26 T

24 S

17x9.5x56

275/40ZR17

FX3*

93.1

39.9

26.7

25.7

26 T

24 S

17x9.5x56

275/40ZR17

1992

FE1

73.2

39.9

23.9

25.7

26 T

22 S

17x9.5x56

275/40ZR17

FX3

73.2

39.9

23.9

25.7

26 T

22 S

17x9.5x56

275/40ZR17

ZR1

75.4

33.0

25.4

22.6

26 T

26 S

17x9.5x56

17x11x36

275/40ZR17

315/35ZR17

Z07

90.1

57.2

29.4

33.5

30 S

24 S

17x9.5x56

275/40ZR17

FE1*

73.2

39.9

23.9

25.7

26 T

22 S

17x9.5x56

275/40ZR17

FX3*

73.2

39.9

23.9

25.7

26 T

22 S

17x9.5x56

275/40ZR17

1993

FE1

73.2

39.9

23.9

25.7

26 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17

285/40ZR17

FX3

73.2

39.9

23.9

25.7

26 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17

285/40ZR17

ZR1

75.4

33.0

25.4

22.6

26 T

26 S

17x9.5x56

17x11x36

275/40ZR17

315/35ZR17

Z07

90.1

57.2

29.4

33.5

30 S

24 S

17x9.5x56

275/40ZR17

FE1*

73.2

39.9

23.9

25.7

26 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17

285/40ZR17

FX3*

73.2

39.9

23.9

25.7

26 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17

285/40ZR17

1994

FE1

73.2

39.9

23.9

25.7

26 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17E

285/40ZR17E

FX3

60.0

26.0

19.0

18.0

26 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17E

285/40ZR17E

ZR1

75.4

33.0

25.4

22.6

26 T

26 S

17x9.5x56

17x11x36

275/40ZR17

315/35ZR17

Z07

90.1

57.2

29.4

33.5

30 S

24 S

17x9.5x56

275/40ZR17

FE1*

73.2

39.9

23.9

25.7

26 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17E

285/40ZR17E

FX3*

60.0

26.0

19.0

18.0

26 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17E

285/40ZR17E

1995

FE1a

73.2

39.9

23.9

25.7

26 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17E

285/40ZR17E

FE1b

60.0

26.0

19.0

18.0

26 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17E

285/40ZR17E

FX3

60.0

26.0

19.0

18.0

26 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17E

285/40ZR17E

ZR1

75.4

33.0

25.4

22.6

26 T

26 S

17x9.5x56

17x11x36

275/40ZR17

315/35ZR17

Z07

90.1

57.2

29.4

33.5

30 S

24 S

17x9.5x56

275/40ZR17

FE1a*

73.2

39.9

23.9

25.7

26 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17E

285/40ZR17E

FE1b*

60.0

26.0

19.0

18.0

26 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17E

285/40ZR17E

FX3*

60.0

26.0

19.0

18.0

26 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17E

285/40ZR17E

1996

FE1

60.0

26.0

19.0

18.0

26 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17E

285/40ZR17E

FE1GS

60.0

26.0

19.0

18.0

26 T

26 S

17x9.5x56

17x11x50

275/40ZR17

315/35ZR17

F45

60.0

26.0

19.0

18.0

26 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17E

285/40ZR17E

F45GS

60.0

26.0

19.0

18.0

26 T

26 S

17x9.5x56

17x11x50

275/40ZR17

315/35ZR17

Z51

73.2

33.0

23.9

25.7

26 T

24 S

17x9.5x56

275/40ZR17

Z51GS

73.2

33.0

23.9

25.7

26 T

26 S

17x9.5x56

17x11x50

275/40ZR17

315/35ZR17

FE1*

73.2

39.9

23.9

25.7

24 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17E

285/40ZR17E

F45*

73.2

39.9

23.9

25.7

24 T

24 S

17x8.5x56

17x9.5x56

255/45ZR17E

285/40ZR17E

* Indicates the convertible body style.

CODES

S-Solid antiroll bar 

T-Tubular antiroll bar  

1-Delco  shock 

2-Delco  shock, convertible specific 

3-Delco/Bilstein gas shock 

4-Delco/Bilstein gas shock, Z51 specfic 

5-Ride-adaptive Delco/Bilstein gas shock 

6-Delco/Bilstein gas shock, convertible specific 

7-Delphi bi-state ride adaptive gas shock 

8-Delphi bi-state ride adaptive gas shock, convertible specific 

N-Normal, front, lower control arm bushings (ft. 11k n/mm, rr 2.3k n/mm) 

HD-Heavy-duty, front, lower control arm bushings (ft 13.5k n/mm, rr 3.5k n/mm) 

E-EMT tire available, 

a-early 

b-late 

GS-Grand Sport

From Steve Ravet, sravet@bangate.compaq.com

You have to remove the lower fender, which is the part with the gills. First, remove all the Torx screws that connect this panel to the rear of the wheel well. Then loosen the bolt at the top trailing edge of the panel. You will have to pull the weatherstripping back a little. It should now rotate down enough to remove the battery, after disconnecting the leads and the battery hold-down.

Removing and Installing the body

by Ken Bond, kmb2@axe.humboldt.edu

First and foremost, proper body fitting is a relatively simple job and does NOT require knowing the sequence of the original shims to be done properly. In fact, I don't necessarily follow the factory shim pattern even when I know how the original was done. I have re-fit the body on both my '58 and '61 and have helped a couple of other people do their cars ('59 and '62). I have NOT done any cars in the '53-57 grouping, but strongly believe the process to be identical. All are C-1 frame and suspension configurations with changes in things such as sway bars and spring rates, but the core frames are identical.

First, I suggest a bit of reading and study: (NOT required, but always helpful)

There are several good NCRS articles about fitting and related topics such as body-frame removal without stress cracks. The NCRS index is a good tool for finding the individual articles.
An S.A.C.E. article on Body Fitting by Roy Bratz [this is no longer available, if you can't find it, contact me for a copy]
Factory assembly manual - MANDATORY.
BE CAREFUL of the sheet(s) that will come with your kit from the various suppliers. I have a sheet from Corvette Central that shows the shim sets in the proper sequence and I have one from ZIP that shows the shim sets in the wrong sequence.

Getting the body off:

Lots of good articles. I personally like to use nylon wedding and run the material through the rear trunk hinges and under the car at the mounting bolt line just forward of the doors. There are numerous other good locations [e.g. front female hood latches].

Body-fitting once everything is restored:

ONLY necessary assumption: the frame is straight and true.
This should be checked during restoration anyway and corrected if out of spec. Three things need to be accomplished to fit the body properly.

Secure the core body unit to the frame:

A good kit comes with seven rubber shims (#3706913) ['61 numbers] that lay on the frame. Three on each side near the rear joining of the cross rail and side frame members. One shim lays on the frame at the far rear of the car. Place these visually as per factory assembly manual or kit instructions.
Place sets of shims (#366981 and #3751562) with the rubber shim on the frame and the steel shim ON TOP OF THE RUBBER shim around the EIGHT mounting points in the cockpit area. Using masking tape, secure these eight sets of shims in place.
Set body on car, and mount these eight cockpit points with bolts. Torque to specs.

Adjust the front and bottom door seams:
With the core body secure to a trued frame, now we start working on the doors. TWO completely separate ideas are needed for the complete door adjustment process. First, the doors are moved around to adjust the front and bottom gaps and the skin match between the door and the body. After these seams (gaps) are adjusted, then either the whole front or rear of the body will be moved up and down to adjust the gap at the rear of the door (this is step #3, below). Don't worry about the rear gap at this point... just the front and bottom door seems and skin match.

Each door can be moved on three separate planes; namely, up-and-down, back-and-forward, and rotated top-and-bottom. If you release the SIX bolts inside the door (three at the top and three at the bottom), you can now move the door up- and-down, and back-and-forward. Get the seams 'about right' and temporarily secure. Shim under the three locations, forward or backward, as needed.
If you release the FOUR phillips screws (two at the top and two at the bottom) that attach the hinge at the body) you can rotate the door to match the door-skin to the body- skin. Occasionally, I also have to release the FOUR bolts (two at the top and the two at the bottom) that are inside the door hinge and mount the hinge unit to the body.
I typically have to go back-and-forth a couple of times between the six bolts in the door and the four screws and four bolts at the hinges. Judicious use of shims will get the gaps to match up effectively and the door-skin to body- skin surface to line up. This is a job for two people. One inside the car to loosen and tighten bolts and a second on the outside to make the visual adjustments.

Adjust the rear door gap (seam)
By rasing either the rear of the body or the front of the body, you adjust the seam at the rear of the door. There are two body mounting bolts required at the rear of the car and the radiator mounting system also has a set of shims in it. If you raise the entire back of the body, you close down the gap at the rear of the door my moving the rear section of the body closer to the securely mounted body center section. By adding or subtracting shims at the two rear mounting points, you can open or shut-down the gap. One can also bring about the same result by raising or lowering the front of the car [remember, where ever the front goes, the doors will follow, thus if the front moves up just a bit, the doors will move back and reduce the gap between the door and the rear of the car.] I typically do almost all of my adjustment at the rear of the car. I then shim the front mounting point at the radiator simply to secure that mounting point.

I have read about going back-and-forth, shiming just a bit at the front, then going to the back, and then back to the front, etc., etc. If you have a lot of gap to close down, this is the proper way to do it. If there is just a slight amount of gap to correct, I will drop a couple of extra shims in the back and am done with it.

Remaining panels

Finally, the trunk lid, convertible top hatch, and hood are mounted. All of these mounting points allow for effective use of shims. The early corvettes were NOT precision build units and ALL were corrected to proper fit by the use of shims under the various mounting points. Don't be afraid to use shims and have a good selection of widths available before you start on the doors, trunk, hatch, and hood.

That's it!

THE NEW WORLD ACCORDING TO MEGUIAR'S
by Thomas B. Nast
Copyright 1994 by Thomas B. Nast
[References to photos deleted]

Five years have passed since I last wrote the definitive tome on using Meguiar's products to keep your car looking, well, as nice as mine. In that half-decade, some products and techni- ques have changed. Add to that certain production problems with the last publishing on this subject, membership turnover, and the recycling of old Zundfolges as kindling and parakeet cage liners; the time for a rewrite is upon us.

Credit for this rewrite must be shared with Dennis Noland of Exeter Garage of Seattle, one of the few detail shops which follows the processes outlined below; and with Terry Richards, the area representative of Meguiar's, who was kind enough to bring me up to date on new product details. I have personally ob- served or tried every operation described in this article, and routinely use the appropriate procedures on my own rolling stock. So, departing from my usual practice, I will take the blame for any errors the editors have not installed for me.

How to keeping new paint looking new always baffled me. Wash it, and I got scratches. Wax it, I got more scratches. It seems like the cleaner I tried to keep it, the more scratched it got. I'm not talking about gouges, just light scratching. Take the car to a detail shop (at least to judge from cars I've seen), and you can add swirls to the list of horrors. And I know I have a lot of company.

One solution (to which I used to plead guilty) is only to wash and wax once a year. Assuming the car is garaged, this does minimize paint damage, at the expense of appearance and oxida- tion. It is not really a solution at all, any more than a hat is a solution to baldness. Fortunately, there is a real remedy to the dilemma, and it is Meguiar's.

There are more companies making car care products than there are rust pockets in a Karmann-bodied coupe, and I cannot say that Meguiar's is the best. I have not tried them all (I have tried dozens, however). I have found only one line that seems to consistently work, with emphasis on consistent. In addition, Meguiar's has done more to see that its products are used properly (read, "successfully"), than any other manufacturer I know of (at least through its reps -- its printed literature is a bit confusing). I am not a Meguiar's salesman, and I feel that if you already have a system which works for you, stick with it. For ex- ample, I can suggest no Meguiar's compound which will do a better job on chrome than Simichrome. But if you have had decades of frustration, as I have, with $6.00 waxes wasting $3,000.00 paint jobs, read on.

Mr. Achilles takes a stand. Meguiar's has expanded its pro- duct numbers since the original publication of this monograph, continuing its entropic tradition. Unfortunately, there remains no choice but to learn which numbered product does what. Since you are not running a detail shop and are (presumably) concerned with only one or two cars, probably an half-dozen products will do it for you. Don't let the numbers intimidate you, you only need to learn a few.

Another bit of lameness is Meguiar's' naming of products -- "Professional" this, "Hi-Tech" that. To its credit, the "No. 11 Professional Hi-Tech Finesse Quick-Step" no longer appears in the catalog, but what is the difference between "No. 00 Hi-Tech Wash" and "No. 62 Carwash Shampoo & Conditioner"? Especially if your car is not endowed with a full bonnet of hair? Such monikers will not be honored by further repetition in these pages.

Theory. The theory behind Meguiar's products is simple. A system is needed to care for the car's finish, not just one or two `universal' products. First, take out scratching and don't put any in. Second, put oils back into the paint instead of tak- ing them out. Third, avoid wax buildups or anything which will dull the natural gloss of the paint.

This theory is expressed in Meguiar's products in a number of ways. Solvents and detergents are avoided. Abrasives which will not break down are not used. Nearly every Meguiar's liquid has feeder oils, which replenish the natural oils in paint. Al- most no carnauba wax is included, as solvents are needed to make it flow and it leads to wax buildup. Silicones are avoided in nearly every material except the waxes, where they are used as carrying agents. And the foam pads for machine use are about the best product to come down the pike for polishing without inducing swirling.

Typical case. The following is a typical treatment by a BMW owner new to the Meguiar's regime. It is based on about a dozen real-world applications by the author. This will help establish a baseline of products you can expect to use. We can then consider the exceptions to the rules, and the techniques involved.

First, wash with 00 or 62. Next, remove things that can be removed (e.g. windshield wipers) and mask vents, grills, or any- thing else that will be hard to clean spatter off of. Clean with No. 2. Polish with No. 7. Wax with No. 26 (one coat) or Medallion (two or three coats).

Whew, that's a lot of work! Fortunately, if you keep up with the car you won't need to do all the steps next time. Maintenance with No. 7 or No. 9 and wax is usually sufficient; if the car is kept polished and waxed, the cleaning is an annual event at most.

Now, on to more theory, technique and special cases.

Hand vs. machine application. We have been taught that the only way to clean and wax a car is by hand. This teaching, how- ever, must be relegated to the same dustbin where the teachings of the Flat Earth Society now repose. Proper use of the right power tools and products will not only yield better results than hand application, but is less likely to damage the paint in the process. I was surprised by this too, but I cannot dispute that which I have witnessed. Unless you are preparing for a body- builders' convention, use machines. Virtually all Meguiar's pro- ducts can now be applied by hand or machine.

Hand application is necessary in certain areas that ma- chines can't (or in the exercise of prudence should not be called upon) to reach. Examples would be around wiper blades, radio aerials and sharp body contours. And some people may not want to invest in machines. So because of this (and for those who won't use machines out of penury or atavism), hand application will be discussed, though it is not generally recommended.

Buffer swirls. Buffer swirls are the result of (1) the fibers which comprise wool pads, (2) compounds which don't break down, and (3) dirt being ground into the paint. Swirls are quite common when wool pads are used (and many detail shops still use wool pads). (A few years ago I attended a Porsche club event at the dealer in Tacoma, and saw three brand-new cars have their paint systematically destroyed while being "prepped" with wool pads).

Swirls are also induced by rubbing with compounds made of silicate, sand or aluminum oxide. These materials are not used in Meguiar's products, which use materials (e.g. diatomaceous clay) which break down as they are used instead of scratching up the paint. Improper cleaning of the car before waxing, or failing to clean the dirt out of the foam pads, will also result in swirl- ing. Wax conceals buffer swirls, but does not remove them. Swirls will reappear as the wax wears or is washed off. Go to a car wash and take a look at the cars as they emerge -- otherwise im- peccable cars come out with grotesque swirling in the paint, now visible as a result of the wax being stripped off. (Not to men- tion that most car washes introduce scratching.) Swirls can be usually be removed, but it is best not to install them in the first place.

The impossible. There are two things which no car care pro- duct can do. Totally oxidized paint, checked paint (thousands of tiny cracks), and peeling or flaking paint, cannot be restored. Paint this far gone (regardless of its age) should be stripped and new paint applied. No compound or wax can save that which has been destroyed. In addition, deep scratches (i.e. near or into the primer) cannot be completely removed, as obviously all the paint will be removed with them. They can be minimized, but not eliminated. So don't expect miracles, even if you find waxing cars a religious experience.

Do not be completely discouraged, however. Partially oxidized paint can be restored, and light-to-moderate scratching can be removed. If you aren't sure whether or not you are at- tempting a miracle, give it a shot -- no harm can come from trying.

Type of paint. The products and techniques you use will vary somewhat depending on the type of paint your car has. So you must determine the type of paint you are dealing with. Meguiar's divides paints into two categories, conventional and "high tech", which I will call "plastic paints" because I can't stand the hype. Conventional paints are enamels (acrylics and otherwise) and lacquers (ditto). Plastic paints include the ever-expanding family of urethanes.

This matters because the urethanes are very hard, and when they scratch (or swirl) you have to be more aggressive to get the flaws out. Conventional paints are softer, scratching and repair- ing more easily. Conventional paints will tolerate more heat than will plastic paints, so buffers can be run at faster speeds (within reason); if plastic paints are overheated, they will cloud.

Determining which paint you are dealing with can be quite challenging. Manufacturers have been inconsistent in what type of paint they use, and aren't very good about telling you. To make matters worse, a different type of paint may have been used on a repaired area than on the rest of the car. So if in doubt, ask a reputable body shop what type of paint you have. And if your car is repaired or repainted, make a note of the type of paint used.

Generally speaking, solid-color BMW's used to come with conventional paints, but now come with a single-stage urethane. Metallic painted BMW's always have a clear coat. The clear coat was of uncertain parentage (some would say it was a son of a bachelor) until about the late seventies, when urethane clear coats appeared. As many of us know, paint failure on metallic BMW's was a certainty until this change was made. Any clear- coated BMW may be treated as having plastic paint. Solid-colored BMW's of other than recent vintage will require some detective work.

To check if you car has a conventional or plastic paint, rub a small area with a terry cloth towel and some cleaner (No. 2). If color comes off the car onto the towel, you have conven- tional paint. If no color appears, you have plastic paint (proba- bly a clear coat).

Condition of paint. The condition of the paint will determine how aggressive you need to be in restoring it. New cars should need very little work (unless butchered when being "prepped"), but a five-year-old car which has been parked outside will probably need two or three additional steps. The differences will be dealt with in the text.

Equipment. In an effort to avoid inducing sticker shock, let me warn you that a one-time investment of $300 - $400 may be required to properly care for you car's paint. This could be lowered considerably by a club group purchase, or if your club purchases a buffer and DA and rents/loans them out. What you need is:

A variable speed rotary buffer for cleaning. I am satisfied with my Makita 9207SPC, which sells for about $200 discounted. Also recommended is the Black & Decker No. 6138 (ca. $280) Whatever you use, it should work at well under 2000 rpm (like 1000-1400 rpm). Some people use a variable speed drill with a $5 adaptor, but this quick-ly gets tiring; not recommended.
A dual action (DA), orbital or "hutch" (Hutchins) buffer for polishing and waxing. Polishing and waxing can be done with the rotary buffer, but a DA is a better choice for a number of reasons. It is smaller and lighter than a buffer, thus a lot easier on your back. Because of its low speeds, it splatters less material. And the low speeds and eccentric motions make it much less capable of harming a car than a rotary buffer. However, a DA is not good for cleaning. A recommended orbital is the Porter- Cable 7335; it sells for about $125. Air-driven Hutchins sanders also work well for buffing. The theory behind DAs, orbitals and hutches is to simulate hand applica- tion, but at a higher speed and with less effort.
Meguiar's foam application pads. About $50.00. Do not use wool pads. Get two yellow polishing pads (W-1000 in 8" and W-5500 in 5-1/2") and one or two 8" finishing pads (W-9000). The finishing pad has velcro backing, so you will need a backing plate (No. W-65) if you don't have one. (A new backing plate with an alignment pin for the pads is imminent). The 5-1/2" finishing pads presently only come with a backing plate permanently affixed; 8" finishing pads come with permanent backing plate or with velcro (W-1000L). If you are using a DA, get a couple of 6" yellow polishing pads for it (W-6000); these are presently the only foam pads available for DAs. If you are attaching serious scratches, get a burgundy cutting pad (W-7000).
A supply of terry cloth towels (all cotton). Thick looped toweling is best; the theory is that dirt goes down into the loops, where it cannot damage the paint. Save your marriage, and get some nice, soft towels for your car at a department store sale.
Folded and stitched terry cloth pads, about 3" square. Not absolutely necessary, but very nice for hand work.
A small, stiff nylon brush. Like a toothbrush with a gland condition. Figure a dollar.
A small wire brush (Snap-On sells a nice one with stain- less steel bristles for under three dollars).
Some dense, closed-cell foam application pads for apply- ing polish (about 3" square). Cadge these. I use foam from the thermal barrier you put under your sleeping bag when camping.
Meguiar's materials appropriate to the job. Plan on $80.00.
Apron or coveralls, free of any scratch-inducing metal on the front. Some enterprising sort should market terry cloth aprons!

To help you accept this, consider that the total cost is less than two trips to a detail shop, and the results should be sub- stantially better in most cases. If you share, borrow or rent a buffer from your club, you're probably dollars ahead the first time around.

The yellow polishing pads for rotary buffers come in large (8") and small (5-1/2") sizes. The 8" pad covers a lot of area in less time, but the 5.5" pad is good for getting into smaller spaces. My counsel is to start with a set of the 8" pads, and pick up smaller ones when you feel the need.

As to where to get this stuff locally, I bought my Makita at Tool Town on 15th Ave. West. The Meguiar's products are carried by Exeter Garage and Autosport Seattle. Look for depart- ment store or linen store sales for the towels. The orbital can be bought at Home Depot.

Technique. Technique is, of course, more important than size (850i owners take note). The following practices should be observed, as a general rule.

First, never wash, polish or wax the car in the sun. Do it in the shade, indoors or not at all.

If you are applying materials by hand, squirt the material onto the terry cloth pad, instead of onto the car as you usually would do with machine application.

With buffing wheels, use different pads for cleaners, polishes and waxes, and frequently clean or change the pad, as any dirt trapped in it will scratch the paint. Frequently refresh the pad with material, using modest quantities. When rubbing, do not use a circular motion. Always use straight strokes. This will avoid swirls and minimize the number of angles at which light is refracted by any scratches you induce. It is recommended that your strokes be back and forth, in the direction which the car travels.

Whether by machine or by hand, use light pressure. If light pressure does not do the job, try a more aggressive product (ex- cept on urethanes) and/or a higher machine speed, depending on the experience of the operator and the type of paint. Keep rotary buffers well under 2000 rpm; if working on urethane 1200 to 1400 rpm is better). Under no circumstances should you be "grinding" on the finish.

Sometimes the rotary buffing wheel will start to oscillate, jittering like an orbital sander. This is usually the result of the pressure not being on the center of the pad (plus the pads are not the best-balanced objects to pass through my shop). The oscillating motion can do your paint no good, and may well harm it. If you feel an oscillation building, ease up the pressure and try to center the pressure on the middle of the pad. Otherwise, lift the buffer off the surface and reapply it after the oscilla- tion subsides.

With an air-driven hutch or DA, don't turn the tool on be- fore the wheel is on the car. Without contact, the wheel spins up to a very high speed, slinging material and tearing up the pad. The slight friction contact with the car provides should slow the tool down to a fairly slow speed (adjust the air pressure if it doesn't).

Resist the temptation to hold the buffer with one hand while stretching to reach those hard-to-get spots, like the cen- ter of the roof. This is an invitation to disaster.

When applying liquids with buffing wheels, a number of practices should be observed. The foam pad must be kept clear of dirt and dead foam. Before reusing the pad and periodically thereafter, scrape it (while rotating) with the plastic brush un- til stuff stops coming off. If there is any suspicion of dirt caught in the foam, you may also apply terry cloth to the rotat- ing pad to clean it. The foam wheel may be trimmed using a wire brush. The wheel should be kept in flat trim, and periodic trim- ming can greatly extend the life of this fairly expensive pro- duct. Application of liquids may be in a column on the painted area being worked on, or to the foam pad directly. Which is ap- propriate depends on which product you are using (see text below and read the labels), but generally you will be happier applying the liquid to the car, as the wheel slings off quite a bit in all directions as it spins up. If the liquid has been applied direct- ly to the car, approach the liquid with the pad at a slight angle, so the liquid is thrown back onto the pad and not onto everything else. With the Makita, which rotates clockwise (when observed from above), the edge farthest from you will be the con- tact edge if you are right-handed. Once the liquid has been dis- tributed, keep the pad flat on the panel (with the weight on the pad's center) to avoid swirl marks. Do not apply cleaner to the car and then leave it sitting.

Guide the machine in long, straight, overlapping strokes, letting the machine do the work. Every novice moves the machine in a circular pattern on the panel being worked -- don't do it. On the other hand, keep the machine moving; if you rest it in one place, the paint may overheat from friction and be damaged. I have found that the trunk and hood are more easily approached from their ends than from the sides, and that the roof is most easily buffed without the use of a ladder. Avoid using the ma- chine on high points (the body creases), because it will wear through the paint. Do these by hand. And avoid objects which may catch the pad (e.g. the air vents on the hood, antenna, etc.), because the pad is too expensive to rip up and you may have the machine power itself onto the hood (or whatever), ruining your whole day. In the same vein, some system is necessary to avoid scratching the finish with a power cord or air hose. Encasing the cord in socks is one suggestion.

Also, avoid the plastic beading set in the rubber around windshields (2002, 320i). I found that the buffer can permanently disfigure these.

All Meguiar's materials have an indefinite shelf life (if not allowed to freeze), but they should be well shaken before use to evenly distribute the solids, which may settle out.

If applying a liquid directly to the car, squirt it in a 15" - 24" long bead. After it is worked in, lay down another bead on the feather edge of the area you just worked. Columns will be about 12" apart except the wax, which works better with more but thinner columns, so expect columns 8" on center for wax. The other exception is the No. 1 cleaner, which is best applied directly to the pad. When applying materials onto the pad instead onto the car, put it on the center of the pad to minimize splat- ter.

Although you can continue buffing until the liquid is most- ly dry, this is not a good idea on dark or clear-coated finishes. In general, you should stop buffing after the material begins to break down but before it becomes dry (you can tell when it is dry because it will leave a glossy finish without further wiping); stop when a thin film of material remains. At this point you can (and should) remove the film with terry cloths, rather than with more buffing.

Discrete foam pads should be used with cleaners, polishers and waxes. This is because their chemical and abrasive composi- tions differ, and mixing them up undoes what you are trying to do. So plan on having three pads, and identify the use of each with an indelible marker. Use your best pads for polishing and waxing; when they become tatty, demote them to permanent cleaning duty.

Be somewhat stingy with liquids. Most people use way more than is necessary, at least while they are learning.

Use the softest terry cloths you can. They often get softer with repeated washings, by the way. Remember, cloth is an abrasive! Any dirt caught in the cloth will undo your work, so clean the cloth frequently with a brush or another cloth, and don't be bashful about chucking it into the laundry and grabbing another, clean cloth. When washing, do not use liquid fabric softeners. Fabric stores carry terry cloth by the yard, but it will generate lots of lint before it is washed. Also, when you cut it the unbound edges will chuck off yet more fabric. So I prefer towels to terry-by-the-yard.

Finally, it is much easier on you and the car to maintain the paint (with regular washing and waxing) than it is to restore it and wax it, say, annually. (This is true of every aspect of any mechanical object, just in case you hadn't contemplated the subj. It is also true that if it ain't broke, don't fix it. Such is the yin and yang of automobiles.) The idea of an annual wax (as with Meguiar's No. 20, a polymer) will not work out if the car is used outdoors. If you just drive it around your garage, though, it's probably ok.

Splatter. It is inevitable that, using machines, slop will get all over the car. Especially until you learn just how much liquid to use and how to apply it. The car will look like a muddy dog shook itself off nearby. For this reason, you should plan on doing each step to the entire car (or as much of it as is ap- propriate) before moving on to the next step, so you only have to wipe up once after each step. You could cover areas not being worked with soft (e.g. terry) cloths, but it's probably easier just to wipe up slung liquids with terry cloths.

Other suggestions: Wear an apron or coveralls, for some of the splatter will be tossed onto you, particularly your chest and gut. And start at the top of the car and work down, because splatter obeys the law of gravity.

Another characteristic of splatter is that it gets into cracks, such as between the hood and fenders, the door jambs, and so forth. You will find a thin line of splatter behind the edge you just worked. I suggest that after each step, you open the ap- propriate panel and remove the splatter before it dries out. Use a terry cloth. It may take a couple of wipes, as a thin residue will be left after the first pass. Dry or hard-to-remove splatter can be addressed with No. 34 spray and terry towels.

Wash the car. Never wash in direct sunlight. When washing the car, do use plenty of water and never, ever use a detergent (like dish soap). Prepare a five-gallon bucket of suds, so when you wring out your wash mitt the dirt can settle out. Wet the car thoroughly before soaping. Do one panel at a time (so the soap doesn't dry before it is rinsed), starting at the top. As I apply the soapy water to an area, I flush it with the hose at the same time.

Synthetic wash mitts work well -- this is the only place for synthetics (other than the buffing pads). Terry cloth can also be used. Frequent turning and rinsing of the mitt or terry is necessary, because dirt trapped in it will scratch the finish. Car washing is where scratching problems start; after all, that's when the most grit is present to cause scratching. Don't let it happen to you.

Meguiar's recommends its No. 00 wash, which I have used for years. A more recent product is No. 62, which is available in the large quantities No. 00 used to come in and which is a good deal less expensive (though about the same as No. 00 was before No. 62 came along). Though I am resistant to change, I can find no fault with No. 62 and for reasons of economy will adopt it. The Meguiar's products really enhance the shine of Meguiar's-finished cars, without silicones and without stripping off the waxes and oils.

However, most any quality car shampoo will do fine. A qual- ity product will have no detergents and no silicones.

Meguiar's also makes a waterless spray-on wash, No. 34, which you wipe off with a terry cloth. This product, now called "Final Inspection", replaces, is much less expensive and is entirely reformulated from, the former No. 34 "Trigger Wash." The notion of wiping off a dirty emulsion scares the hell out of me, because how can you avoid abrading the surface as you wipe? The theory is that No. 34 puts a lubricant (not silicone) between the paint and the dirt, floating the dirt off. It seems to work, but I remain uncomfortable with it in heavy grime situations.

Dry the washed car with The Absorber or clean terry cloths, again turning them frequently to avoid scoring the finish with dirt particles. Leather chamois is not recommended for drying (or anything else, for that matter, except patching elbows).

Removing scratches. The technique for removing scratches depends on the severity of the scratch.

Very light scratching and light oxidation can be addressed with No. 9 ("Swirl Remover").

Light scratching is addressed with the standard cleaning routine, using No. 2.

Moderate scratching can be more challenging, and may re- quire a few trips to the arsenal. Try less aggressive products first, then more aggressive ones if needed. This is true both for the cleaners and the pads. So depending on how bad the scratching (or oxidation) is, first try No. 2, No. 1, then No. 4 (in that order); and start with an unaggressive pad (a finishing pad), moving to a moderately aggressive pad (the yellow polishing pad, Nos. W-1000 and W-5500 depending on size), then a cutting pad if that doesn't work (W-7000). Use your judgment and experience as you acquire it, though. Paints are different, and you may find it best to go right to a polishing or cutting pad. You may want to try a more aggressive pad with a less aggressive cleaner before going to a more aggressive cleaner. Note that the aggressive cleaners and pads will induce some light scratching while reduc- ing the moderate scratch; you will need to progressively rework the area with decreasingly aggressive products to polish it mirror-smooth.

Deep scratching is handled with Unigrit sandpaper (de- scribed below); 2000 grit is a good starting point. Follow this by No. 1, No. 2 and then either No. 3 or No. 7 in that order.

Severe scratching is present if you can run your fingernail over the scratch and it gets caught. This generally cannot be sanded. Likewise, if the flaw has penetrated near or to the primer or metal, sanding is not the answer. You have no choice but to use touch-up paint, let it dry thoroughly, then block sand and polish. Scratching underneath the paint, of course, requires stripping the paint and refinishing the metal.

Sanding and blocking. Sometimes a scratch will need to be sanded out, or touch-up paint will need to be blocked down so it blends with the rest of the paint. (And sometimes whole cars need to be wet-sanded, but that is beyond the scope of this article). Sanding is done with Meguiar's Unigrit (formerly Nikken) sand- paper. This has a very even distribution of grit which is closely controlled in size. It comes in grades from 80 to 2000 grit -- you will mostly be concerned with the 2000. It should be soaked overnight before use, and used with dilute No. 00 as a lubricant. The E-7200 backing pad is an excellent backing. Two sheets of sandpaper and a new backing pad run about three dollars. In sand- ing, you will simply feather the scratch out.

Sanding blocks are used to work out defects above the paint surface. Meguiar's blocks (which are fairly small) come from 400 to 3000 grade, and last almost forever. They should also be kept soaking before use.

After any sanding, expect to clean with No. 2 or stronger, followed by polishing.

Clean the car - theory.

"Cleaning" the car is not the same as "washing" the car. A "clean" car is free of oxidized paint, road tars and salts, acids found in the rain, and so forth. The car is chemically clean, and the pores of the paint are free of contaminants. Thus, a wax- based material is not used for cleaning. Meguiar's cleaners are No. 1 (medium) and No. 2 (fine) and No. 4 (heavy).

A nearly new finish will need no cleaning at all -- the step can be skipped, and you can go straight to polishing. No. 2 has feeding oils, cleaning chemicals and a buffered earth abrasive. I have found it to be gentle and effective. No. 1 is used for finishes with moderate oxidation or swirling. If you use No. 1, plan on following up with No. 2 before moving on to polishing. No. 4 is used only to removed heavy oxidation or rela- tively deep scratching; in practice, you will rarely employ it. Experience will teach you that the proper amount of cleaner is more sparing than you think -- it does not need to be slopped all over.

The key is to start with the least aggressive treatment, and only if that proves insufficient do you move on to a more ag- gressive product. If in doubt, use the less aggressive. And re- member, it sometimes takes more than one pass to get the job done. Again, you are better off with two passes of No. 2 than one pass of No. 1, but I would draw the line there. You will quickly develop a sense of just what the two different cleaners do. If in doubt, experiment on test patches, as experimenting on whole panels is very time consuming, not to mention risky.

Clean the car - by machine.

For conventional paints, try a finishing pad first, using No. 2, especially if this is maintenance cleaning; if this doesn't get the car clean (you will know after working on one panel) move to a polishing pad. Bear in mind that not all panels are the same; frequently, the roof, hood and trunk will need more aggressive treatment than the sides, due to more exposure to the elements.

For plastic paints, follow the same procedure, bearing this in mind: plastic paints are harder than conventional paints. Much harder. That means that you treat them less aggressively. Why? The harder the paint, the milder you treat it, as harsh treatment will induce scratching you can't easily polish out (induced scratching is relatively easy to polish out of the softer conven- tional paints). Thus, you will want to avoid No. 1 (use only No. 2 cleaner or No.9 cleaner/polish) and you will run your rotary buffer at its lower speeds. Also, you will probably use a finish- ing pad instead of a cleaning pad.

Clean the car - by hand. In the Meguiar's world, use No. 2 for most cleaning by hand, applying the liquid directly to the pad. Expect a moderately needy finish to require thirty to forty strokes to be clean.

Polish the paint - theory. By polishing the paint, we mean nourishing it and hiding hairline scratches. Meguiar's polishes also restore the oils which washing, age, sun, rain and air (smog) have leached out of the paint. (This is not to be confused with the "seal jobs" done by car dealerships, which involves put- ting a polymer over the paint, rather than oils into it, together with an adjustment to the customer's bank balance.) The immediate difference this step makes, especially for dark-colored cars, is so impressive that you would use polish even if it didn't renourish the paint. Meguiar's claims the benefits of its polish accrete with each application; and indeed, if maintained, very little polish is needed to replenish the paint.

The Meguiar's family of polishes includes Nos. 3, 7, and 9 (No. 5 has been removed from the line-up since last publication). Unlike cleaners, pure polishes are not abrasive. Meguiar's No. 7 is pure polish. No. 3 is a little more aggressive; it can pull a little haze off the paint, or a very light oxidation. No. 9 is a polish with a cleaner, and thus has some light abrasives in it; it is the most aggressive of the polishes. No. 9 is good for removing light swirling, or if you really don't need a cleaning step. Use it with a rotary buffer and a finishing pad, if avail- able.

Polishing by machine - in general. Polishing is not an abrasive process (except with No. 9, see above), and in fact the polish acts as a lubricant between the pad and the paint. For ma- chine application, the polish may be squirted directly onto the panels, doing one panel at a time. The polish may be buffed until the material breaks down, stop buffing before the polish dries into a powder. If one application and buffing is insufficient, try another. Be sure to observe precautions (under "Polishing by hand", below) about not letting the polish dry. Especially with No. 7, the polish will get gummy, making it unnecessarily dif- ficult to remove the excess. By the way, I have had a problem with blockages in the dispenser nozzles of No. 3; a bent paper- clip or coat hanger clears it nicely.

Polishing with buffers. If using a buffer (a rotary ma- chine) for polishing, use a finishing pad (W-9000). For polishing conventional paints, use No. 3; No. 9 is recommended for plastic paints. In addition to including mild cleaners, No. 9 is designed for the tighter molecular structure which plastic paints present. It is also the easiest of the polishes to use, if you need fur- ther incentive.

Polishing with DA. For polishing with a DA, orbital or hutch, yellow polishing pads are all that is available (and will work fine). Whether polishing conventional or plastic paints, use No. 7. Use No. 7 sparingly, and clean the foam pad often, to pre- vent the pad from gumming up.

Polishing by hand. For hand application on conventional paint, use No. 7. This polish can be applied with a rigid foam pad, a soft sponge or a terry cloth. Apply the polish directly to the car, and spread it out evenly with the pad. The pad will literally glide over the polish. The idea is to coat the panel (start by doing one panel at a time, until you gain experience with curing times) with as thin a coat as will completely cover it. The polish can be further worked into the paint using a terry cloth. The more which is infused into the paint, the better; how- ever, it should be used sparingly to avoid gumming and excessive wiping. The paint can only absorb so much; beyond that, the polish is wasted and just creates extra work.

The polish will not fully dry (nor would you want it to); hence, it can and should be wiped off with terry toweling. This can be done one panel at a time. If the weather is not too warm, removing the excess polish can be done after the whole car has been coated; however, warm weather will cause the polish to dry, and you will regret not having wiped it off earlier, so keep an eye on it.

Using the terry cloth towel, wipe gently using straight strokes. A residue will be left, which can be wiped up with a fresh terry cloth. Continue until all the polish is removed.

For hand application on plastic paints, use No. 7 or No. 9. If No. 9 is used by hand, apply it as you would a cleaner and not as you would apply the No. 7 polish.

Wax the paint - in general. Whether by hand or by machine, and whether the paint is conventional or plastic, use either No. 26 liquid wax or Medallion. It is hard to describe the dif- ferences; the No. 26 is one of the few Meguiar's materials with silicone, and it has some (not a lot) of carnauba (you don't need or want much carnauba, by the way). Meguiar's does not disclose the contents of Medallion (it probably has some silicone in it too), but Meguiar's claims that it ionically bonds to the car's finish, resulting is freedom from dust-attracting static. This is a difficult claim to verify, but it does seem to yield superior results, last longer and be even less effort to apply than No. 26. Considering how little is needed to coat the car and its greater durability, Medallion's additional cost is more than off- set. Plus, it smells a lot better than No. 26. My unconditional endorsement goes to Medallion.

Apply the wax - by machine. I have found machine applica- tion consistently yields results superior to hand application here, especially with Medallion. Use thin coats, two if No. 26, two or three if Medallion), instead of one thick one. Both of these materials are so slippery that very little is needed.

If waxing with a rotary buffer, use a finishing pad; if waxing with a DA, you must use the yellow polishing pad (the only pad available for DAs), which will carry more of the wax in its larger cells than will a finishing pad.

For machine application, apply the wax directly to the car and buff in 8" columns. Buff using light pressure and overlapping strokes, leaving a film to dry; do not buff until the material begins to break down! Use the slowest buffer speed possible; this is the great advantage of the DA.

Apply the wax - by hand. If waxing by hand, use the same procedure as with No. 7 polish. By hand, rub the wax thoroughly into the paint so that it fully penetrates. Wipe with clean terry cloths, which will take several passes a few minutes apart.

Meguiar's does make paste waxes (No. 16 and No. 26), and someday I hope to meet the fellow who buys them (five gets you eight he owns a Porsche). Paste waxes may not be used with a

rotary buffer, but can be used with an orbital. If applied by hand, they are maybe six times more work to apply than No. 26 liquid or Medallion, with an inferior result. If you wax cars for exercise, though, hand application of paste wax might be for you.

Finishing waxing. How long you let the wax dry (cure) is critical. It should dry to a hazy white. If you drag your finger across it, it should ball up and not smear. This will take five or more minutes (remember, you are not in direct sunlight). If wiped off as a liquid it does no good, and it is difficult to remove and you risk damaging the finish if it is left to dry to a powder. Of course, the warmer the day the faster the dry time. Keep an eye on it, and experience will quickly teach the optimum.

After the excess is wiped off with terry clothes, there may be oils from the No. 7 or No. 9 left on top of the wax, which looks like streaking. This is best ignored for a day, after which the oil may have been absorbed by the paint and a quick pass with a clean terry cloth will solve the problem. Otherwise, wash the car down with No. 00 or No. 62. Many have found that after the full Meguiar's treatment, a No. 00 or No. 62 wash further im- proves the car's appearance!

Maintenance. They best way to maintain the finish on your car is to keep it garaged when not in use. It is almost im- possible to keep a car looking nice if it's parked outside, espe- cially if you have a life.

To maintain the Meguiar's finish, wash with 00 or 62, polish with No. 7 or No. 9, then wax with No. 26 or Medallion. If this is done as needed, the car will seldom need the cleaning step. Since cleaning is the most time consuming, laborious and wearing on the paint, routine maintenance is a sensible (if self- disciplined) alternative to an annual or semi-annual detailing.

Clean the glass. The glass may be cleaned, again preferably by machine, using No. 1 or No. 4 (which may also be used by hand) (and don't try to do the inside of the glass by machine). I am amazed how already-"clean" glass can be made to just sparkle with this treatment; it also removes water spots. And you should do it before polishing and waxing, as there will be cleaner splattered all over the glass from when you cleaned the paint, and cleaner will be splattered over the paint when you clean the glass.

Glass can be finished with Rain X if you wish (outside only). For those who haven't tried it (and it has been around for quite a while), Rain X seals the pores in the glass, which causes rain to bead and fly off, and also gives your windshield wipers a smoother ride. The down side is complaints about hazing, espe- cially in difficult lighting conditions (dusk and dawn). I have used the stuff intermittently for about a dozen years, and I think it's a good product if used correctly (the residue must be wiped completely off, and you can't tell if it's completely off in certain lighting conditions). Give it a try; it's around $5 per bottle, which will last years.

Clean the rubber. While the wax is curing is a good time to get started on the rubber and vinyl. Cleaning is done with No. 39 and a nylon-bristled brush. On the exterior, hose off the cleaner. For protection and appearance, No. 42 works well with rubber bumpers, tires, plastic and semi-gloss painted areas. It soaks in, and may take multiple coats. It does not leave a shiny coat like Armorall, and seems to have less of a tendency to wash off in the rain (the streaks Armorall leaves as it washes off are one of many reasons to avoid the stuff).

Clean the plastic. Interior plastic parts may be cleaned with No. 40, which can be wiped on or (if the filth requires it) brushed with a brush of stiff plastic bristles. (For real grunge, No. 39 is a more aggressive cleaner.) It is an Armorall sub- stitute, except that it leaves matte finishes matte. (I dislike Armorall's making everything shiny. I also dislike the way it evaporates and deposits itself on the windshield as a haze, some- thing No. 40 also does not seem to do.)

High-impact plastics, such as turn signal lenses, can have scratches removed by machine with No. 1 and No. 3 cleaners; No. 10 can be used for cleaning thereafter. I have restored lenses I was ready to scrap with these materials. No. 10 is the industry standard for cleaning plastic airplane windshields, by the way (they are restored with a product called Micro Mesh).

Protection/maintenance of clear high-impact plastic pieces can be accomplished with No. 18, which is a cleaner/polish. It can also be used on window tints and compact disks.

Clean the wheels. Everybody has a favorite wheel cleaner, from Mothers to Eagle One. Meguiar's sells No. 36, which is used with a household paint brush and elbow grease. The No. 36 is non- acidic and is not corrosive -- it will not damage wheels. Meguiar's makes a big deal out of No. 36 being the only cleaner blessed by BBS. But because No. 36 is not aggressive, you have to put in a lot of your own effort. So try them all, and use what you like best, but don't wait until after you have damaged your wheels with another product to try the Meguiar's.

Summary of applications. By machine: Conventional paints: Wash with 00 or No. 62. Clean with a buffer, using No. 2 unless severely oxidized or deeply scratched, in which case use No. 1. Polish with No. 3 if using a buffer, or with No. 7 if using a DA or hutch. Wax with No. 26 or Medallion, preferably using a DA or hutch. Plastic paints: same as above, only polish using a DA or hutch with No. 7 or with No. 9 with a rotary buffer and a finish- ing pad.

By hand: Conventional and plastic paints: Wash with 00 or No. 62. Clean with No. 4 or 2, polish with No. 7 wax with No. 26 paste or liquid, or Medallion.

Summary of products. A summary of relevant Meguiar's pro- ducts and their uses:

00 - wash. One capful per gallon of water.
1 - very aggressive cleaner for use by machine only. Can also be used as a glass cleaner.
2 - mild cleaner for use by hand or machine. Less ag- gressive than No. 1 or 4.
3 - machine polish, for conventional paints.
4 - most aggressive cleaner, for use by hand or ma- chine. Fairly abrasive, and without chemicals. Use only if milder cleaners don't do the job.
6 - cleaner/wax for the one-step crowd and for remov-ing road tars. Not for you.
7 - glaze. Apply by hand. Full of feeder oils and other good stuff, and hides hairline scratches.
9 - swirl remover for polishing out swirling or very light scratching by hand or machine.
10 - high-impact plastic cleaner.
16 - paste wax. Apply by hand or DA/orbital.
18 - high-impact plastic cleaner/polish for clear plastics.
20 - polymer sealant. For the annual detailer type. Not recommended for fine German cars.
26 - modern paste and liquid wax. Can be applied by hand or machine.
36 - wheel cleaner. Use with paint brush and elbow grease. BBS approved.
34 - squirt bottle wash. Good for clean-up, prepping panels about to be worked and concours. Enhances gloss.
39 - rubber and vinyl cleaner.
40 - vinyl and plastic cleaner/conditioner. Goodbye Armorall!
42 - rubber cleaner/treatment.
62 - car wash concentrate destined to replace 00.
Medallion for All Paint - the most wonderful wax.
Medallion for All Leather - Meguiar's leather treat- ment. I prefer Mercedes-Benz Lederpflegemittel (p/n 0009860571), Connolly Hide food or saddle soap.
S-2005 - Meguiar's Unigrit sandpaper (2000 grit). Most commonly used grades are 1000, 1200, 1500 and 2000.
K-2000 - Meguiar's sanding block (2000 grit). Available in grades from 400 to 3000.
W-65 - backing plate for W-9000
W-1000 - 8" yellow polishing pad.
W-5500 - 5.5" yellow polishing pad.
W-7000 - cutting pads.
W-9000 - 8" tan finishing pad.

Reinforcing the cargo area of your midyear/shark

by Mike "Doc" Cobine
70373.2450@compuserve.com
corvettedoc@geocities.com

With the huge area in the back of a '63-'67 coupe, it is very tempting to let the kids sit back there or even squeeze a "so-called" adult in there when going somewhere short. However, this area has little support and was only designed with an idea of a minor amount of luggage. Putting a human body in there can easily weigh more than the floor can support and thus the floor can contact the frame crossmember and vibrate incredibly, setting up a terrible racket inside.

To prevent that, I came up with two large rubber stoppers about 2" diameter and about an inch high. I then pryed up the floor a bit from underneath to slide the stopper between the floor and the crossmember. I spaced them equally across the gap between the two side frame rails. They held in by contact pressure and were there when I sold it about a year later, after driving it daily on typical city streets and roads.

The rubber prevents any vibration from being transmitted like there would be if you used something solid like wood or metal. The dip at the front of the floor to the storage areas provide support, as does the rear bulkhead wall. So only the center section needs the stoppers.

This can also be used in the convertibles and all '68-82 cars if you haul heavy items like tool boxes in the back.

Paint touch-ups

by Doug J., djohn01@msn.com

Buy your touchup paint from GM.

Here's what I do to touch up scratches (even deep ones down to the glass), if you're patient you'll find that on a scale of 1-100 (100 being the best) you'll get a 90-95 quality touchup.

Standard colors (red, black, white, etc.) are the easiest to do. Keep in mind though that metallics are challenging to even the pros, so don't be too much of a perfectionist on your results. Take pictures of the scratches or stone chips before you start. As you're polishing and start to feel you could've done better, refer to the original photos, you'll find you probably did okay.

I use the 5-foot rule on metallics. If I can't see the touchup from 5-foot, then the job is acceptable. You'll find that basically you have three choices;

touchup with a brush and try to conceal the spot
area-spray and try to feather (a good job is marginal at best)
Spray the entire panel (sometimes this IS easier)

You can do options 1 & 2 yourself. Option 3 requires someone competent in mixing paint and operating the sprayer.

For stone chips and deep scratches, I recommend option 1. I follow these steps when I do them:

Clean area of all dirt, wax, etc.
Wet sand with 1500 paper.
Using GM Touchup paint (color code matched) and an artists paint brush, paint a minimum of 12 coats of paint into the scratch (the number of coats is relative to the depth of the scratch), letting the paint dry at least 30 minutes between each coat (you're using the paint as filler, don't worry if the paint in the scratch seem higher than the paint on the body).
After you have enough paint in the scratch, wet sand first with 600 grit, then 1000 grit, and finally with 1500 grit. Sand until you cannot feel any surface deviations where the scratch is (don't panic, you will still be able to see where the scratch was, we're not done.)
Wait 2 hours and then paint 3 coats of touchup clear coat (again using the artist's brush). After dry, wet sand with 1000 and 1500. Sand until you cannot feel any surface deviations where the scratch is (don't panic, you can still see it, we're still not done.) When finished, there should be just the slightest hint of a `mound' over the length of the scratch.
Leave it alone for 48 hours.
Now, wet sand with 1500 until you can no longer see any hint of the scratch. Then finish with a 2000 grit wet sand. Wash well...
Compound with Meguiar's #2, using a clean buffer wheel. Do this twice, then use Meguiar's #9 (swirl remover). Be sure to wash the area with soapy water and rinse it between each change of buffing. Change to a clean buffer wheel and use a good Foam Cut. Then glaze by hand with Meguiar's #3.

Practice on an out-of-the-way area before you do this project in earnest. With a little bit of patience and some practice you'll find you can get pretty good with this.

Repairing those digital dash clusters

Here is a list of places that will repair or replace the digital dash clusters found from '84-'89. Comments have been included where available.

United Radio

Automotive Division

5705 Enterprise Road

East Syracuse, New York 13057

800 448-0944

They are cheap, and seem to do great work. They will ship you a rebuilt one, and take your old one as a core, or just rebuild yours. It takes a little longer, but I had them redo the original one for my car. I live in Indiana, and it took 3 days. Shouldn't take longer than a week even if they rebuild the one you ship them. Again, sorry this is so late. I just happen to run across the address while looking through some old papers and stuff. Hope this helps you. [Brian Alspaugh]

Auto Electric Radio

Carl S. Breci, Supervisor

1841 W. Commonwealth Ave

Fullerton, CA  92633

800-321-6970

Tuning increments for Delco Radios

From Lotty (merl@LION.DE)

Here is the description how to modify the Delco-Bose radio model 16041551 to 0.05 MHz steps on the FM band. This is useful in countries other than the USA, where radio stations aren't on odd-tenth megahertz intervals.

remove the upper cover (3 screws)
remove the 5 screws holding the first PC board.
gently lift the PC board.
locate two diodes (1N4148) between display and IC labeled "DM 246 DQ 7815D" (28 pin) on the second PC board, now visible.
there is spare place for another two diodes. Add a diode to the location closest to the above IC. This can be done in two ways:
- Remove the bottom cover and the cassete drive, clean the soldering pads from solder. Solder in the diode and reinstall all removed parts.
- Do nothing of point 1), but solder the diode across the IC mentioned above. Anode to pin 10 and cathode to pin 26. (This is much easier)
reinstall PCB and cover.

If you are not familiar with radio electronics and soldering, ask a friend to do the modification, who is.

Here are the functions the other diodes control:

Diode 4 installed:
Frequency range on FM is 87.5 - 104.0 Mhz, step 0.05 Mhz, frequency range on AM is 531 - 1602 Khz, step 9 Khz.
Diode 3 installed:
Frequency range on FM is 76.0 - 90.0 Mhz, step 0.1 Mhz, frequency range on AM is 531 - 1602 Khz, step 9 Khz.
Note: D3 and D4 installed does not do anything i.e: radio act as no diode is installed in D3 and D4
Diode 2 NOT installed:
No Seek and Scan function on the radio, setting clock is as usual.
Diode 1 NOT installed:
No clock on display when radio is switched off.

Information about the casette deck:
It is a Blaupunkt Toronto SQR 46.

Midyear Clock Repair

From Mike Cobine, corvettedoc@geocities.com

Clock repair in Midyears is really simple. If you just want it to run and not want a face restoration, then pull the clock out and do it yourself. You will save more than enough for gas money.

Pull the clock out of the dash. You should be able to reach the clips holding it by removing the side panels by the radio.
Remove the back cover. Some twist tabs, I think.
Take a points file (ancient technology) and file the contact points smooth. Usually they are pitted badly and sometimes stuck.
Go to your friendly electronics supply store and get a can of TV tuner cleaner. Spray the shafts that pass through brackets, gears, etc. The idea is to clean, not drown. This will also lubricate it some. Take care NOT to get it on the face of the clock.
Test it before buttoning it back up. You need a ground wire and 12 volts. It should take off on its own, but if not, pull the points up slightly (wind it) so they will wind down to jump open again. If you have to move the flywheel, you may need to respray it.
After you comfirmed it will run on its own for 15 minutes or so, put the rear cover back on and stick it in the dash.

Fixing inflatable seats in Corvettes

Hi all. I've returned from Chicago where the wife & I spent Thanksgiving with the in-laws. I'm a little shaken, but I will attempt to explain how to cheaply repair your currently uninflatable sport seats.

First, a few mandatory disclaimers:

This fix applies only to those lumbar adjusting pumps that function electrically. If your pump motor has burned up, or you have other electrical problems, this fix will not help. This fix also assumes that the lumbar support bladder and its associated air lines are leak free (I believe the lumbar bladder and air lines are available from GM. If not, Bowling Green tends to leave the OEM labels on subcontracted parts. You may be able to contact the manufacturer direct).

O.K.. That said, here's the long-winded fix:

Buy a pair of latex rubber gloves (I'm not kidding) ($3.00 at K-Mart) & set aside.
Remove the lower seat cushion. Typically, the wires are long enough that you can simply move the cushion out of the way.
Mark the air lines which connect to the side of the lumbar adjusting pump (for correct placement during reassembly) and remove the lines. Also, disconnect the pump electrical connector.
The pump is held to the seat frame by 3 nuts & bolts. Remove the nuts and bolts, and remove the pump from the seat frame. Note: I was able to remove the pump with the seat in the car. A friend of mine needed to take the seat out first.
On one end of the pump, you'll notice 2 small Phillips head screws which secure a plastic retaining plate over the end of the pump. Remove the screws and the retaining plate.
With the retaining plate off, you'll see a small plunger inside the pump. It may or may not be connected to the motor shaft (small end of plunger) and the diaphragm assembly (large end of the plunger). Remove the plunger and set aside (Don't worry if you tear it loose from the old diaphragm).
Remove the diaphragm/frame assembly (square thing on the side of the pump body with 4 nuts and bolts). It will slide off the pump body.
Remove any debris you find in the pump body, and set the pump aside.
The diaphragm/frame assembly consists of 2 plastic frames which sandwich the diaphragm in the middle. Remove the 4 nuts and bolts which hold the frames together, split the frames apart, and discard what remains of the old diaphragm.
From the cuff of one of the "expensive" latex gloves you bought, cut out a piece the size of the diaphragm frame (make sure the piece is smooth, and not textured or it won't seal!). Trim the new diaphragm until the frame fits together. Once you have a good fit, remove the new diaphragm.
You may have noticed that the plunger is also two pieces. The diaphragm is sandwiched between the plunger and a retainer which is attached to the plunger end with a small screw. Remove the retainer and discard any old diaphragm remnants. Center the plunger on the new diaphragm, place a SMALL dab of silicone rubber sealer where the screw will penetrate the diaphragm, and install the retainer. Place the plunger/diaphragm assembly into the frame and reassemble with the 4 nuts and bolts (bolt heads installed so they will be inside the pump body).
Slide the plunger/diaphragm assembly onto the pump body, making sure the plunger end slides onto the motor shaft.
Replace the plastic retainer and screws to secure the plunger/diaphragm assembly in place.
Reassemble the pump to the seat frame, and reconnect the various air and electrical connections, replace the lower seat cushion.
You're done!

My car is a 1990. The '90 sport seat design originated with the '89 MY and continued through the 93 MY. I would expect '84 through '88 lumbar adjusting pumps to be very similar, if not identical.

It took me about 40 minutes/seat to perform this repair. I repaired my seats nearly a year ago, and they have been trouble free. Most latex rubber gloves are slightly thicker that the factory rubber, so I expect this repair to hold up well.

Jim Mason

90 L98 - 6 spd - Z51

e-mail: JMason@gwsmtp01.mdc.com

Late model window regulators

The mechanism that raises and lowers the window is not called a mechanism, it's called a regulator. If your windows don't move, or move slowly, replace the regulator with a genuine Delco unit from the dealership. The early late models use a nylon gear strip which runs in an L-shaped channel. You really wouldn't want to replace it even if you could. It'll just break again. Really dumb design. Built by the Ferro company, I think, so it is referred to as the Ferro strip regulator. By the way, you can grab the window and pull it up to the top by hand until you get it fixed. It'll even stay shut a while driving until it vibrates down again.

GM will sell you the Delco regulator for a replacement which GM started using sometime after 1986. It is 100% better. You will love it. You should put it in yourself IMHO. It is a metal gear design, real smooth, quiet, and fast. The window will go up and down in 3 seconds instead of the five seconds you're used to. The instructions that come with it are pretty good. While you're in there, if you tape down all the wiring harnesses and tape shut all the slits in the vapor barrier, you can kill all the rattles and drafts. If you've had any leaks it's also pretty easy to adjust the up position of the window to make it seat a little tighter.

The part number is #22063225 for both the left and right sides, although the part number could always change in the future.

Old Corvette radios

Call Orwin Middleton 805-482-7826. He is a retired Delco radio man in California. I sent him the original radio from my 1967 Corvette and he made it new again for a very reasonable price. His deal is the radio has to be "old" and it has to be from a Corvette. I highly recommend him and his work.

Finding a Good Dial Indiactor

From: belle65@webtv.net (Gerald Elson)
Subject: Dial Indicator-measuring devices

Hi, I'am a journeyman machinist with 30 years experience,employee by Goss Graphic Systems the last 17 years. I currently specialize in building power transmission gear trains for newspaper and commercial printing presses. This can be close tolerance workand as a general rule most of our product runs in the +.0005-.0000 range.

A dial indicator is a device used to measure runout or hop in round workpieces mounted between centers (lathe work) also used to line up a work piece perpendicular to a cutting or boring tool (grinding, boring, milling, drilling operations). In some isituations a dial indicator is used to measure things like end play on a C2,C3 axle shaft.

My advice to you would be to chek around at Pawn Shops stay away from the Chinese stuff. For the majority of the work you would use it for a 1" travel Indicator will do. Now look for a brand such as STARRETT, MITUTOYO, BROWN and SHARPE. Also SEARS stuff is good.

If you are looking at an indicator make sure the stem (rod that moves in and out) moves freely thruout it's full length of travel.001 Graduations will do but .0005 (1/2 thousandth) would be nice. Also look for an indicator that has a magnetic base with it preferably one made by the same company as the indicator.

Remember don't buy any thing that sticks, besure that the tips that screw on to the stem are there. Make sure you know it works when you leave or that you can bring it back. AND FINALLY DON"T DROP IT EVER.

P.S.Watch the needle as it moves when you test it with your finger-it should always return to the same place it started and always stop at the same place at the end of its travel (not the same place it started from).

ALSO-if you hold your finger against the end of the stem and depress it you should not be able to stop the needle from twitching around slightly when you attempt to hold one position this is a sign that you have a quality jeweled piece of equipment without a bend or binding stem.