RESTORATION PART 2
Let's go into a restoration with a little more detail.
By Skip Cain
This series will deal with mechanical restoration and restification. Restification is a recent term that means combining the "muscle" of the sixties with the technology of the nineties.Who wants to have to deal with replacing and setting points in your ignition system
Also replacing front drum brakes with disc brakes will be addressed.This will all all be about Chevelles, but will pertain to most 1964-72 GM A body cars.
As I mentioned in part one, a mechanical restoration will include a rebuild of the drivetrain.This is a good time to include some modern improvements to your engine. The valve seats need to be changed to hardened stellite, and you'll need to install bronze valve guides or inserts. The older engines were designed to operate on leaded gasoline, which shielded the valve seats, and lubricated the valve guides. Bottom line is unleaded gasoline will slowly destroy these older engines and heads.Also, I would recommend(if you have to replace the pistons)lowering the compression ratio, if your stock compression ratio is more than 10.5:1. Higher compression engines will ping and detonate on today's low octane unleaded gas. Unless you are prepared to run racing or aviation fuel, you will have to retard the timing and deal with the pinging and detonation. The difference in being able to fully advance the timing will make up for any loss of power by lowering the compression.
Another fact to consider relates to 1965 and 1966 big blocks. These engines oiled the lifters by way of a grooved rear camshaft journal and bearing. If you install a later or aftermarket cam with no groove in the rear journal, there will be no oiling of the lifters. Be sure to make your engine builder aware of this if you are having your 65 or 66 big block rebuilt. Very Important.
While I am mentioning camshafts, another important factor is properly breaking in the camshaft and lifters when you first fire up your rebuilt engine. Since you should have all new camshaft, lifters and valve springs, it is very important and critical to cam and lifter life.Most cam failures occur in the first few minutes of running. The camshaft manufacturers warn you to run the engine at 1500-2000 RPMs for the first 20-30 minutes. This may seem rude, but it insures a good oil supply, whereas idle speed will not and may cause excessive wear on the cam lobes and lifters. And always "prelube" the engine before starting and running. Make sure the oil pressure is up before firing to avoid dry parts and excessive wear.After breaking in the camshaft, change the oil and filter. Rebuilt engines are full of microscopic metal particles, lint and other debris.
I mentioned ignition points earlier. A neat "restification" trick for those of you who wish to keep your stock distributor, is to replace the points with a electronic unit. Mallory offers a Unilite conversion kit that replaces the points, and I believe there are a couple of other kits as well.These units bolt right in to your stock distributor. You'll have a couple of extra wires, but other than that it will appear stock and original. I also use a Accel Super Stock coil, which I paint black.( for originality look) They are stock sized and will fit your stock coil bracket. This setup should give you up to a 30% increase in spark over a points type ignition. With this hotter spark, you'll be ready for a better spark plug. I have tried them all, but I have to recommend the new AC Delco Rapidfires. They are gapped at .045 and really do help prevent fouling. For performance purposes you can also change the advance springs and weights to tailor the advance curve you want.
DISC BRAKE CONVERSION
This is the most frequently asked question on ACES tech. I strongly recommend changing to disc brakes if you are driving on the street. If you have a "Concours" show car trailer queen, leave your drums on. Drum brakes are old technology, and will stop your car eventually. If they get wet or hot, they will fade, and a quick stop is out of the question. I've had this happen to me, and believe me when I say it's no fun.
Disc brakes were available as an option on Chevelles for the 1967 model year. They used a 4 piston dual caliper design similiar to the Corvette. They also had to use different rims, due to caliper clearance, hence Rally wheels first appeared.These 4 piston, dual caliper design disc brakes proved troublesome, and tended to leak. For 1969, a single caliper 2 piston design was incorporated.It was standard on the SS package for that year.This is the design that you want to use. The spindels will interchange from 1964-1972. 1973 and later spindels will not interchange.Camaro and Impala spindels will not interchange.I am talking about a bolt on, no modification needed conversion.If you're lucky, you can still find some pre 73 disc brake A body cars in the junkyard. Be sure to get the master cylinder, proportioning valve, distribution block and power booster, as well as the spindels, rotors,backing plates and calipers. You will need to rebuild and recondition these components, so just don't bolt them on. The rotors will have to be turned, calipers and master cylinder rebuilt, new lines and fittings are recommended also.
There are companies that will gladly sell you a total reconditioned and new kit, but they cost some major bucks. I have an individual who reconditions the calipers, rotors, backing plate and spindels. For about $350, he'll send you a set, ready to bolt on. You will have to provide the proportioning valve, booster, lines and master cylinder. If you are doing a upgrade or a correct restoration, I recommend the use of stainless steel brake lines. They won't rust and really set off a detailed engine compartment and undercarriage.Myself, and most auto restorers, hate rust, and I for one, will use all the stainless I can(except for grade 8 applications)I would much rather pay as little more, than have to derust hardware and lines on a show car every few weeks. Hell, I even found an outfit that provides stainless steel parking brake cables and hardware. I had been waiting for that a long, long time. Most show judges will accept stainless steel lines and hardware. As a judge for NCOA's "Chevelle Showdown", I would rather see stainless than rusty steel lines and hardware.Unless you are showing Concours, you can use stainless.There is a company called Totally Stainless that manufactures complete stainless steel hardware kits, including black oxided stainless steel fender bolts.Just remember to use anti-seize, as stainless tends to gall.
Another Restification involves replacing the rubber bushings on your car. During a brake conversion is a good opportunity to rebuild the front end of the car. Replacing the ball joints,coil springs and shocks is recommended as well as the bushings on the control arms and sway bar. PST offers a graphite impregnated polyurethane bushing kit that I recommend. They won't distort and deflect like rubber, and really improve the handling. These won't squeak like the old polyurethane bushings did, and are black, not red or yellow. I replaced every bushing on my car with Polygraphite bushings by PST, and was amazed at the difference. No more wheel hop, no leaning during hard conering, and a firm high performance ride.
One last thing on brake conversions. If you are doing a complete restoration of your brakes and installing new lines, wheel cylinders, master cylinder,etc. switch to Dot 5 silicone brake fluid. It is not water soluble and won't ruin paint.Make sure it doesn't mix with the dot 3 type, as it is not compatible. It is harder to bleed, as the air bubbles like to stay suspended in the stuff, but in my opinion is worth the extra bleeding. I've had it in my car for two years now with no problems.
Stay tuned for the next part of this series. I'll go into body and paint restoration, and how to deal with that dreaded four letter word, RUST.