It is probably a safe guess that many Corvair owners do all their own work including complete engine rebuilds. If this is your first rebuild, we have some helpful suggestions that may help you avoid future disappointment!
REMEMBER the newest of the Corvairs is now 30+ years old - the oldest, 40+ years old! 200,000 and 300,000 miles is not uncommon and some Corvairs are still running on their original engines! Many of the restorations done in the 1970's, 80's and even the early 90's may now need some major rebuilding. Whether you're like those of us that still drive our Corvairs every day or only a hobbyist it's important to stay on top of problems and potential problems.
The components in a engine that are the most important to consider replacement are the piston and cylinder units. Even if you have replaced the pistons in the past you should look very carefully at their condition - aluminum air cooled engines are hard on aluminum pistons. Also, cylinder barrels can wear to the point where honing and re-ringing will not do the job because of excessive clearance. If you do opt to re-use loose fitting pistons and barrels you can expect lower compression, higher oil consumption and premature failure.
One predicament that many of our customers have confronted is that they have an engine with one bad piston, and the temptation is to only replace the bad one. That is not advised because if one piston has disintegrated the others next to it are probably not far behind. To make matters worse, after you've gone to all the expense and trouble of replacing that one piston you will probably find yourself doing the whole job over again in a few thousand miles.
The only solution to these problems is to install an overbore kit. The new pistons and precision barrels will guarantee many miles of trouble-free operation.
Any engine that has over 100,000 miles on it should also have a reground crankshaft kit and camshaft kit. In the earlier years we could get by on reusing the old camshafts and lifters or just putting new bearings with the old crankshaft but this is much more of a gamble these days. Loose clearances at the main and rod bearings will drop oil pressure throughout the entire engine and also cause premature wear and failure. Worn camshafts have the bad habit of going flat on the lobes and because the camshaft is the hardest component to get to you end up having to tear down the entire engine. Remember that when you replace the camshaft you also must replace the aluminum timing gear and the lifters. Old lifters should never be used with a new cam!
A lot of smaller parts that we didn't use to replace are getting worn out - rods, rocker arm units, pushrods etc. all seem to last forever - but time is running out if they're the originals! The cost to replace these items is fairly small when compared with the future savings in problems. I have always been amazed at how long high wear items like these sometimes last.
Most people don't do their own headwork - still you want to make sure that the shop installs 100% Teflon stem seals and replaces any worn-out or defective parts with the best modern technology has to offer. ALL exhaust guides should be our bronze type and if valves need replacing remember that we now offer the superior stainless steel type for less money than the old replacement type.
While we try to avoid having gasket surfaces machined on the heads, if it becomes necessary you will probably want to compensate for what is removed by installing extra-thick copper head gaskets.
Back in 1989 we started offering SUPERKITS - one of the first was the Engine Rebuild Superkit, If you're going to rebuild your engine then give these a look over. An engine Superkit can be tailored to your needs, but saves you money over buying the parts individually, In addition don't forget that you can get extra Volume dollar discounts when you have an initial order over $1000.00 and on. See page B-31 for more information.
Give us a call anytime if you have any questions regarding engine rebuilding or anything else, for that matter.