engine cooling

Thanks, Greg for your kind offer. I was fortunate in meeting Shawn McGarvy [a local Corvair guru] and have had tons of good advise from him. Mine is a 140 PG and the outside pipes work their way through the engine compartment on their way out the side. I'm sure the AC cars had some issues as the condenser got the outside air before the cooling fan.
If ambient air is 100 F , that should still cool the engine [with adequate air flow] but I suspect the under hood temp. was creeping up to 150-200 F when this detonating happened. Shawn kept saying "get rid of the pipes", and keep the revs up.
The original Cords had cooling problems, but for different reasons. I have read somewhere, the factory moved the numbers up on the temp guage to stop customer complaints.
Hal

Hal,
I've owned over 100 Corvairs and written The Ultimate Guide to 'Vairs with Air. I also live in balmy Houston. I have lots of experience with Corvair engines and overheating and detonation.

If your Car a Turbo or 140? Both engines had borderline cooling systems in the Corvair but for different reasons. The Turbo cars have the problem of introducing the turbine in the engine compartment with the attendant extra heat. On the 140's the larger valves necessitation making the cooling "pocket" in the head much smaller.

As you may have heard from other Corvair owners 140's are known to regularly drop valve seats. This is not as big a problem on the Turbo's, but still fairly frequent.

You are absolutely correct in that one of the major problems is recirculation of already heated air. On the A/C cars a missing or torn rear engine seal can result in the total meltdown of an engine. I don't know enough of how the engine is placed into the chassis to make specific recommendations on how to seperate the air intake from the air exhaust.

There are several things you can do to help mitigate your problem. Do you own the CORSA Tech Guide published by the Corvair Society of America? There is a section on engine cooling systems. According to GM's own data removing the bottom engine shrouds will reduce the head temperature by up to 50 degrees. Clark's Corvair Parts sells an oil pan of their own design that will also substantially reduce the oil temperature. The also sell replacement rocker covers that I DO NOT recommend. They simply will not seal to the head resulting in horrific oil leaks.

If your factory oil cooler does not have "side shields" the Tech Guide will show you how to make them out of thin sheet metal. This forces all of the air through the cooler. Another common mistake is using spark plug wire with Volkswagen style boots. It is imperative that you use plug wire designed for the Corvair. They have a lip that snaps into the top shroud. The Corvair cooling fan moves much higher CFM than a Volks which can result in the Volks style boots being forced out at even moderate speeds.

I have also seen supplemental oil coolers added to the stock ones. You should have a 12 plate cooler. Either that one or the folded fin design is okay, the eight plate isn't quite as good, and the three plate should be avoided at all costs.

The engine in your 8/10's should have a magnesium fan. Their are two earlier fan designed of steel. Both of these move more CFM than the magnesium fan, but are much harder on fan belts. If you rev your engine hard you probably can't use the steel fans as belt problems are sure to follow.

I recommend a Clark's wrapped fan belt tensioned lightly. One of the most common mistakes is overtensioning the belt.

If you have other questions I'll be glad to try and help. BTW I bought another Corvair today...a 1963 Coupe with 75K original miles and factory A/C. The car was sold new in Houston.
Good Luck!
Greg

Ken, the corvair engine has an oil cooler and the turbos and 140 HPs have a much bigger one. There is not much of a problem getting air at highway speeds, but at idle or bumper to bumper, stop and go [which we have a lot of here], the temp just climbs. I have fitted an electric fan at the front louvers and I think it helps, but I wrapped the exhaust pipes with the header wrap and that made a huge difference. {plus I don't burn myself anymore} Hal

Wondering if an oil cooler would help? I put one in a VW I drove all over West Africa and I am sure it saved me several times. As to sealing the lower half of the engine bay; would be interested to hear if anyone with an 8/10 has tried that. And how about a "parade fan" for additional ambient air circulation?

Ken Baldwin

I think one of the major omissions on the 8/10s was a proper seperation of the top and bottom of the engine. In a Corvair, great pains were taken to seal the engine bay so the cooling fan and engine air intake could only get air from the louvers on the engine cover. This worked so well, that they had to introduce hot air to the carbs for winter use [to stop icing] A properly maintained Corvair seldom if ever overheated. Our cars, on the other hand, get air at 50-100 F over ambiant [that's a guess, it could be more] I've had my car detonating so badly [with 94 octane gas] that I had to back off before a melt down.
Any thoughts on this?
Hal Klassen