bkk911

I own a 1990 C2, I understand that it does not have head gaskets. I am thinking a little modification so that I can insert head gasket to cure oil leak.

Can anyone pls advise what need to be modified and what gaskets do I need. Thanks

crg53

How many miles on the engine.?? If you go through all the trouble of taking the heads off, you may as well have them rebuild,i.e. valve guides etc..., at the same time. My advice would be to send them to Steve Weiner @ http://rennsportsystems.com, he will look after you.

Steve Weiner-Rennsport Systems

You have to machine the heads to accept a gasket. Further, we also machine the tops of the cylinders a little to aid sealing when this modification is done.

Henrik964

Is the modification of the cylinders really ncessary? Do the cylinder tops differ early to late 964? Are the PET nr on the different for the years?

prschmn

You may not even need to cut for gaskets-All the heads I see are to some degree
warped and a good surfacing cure many ills. But as another has already said if
youve got them off you probably should go ahead and do guides at the same time.

Steve Weiner-Rennsport Systems

No, but that modification helps assure a good seal and no more leaks. Its been quite successful for over 15 years so thats why I recommend doing this job properly.

prschmn

Back in the "old" days 3.3 turbos and 3.2s didn't have gaskets---but that was before your time?
Couldn't resist!

Henrik964

Interesting, have not heard of this, please post pics before and after if You have. Is this an improvement that more companies do or are You alone as You know?

Turbohead

Many of these cars were repaired by Porsche under warranty you should check if yours was done
Elliot

kwikit356

My opinion, FWIW, is that because of the larger diameter of the 3.6L cylinders they are significantly more likely to leak than the earlier 3.2L and 3.3L cylinders. The fundamental problem is that new alloy cylinder heads will all distort to some extent as they are put through the heat cycles of use. This includes the above-referenced 3.2L and 3.3L heads, as well as the larger 3.6L heads. As there was somewhat more metal surrounding the smaller heads, the gradual build-up of carbon deposits served to seal the heads before any leakage occurred. With the larger 3.6L heads first used in the 964 3.6L motor, a certain percentage of the heads leaked oil, due to normal virgin metal distortion, before there was sufficient carbon build-up to make a tight seal.

So, what is the most effective solution to the issue of having a 964 motor that leaks? I think that since we now have well-seasoned cylinder heads, they are no longer continuing to distort much at all. Given this fact, the simplest really effective solution is to carefully machine a perfectly flat surface on these heads, which will ensure a tight seal. Then, through additional heat cycles of use the carbon build-up will completely seal the head against any oil seepage.

For reference, I looked at this link: exotechpower.com, which shows the cylinder head work, but this looks like it has copper beryllium seats, so it may very well be a race motor.

prschmn

You know-Did we determine if the leak is from the lack of head gasket or is it the base O-ring
problem-that was as has been mentioned sometimes repaired under warranty?

Henrik964

Did my car and we made some changes, 20 years to late for warranty

RallyeChris

The heads and cylinders in my car were sent to Ollie's for machining and o-ring grooves. She's got maybe 5,000 miles on the rebuild done a few years ago. Not a drop of oil, even after track days.

Steve Weiner-Rennsport Systems

Touche'!!!

(I'm so old, I had a pet stegosaurus when I was a kid)

Steve Weiner-Rennsport Systems

I'm unaware of anyone else doing this, but there sure could be others.

Having done well over a hundred sets of these early heads now, I'm pretty confident that its a sound solution and a good alternative to buying the late-model ones (with gaskets) when the current ones are still in excellent condition.