Thanks all for such quick replies...
Surf... It is leaking. The kind of leak that leaves a pretty heavy mist on the back of the car just after putting 30 miles on a fresh wash. So much so that it has a pretty constant drip off of the crankcase right after turning it off (Granted I am running 0-40w Mobil 1 in August in So. Cal.). At $5.00 a bottle I will be able to pay for a new engine soon!!!! Porsche would have put a time limit on the warranty and 13 years is probably way off, at my best guess.
Max & Bill... Thanks for the breakdown. Bill you note that they are listed as 91-... Do you know the part numbers for a 90? Either way, Does it matter which set I get? and How do I tell? Those part numbers come as a complete set so I would get all 6 pistons/cyl. etc. for the price.
In my case, Bill, I have 3 leaks (1 is easy to fix).... Cyl. 1 & 3 are leaking at the base to crankcase and 2 is leaking at the head to cyl. and then I have the valve cover gasket leaking on the back of three by the knock sensor. How do I know this you may ask?For the record, I have washed the engine, parked it and jacked it up. I can re-clean it off every couple of hours and then see droplets forming at the various spots mentioned. It's a real heartbreaker!!! You mentioned the 102mm set was similar in price. For the record I can pick up the part that ends with #25 today for $2,072. How does that compare?
Bill, the way I read everything I have ever seen on this subject, is that the base of the Cyl. has to be machined for the grove, not the case. I would assume that if you machine both pieces you would need a real large 'O' ring to fill this space.
The real pisser about all of this is that this car had a valve job 26,000 miles ago!! Now that I have a much better understanding of how these engines are constructed, I can tell from the invoice that cylinder updates were not paid for. The previous owner probably didn't know about this issue and his regular garage doesn't appear to specialize in these cars. They probably put the car back together just like they took it apart without ever accounting for any changes that Porsche made along the way(except for new valves and a re-facing). On top of that, he paid $5,000 for the job. Well, I guess I am into this car for the next 10 years. Might as well make the best of it!!!
Darin