So we have a 01 turbo here, low mileage and well out of warranty. It has had a nagging leak for a while. Owner finally shipped it to us and said please fix it. The dealer never could. I determined that NOTHING on top or bolt on externally was the culprit and would have to go in.

So what I find was this! This is the head gasket. The head and the cylinder base where the gasket resides. The gasket itself had an imperfection in the middle of it. The gasket is a three ply setup that has two outer skins and a crush gasket in the center of the two. The gasket has a imperfection in the middle layer. A fragment of gasket from being stamped I suspect. The end result is it pushed up on the outer portions of the gasket and in to the head and cylinder base. It sat there pressing and pressing until it indented the head and the cylinder base. One impression is about .5mm and the other is about 1mm. Made one hell of a mess and is the first time I have witnessed something like this on all the 996TT motors I have built. Which have been a lot to date.


Thought I would share.
This is the outer skin to the head


This the cylinder base

This is the center gasket

This is the head

 

Sad how the dealership couldn't diagnose their own cars...you da' man Stephen!

 

Yikes. How much to fix?

 

Termites?????
Can probably weld/mill it down.
I still know a couple of high end NASCAR quality machine shops in the KCMO area if you don't have a machinist locally who can handle the job. Good catch!

 

A lot. Figure I have to tear down the whole side of the motor down to the case which means pulling the pistons. Now the head and cylinder base will need to be faced and the cylinder edge cleaned up to meet the base's new deck height. Probably about 5-6K by the time it is all done.

 

Isn't this the sort of defect that (so clear and well
documented) Porsche might consider paying for some of it?

Joe Weinstein

 

Did the customer begin the complaint process
for this issue before the warranty ended?

 

Very good question. Many other marques the mfg will wind up footing the bill, but not without a fight.

 

good ol' porsche... i feel sorry for the guy, especially since it sounds like he hasn't modded the car..

- chuck

 

Great work again Stephen. I know where my car is going when it gets a big ouch!

Good luck trying to get P to pay.

 

ouch.... that us pretty wild.....

 

YOU know, while he has the engine apart anyway . . .

What's his e-mail address? This would be a good time for him to join the 6 . . .

 

WOW, that sure is interesting, we have never seen anything like that before. Have had a couple of leaky cylinder base gaskets, but never that. But, then again, these cars never disappoint in the "never thought I'd see that" arena.

Kevin

 

How well balanced is the recriprocating mass as it comes from the factory? Is a mm , or so, off the decks of 3 pistons going to create any problems? I am just making an assumption that you would also cut the piston decks to keep the static compression the same on both banks. My engine-building technology is about 20 years outdated so it may not make any difference these days.

Do you routinely have the assembly rebalanced when you swap out for Carrillo rods and after-market pistons?

 

I have changed my mind. We are not going to deck them. Better I will tig it up and send it out to be redecked to factory spec. This is probably the best way to do it.

Most of the assemblies are fairly balanced, however when I build motors I am not doing what the dealer does, pulling apart and replacing then putting together. You will find in this industries most people are assemblers. They simply pull apart and put the new parts in and that is it. True engine building these days is near unheard of..sadly. We still build apx 5-8 motors a month from all years.

We spend a fair amount of time balancing everything, dry assemble and measure and tear it back down, check the specs and reassemble when all the specs are were we want them. This makes for longer engine build, but catches issues that are "ok" by factory trained mechanics and not in the real world. Like the thrust issue which is not an issue according to Porsche.

In all we balance and blueprint every motor that we build. I am probably a dieing breed