What are these doin in here??
 

Hey, I have a 89 930 with engine code 930/68. When I got to the pistons, I noticed that they are flat top Mahle pistons. Is this right?? Everything I've read and seen up to this point has had half dome shaped pistons. This concerns me since I have always thought the half domed piston design was inherent for proper combustion of the CIS fuel systems. Can anyone possibly help clear this up for me?

Thanks,
http://forums.pelicanparts.com/uploa...1096207811.jpg

I think the domed shape is only for NA engines. your turbo has lower compression and its not surprising to me to see flat top pistons.

stock 930. notice the exhaust valve contact notch.

Check out my rebuild pics, yes you have the right pistons in there.

Brian
Engine Rebuild Pics

Low compression turbo pistons will be flat or less than flat.

Sherwood

Brian,

I can't remember (forgive me, but I've been browsing the Porsche forums like a mad man for the past few weeks). Did you go to EFI on your build?

Yes, I went EFI. 431.8HP to the rear wheels and I am told there is more there with some more tuning on the computer.


Brian