What are these doin in here??

[CreatuR]

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,

[jpnovak]

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.

[john walker's workshop]

stock 930. notice the exhaust valve contact notch.

[briankeithsmith]

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

Brian
Engine Rebuild Pics

[911pcars]

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

Sherwood

[CreatuR]

Originally posted by briankeithsmith
Check out my rebuild pics, yes you have the right pistons in there.

Brian
Engine Rebuild Pics

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?

[briankeithsmith]

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