Quote:
Originally Posted by seningen
Nice plug for the junk yard :-)
What is allowed in an engine rebuild? Can you custom make the rings?
What limits are there on the valve job.
IMS retrofit isn't going to get you anything.
Anything else would seem to be illegal.
What weight oil do you guys run?
Could you alter the cam to exhaust timing on the vario-cam by displacing a tooth and still not have interference but gain anything?
Note I don't race spec boxster -- but I've been involved in a few M96 rebuilds and its not hard to accidentally alter the vari-cam timing during install (but I've always caught it :-).
Mike
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Yeah, some of the high mile motors run good after being loosened up!
There aren't very clear/good/complete rules when it comes to the rebuilds like you would find in Spec Miata or a class run by a more professional organization, unfortunately. So the term "stock spec" really covers most of your questions. At the least, we're trying to make sure everyone is using stock components.
We're supposed to be using stock Porsche pistons and rings. No aftermarket pistons/rings built to same size or anything like that. I have not seen limitations on valve jobs, other than the valves need to be stock.
Oil weight is up to the competitor/engine builder, there is no stock spec. I use 0w-50 Mobil 1 Racing oil.
You cannot legally alter the cam timing. However, I'm sure there are some that do. It is not something I've done or experimented with so I can't speak to the specific advantages.