Quote:
Originally Posted by im4duke
I am rebuilding my 3.3 turbo engine and using new Mahle C2 Turbo pistons & cylinders. One builder suggested that I machine reliefs in the pistons to insure against piston/valve contact. I will be purchasing upgraded valve springs as well, though have not yet decided whose to buy. I forget what he quoted to do this work. I know it is common on aftermarket pistons. Any opinions on whether I should do this?
Incidentally, a bent exhaust valve is what ultimately led to this rebuild...
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Bent exaust valve is typically from a missed shift or failed tensioner.
If you are using some wild cams this may become necessary. Test fit should be done if that is the case.
There may be something special about C2T P&C's on a normal 930 as they had sealing rings at the head and something different at the base. I do not know if this means ther is some shimming to get the stock height right but I do not know about this. Check w someone that knows. However, this should not effect the valve clearance.
930's are what they call an interference motor. However, cutting reliefs is not typically done for just insurance reasons.