2mm pistons...

Steve Robertson srobertson at ssimicro.com
Tue Sep 15 07:37:29 PDT 2009

I think you already have your answer but it all comes down to the numbers.
If they are high compression pistons you have to watch out for piston to 
clearance, piston to head clearance and final compression ratio. I put in 
high compression pistons that were designed for a Busa and ended up having
to stack base gaskets (not highly recommended) to get a safe squish number.
The valve pockets were deep enough that PTV wasn't a problem, but I still
ended up with +14.5:1 compression. I will be looking for some unmilled heads
this winter to lower that last number :-)

> Perhaps a dumb question but...but if one were to convert a SS motor which
> has had its heads machined for compression...they would or would not need
> new heads if they wanted to go the route of 2mm over pistons and things of
> that sort?
> Thanks. 

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