<snip>
Cause: the forged PE pistons have lower silicon content than
cast pistons (from ECI, for example) and have a higher expansion coefficient
than cast pistons. When installed with insufficient piston to bore
clearance, the forged pistons rub which also scores the cylinders. . . .
Should PE have used
additional bore clearance for the high compression pistons? Of
course. Somebody screwed up and used the wrong clearance
spec. <snip>
I believe that 100% of Performance engines are shipped with forged
pistons. That is one of their trademarks of their build (that and late
delivery). So I find it strange that they used the wrong clearance.
All their engines should be sized for forged pistons and there should have been
no choice to be made during assembly. I wonder if they jobbed out
this work to another shop.
Robert M. Simon
ES-P N301ES
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