[SE-Rawkus]

This is an interesting topic I found over on Honda-tech and figured it something we can all discuss and learn from....

How does skirt coating affect piston to wall clearance?
"CP calls for .0035" clearance. Right now my pistons are 3.3060" with my Swaintech PC-9 coating and my bores are 3.3085" leaving me with only .0025" piston to wall clearance instead of the recommended .0035".

Will .0025" be enough to run on a high boost car? If not, I can open up the bores another thousandths but then what happends if/when the skirt coating wears off? Then my clearance will be too much. The coating is approx .001" thick on each side.

Someone also suggested with the gold coat thermal coating my pistons tops recieved, they may not heat up and expand as much. Meaning they will not need as much piston to wall clearance."

Please discuss.....

 

[MIXMASTAP2]

a peanut is neither a pea nor a nut....discuss amongst yourselves

 

[UK-SRi]

Look on se-r.net, one of the rebuilds on there they mention running less clearance when coated, the coating has compliance, unlike the piston...

Mike

 

[LanceSR20]

tighter piston to wall clearences due to pc-9 coating or my skirt coating, is not to be worried about. if without coating, the piston to wall clearences are within specs, then it will be fine. you see pc-9 and the skirt coating that i do, give under wear. and will return to the right tolerances in the right places after the motor has been running for a little while.