I will be running Wiseco forged pistons in my new motor (not the HD's). What do you guys recommend as far as piston to wall clearance? .004? I plan on running either an FP Red or BBK turbo (400-450whp) and maybe switching to a GT35R on track days.

Also, WHAT is the CORRECT method for measuring this clearance? Most people recommend measure the bore (90 degrees from the crankshaft center line) and then measuring the diameter of the piston (90 degrees from the wrist pin, somewhere on the skirt) and subtracting the diameter of the piston from the bore diameter. Should this value be divided by 2 or not?

 

Call Wiseco. Ask for Brian Nutter. Give him your engine specs and ask for their recommendation. Different manufacturers use different materials with different expansion rates.

 

best way to measure is with feeler gauges. measuring bore and then piston leads way too much room for error. I put the piston in upside down and slide feeler gauge down side of skirt . very simple very effective. for those who who use multiple measuring method because it seems more professional, dont knock my method before you try it. feeler guages are very flexible at this thickness.

I recommend .005 minimum. seen way too many forged pistons/bores ruined set at .0035-.004.

 

double post, not double important

 

bringing this topic back because i am about to build my motor as well and was wondering the same thing. ive built a few chevy 350's and i usually like around .0045-.005 but not sure on the evo motor.

 

I have JE pistons running .004