changing cam

[john910]

i'm changing my cam in a sbc from a hyd 501 lift to a mech. 587 lift , what is a safe valve to piston clearance? any help please. i will check the clearance with play dough.

[contagious]

safe bet is around 120-140 thou. on the exh. a little closer on the int. side.The piston is chasing the exh. valve closed.Be sure to check at 10-20 degrees before and after tdc.

[Tod74]

I've always been told .080-.090 on the intake .100 on the exhaust as minimums which is in line with the advice given above.

[contagious]

A lot of people will run much tighter clearances than i listed and do just fine,your right, give or take 15-20 thou. on what i listed,you should be just fine . Most off the shelf cams will be fine with no issues,but its all ways best to check.!!! 8)

[john910]

thanks i will check in the morning, thanks for your help.

[TS1955]

It's most critical is on the exhaust. As we all know the exh. valve opens as the piston comes up. We always make sure we have at least .080 with steel rods and .100 with aluminum rods.

TS1955