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john910 11-14-2010 02:58 PM

changing cam
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 11-14-2010 03:36 PM

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 11-14-2010 03:51 PM

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 11-14-2010 04:25 PM

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 11-14-2010 04:42 PM

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

TS1955 11-15-2010 11:02 AM

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.


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