Piston to Valve Clearance? [Archive]

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RickR

02-05-2002, 08:20 AM

What is the minimun piston to valve clearance for a nearly stock 5200RPM max BBC Mag?

You FLA guys are killing me! I am going to get Genuine Risk out of the corn crib today. Change the bildge pump leads over (Thanks Madpoodle) and drop the engine in on Thursday.

RedDog

02-05-2002, 09:40 AM

Yep - better switch those bildge pumps leads over - that way you'll pump the water out instead of in biggrin.gif

Gearhead99

02-05-2002, 05:34 PM

You should run a minimum of .100 valve to piston clearance.

BigGrizzly

02-05-2002, 07:30 PM

Mine is set up at 0.030 intakes and 0.060 exhaust and run it to 5,700. And mine is a blown with 9.25 flat top pistons. Most Cam specs give you the clearance numbers, mine are pretty standard
Randy

RickR

02-07-2002, 08:10 PM

FYI
http://www.gmgoodwrench.com/crate_engine/engines/big/torq2.html

DONZIMAN2

02-07-2002, 08:30 PM

Grizz, That is pretty tight piston to valve clearance. The tightest I ever went was 80 thousands on the intakes and 100 on the exhaust. When we ran the 4 speed I liked a little more. BOB

turbo2256

02-10-2002, 05:54 PM

I have to agree with donziman2

turbo2256

02-10-2002, 09:53 PM

BBC are famous for no 7 cyl clashing piston and valve

Klingon

02-10-2002, 10:27 PM

The minimum that you need is 040" That number has served me well. This is assuming you are running springs that are suitable for the cam and rpm. 040" also is the clearance between the piston top and head.
Alan
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