piston to valve
TECH Resident
Joined: Aug 2004
Posts: 875
Likes: 2
From: Portland Oregon
The standard for race motors is minimum .080 intake and .100 exhaust. I would be surprised if it was any less than that. But, I have been surprised before, and everyone has a different opinion about how much clearance you really need. If you have ever been at WOT when a piston kisses a valve, you will learn real quick about why clearance is important. I always ask for more than .100 when I buy pistons.
When I measured mine at TDC the intake was 0.357" and the exhaust was 0.380". It will be slightly less when the valve events are closest during overlap somewhere around 15 degrees or so BTDC and ATDC so this should give you an idea that there is a LOT of clearance!
