[snbush67]

Originally Posted by PeteKz

Shane: Correct.

A couple years ago I wrote up about how to check valve clearance at overlap, because that's where the valves get closest to the pistons. You don't need the Stomski tool, although it's handy. Instead, I turn the valve adjusters down to make the valve contact the piston (gently), counting the turns. The adjuster screw pitch is 1mm, so every full turn is 1mm of valve clearance. I check both the #1 and #4 pistons at overlap because I want to be sure there aren't any differences from one side to the other, due to cam timing slipping or some defect in the cams.

In my case, using the M1 cam and the Mahle Sport 3.2 "10:1" pistons, my valve clearance at overlap was around .050". I have a tight clearance because the Mahle pistons are domed on one side without valve cutouts, and the M1 cam uses all the available lift and duration with those pistons, and I deleted the copper base gaskets to get a tighter combustion chamber and squish/quench (.030" deck clearance at the edge of the piston/cylinder/head).

You had 0.25" of valve clearance because the pistons you used have very deep cutouts. Those pistons are designed for racing engines with high lifts, much higher than what you're running.

Thanks Pete, I’ve actually mapped these cams with a degree wheel so I have that all taken care of. I’m not going to post it though because it’s William probably proprietary information.