With the new BTR canted heads on the way im going to flycut my wiseco pistons. I've already got a lindy flycutter for a 2.08 valve and it measures 2.153" the new heads will have a 2.125 valve. My question is, .028" enough clearance for the valve?
I know its really .014 clearance with the valve edge and piston cut area.

 

You won’t actually know your radial clearance until after you’ve cut, and measured with clay. I want to see .04 minimum radial clearance. It’s important to allow for thermal growth and potential valve head movement.

 

I fly cut my pistons a few years ago and found not enough radial clearance in the pocket as well. What I did to fix it was to chamfer the edge of the cut back by hand with fine cut carbide burr to get the needed room. It was pretty simple to do, just need a steady hand and take it slow. Just make sure you don't leave any razor sharp edges behind as they will create stress risers and potentially a hot spot.

 

What fixture are you going to use to flycut the pistons? Unless you're using the canted valve head itself, won't the pockets you cut be in the wrong places?

 

I can do that. I do have plenty of burrs here back when i used to port heads.

 

When i measured the cutter, it just seemed it was going to be tight.