wrist pin clip issues

[Jeff Stout]

Originally Posted by Wayne Kerr

Ron,
You are going to have to trust me on this, and all the "experts" on here are going to piss and moan.
You need to have more pin end play. The reason the other engine opened up to .035" is because that's what it wanted. The pistons deflect from gas pressure and the pin bosses flex inward. We built a fixture and we put 1500 psi nitrogen on top of a room temperature piston just to prove this fact. Lost numerous cup engines and a few IRL engines as well, with too tight of wristpin end play.
Wristpin end play is like bearing clearance, too much and you know about it, too little and everybody knows about it.

See you at the races,
Wayne Kerr

What would be the desired amount of end play on a medium performance engine 150 wall 153 gram, and 545 gram piston, 3.385 stroke? I have .027 right now