Hi all!
I'm the machinist on this job, and it's getting a little frustrating! I've got 45 years in the trade, ASE master rated in every category they offer, 22 certifications in all, including Master Machinist! The original block was bored .060" by a local shop, and was not, in my opinion, done very well. Among other things, the main bearings had not been align bored, and the bearing clearances were incorrect. We repaired that before the first assembly job. The piston was badly scored and the wrist pin was tight on the first teardown. I sleeved the #1 cylinder, fitted a new piston with a little extra clearance, and got about the same mileage as before when it tightened up and scored #1 again.
Got another block, sleeved #1 due to excessive wear, and bored all the holes .030" Speed-Pro Hypereutectic pistons this time, for a 307 V-8. (Same dimensions as a 250, but flat top, not dish top pistons.) I'ver done this before on several engines with good results. Milled the intake manifold for a leak-free fit to the head. Milled the head .050" also. Performance increased dramatically, but it's knocking again, haven't done another teardown yet. I build roundtrack race engines, 600 HP or more, and they stay together and win races! Am I missing something here?
Jerry
