Update. For all of you that said bore seal, you were right. Valve guide issues as well.
I spent a day in Greenville TN With Bob at Performance Automotive.
He did a lot of work on Allan Johnson’s Pro Stock project. The first thing he did was run a bore gauge in the cylinders. The block was bored and finished honed when I delivered it to the first shop. I have the receipts from Diamond Racing. The pistons (Diamond) were 8032 alloy, fit at .003-.0035.
So why was there an obvious cross hatch and a measurement of .007-.0075? The first shop obviously didn’t think there was enough clearance?
The intake guides were round, no taper and measured .0015-.0017. But the exhaust were round and straight but .006-.0065?
So, DOUBLE the ideal clearance on the pistons, causing ring failure. The extra clearance in the guides didn’t help either.
I don't know of ANY ring that will seal with 100% or more clearance. Why guys don't believe what the piston manufacturer says for clearance isn't enough. I mean...if an extra .0005 (half a thou) doesn't keep the piston from sticking in the bore, nothing will.
That excess clearance is a ring seal killer. I still believe that a coating from Line 2 line would have fixed that issue.
And guides with a clearance like socks on a rooster won't help either.
