I am wondering what the diameter of a piston, at the top should be that is in a 4.030 bore LQ-9 block. I was under the impression that the difference between the cylinder bore and the piston should be under .005 I have my heads off and am looking at the pistons and deck and it appeared I have alot more. This was confirmed when I got my feeler gages out and could put .019 on one side and .018 on the other. I'm thinking these pistons are for a standard 4.000 bore not my 4.030 bore

 

Different pistons will vary, but .030 under at the point above the top ring is very normal.

Kurt

 

Thanks Kurt. I was going to take a piston out and mic it up but I'm having trouble getting the dampner bolt out and want to do that first. I hope to be bringing it up next month