My local engine machinist was a bit suspicious about cylinder hone sizes when honing stock 3.898 bore LS6 block for JE forged pistons. He says the hone cut is strange much for a "standard" piston size. JE piston install guide recommends piston to cylinder clearance 0.0045. Piston diameters are measured 3.896 - 3.897. All cylinders are 3.898. So hone cut should be about 0.0035. I know LS6 block is safe to hone as much as 0.01 in some cases. But Is this much hone normal for forged pistons? Piston product number is 321239 Machinist ask me to check piston cast numbers for make sure there is right pistons in the package.

 

That .001" variance is pretty large for a company like JE. I have yet to measure a factory block that isn't .002'-.003" larger than "standard".

What is your machinist measuring with, a dial caliper?

 

All measures are taken with micrometer. I rounded up little when converted measurements to inches. I live in Europe so exact results are in millimeters. Pistons: 98,97 - 98,99mm
Cylinder bores: 99,01 - 99,02mm