On an LS motor has anyone ran a 8 thousandths piston to wall clearance? What are the disadvantages to such a large gap? Thanks, Brian

 

That is really large. I would look to run .004" piston to wall clearance on an LS block.

Nate

 

.008" is too much clearance, even for a forged piston. I believe the motor will still run and probably seal just fine, but the cylinder may wear faster due to the excessive clearance allowing the piston to rock around. Definetly not a good thing.

 

The rings and the cylinder wall will take a beating. If broken in properly it will make good power for a short while and then fade as the rings go away.

 

In the old days we had to run larger clearances like that because the forged pistons expanded a lot now they have alloys that do not expand so that is not going to last very long as the guys say. I used to have a gto (1964) and I would rebuild it every 10,000 miles...it went like hell though.