Clearance between Piston Wall and Piston?

[bullet@TheBeach]

What should be the clearance between the piston wall and the piston? I need to know ASAP. The block is at the Machine Shop having 40 over pistons put in and the guy needs to know what clearance they need to be before he bores the block. thanks.

[Florida240sx]

Think my clearance was .002 then after crosshatching it was .004...You get the pistons new? Because your pistons come with a spec sheet on what the bore should be. Call the company that makes your pistons if this sheet is lost. .002 os an inch can determine your motor lasting 80k-200k

[WDRacing]

Things vary with piston type and material as different materials expand to different thicknesses. My pistons came with a spec sheet also.

WD

[WDRacing]

I just checked JE's site, they recommend a .040 clearance. Thats diameter minus diameter for a total of .040.

Here's a good link for the pistons Ross makes. http://www.rosspistons.thinkhost.com/downloads.php

[Florida240sx]

that can't be right.... it has to be .004....unless your saying .040 over factory bore.
Modified by Florida240sx at 7:48 PM 8/28/2006

[virus77]

cast pistons usually run .002

Forged slugs usually ask for .004

[bullet@TheBeach]

The problem is that I ended up with a bent rod that had slapped the piston wall and put a good dent in it near the blttom. Then after the rebuild the oil lands on all 4 pistons cracked while it was on the dyno on the first run. So there is some marks on the walls that need to be cleaned up. He thought .20 over might not clean it all up. I could not find another block, so I have to go this route. Ten some guy told me that the clearance needed to be different for a car that is boosted than a car that was not. I was just checking to see if that was true.

[lrb_2000]

This is what came with my supertech pistons.
Modified by lrb_2000 at 8:59 PM 8/28/2006

[bullet@TheBeach]

Thanks, that should be just what I am looking for.