What is the piston to cylinder wall clearance for JE pistons?

[gnx7]

I have a set of used JE pistons from my old engine that were overheated and one piston transferred aluminum to the cylinder wall. Not good.... I know.

So I'm building another shortblock and want to see if any of the others can be salvaged. They have about .007-.008 clearance measured with a caliper (horseshoe shaped device) on the piston skirt.

The worst one measured .018 clearance and it was a .020" overbored block.

I'm pretty sure these tolerances are too loose.... but don't forged aluminum slugs expand more? What if I had the skirts dry film coated to take up some of the clearance? Is this a waste of money?

Do I have 6 matching lightweight ashtrays now or what?

I just don't feel like spending another $500 if I don't have to.

GNX7

 

[Intercooler]

Get some Hypers Honestly I think you might as well toss them if you can't get between .004"- .006" piston to wall.

 

[Monty]

On all the sets of JE pistons I've had, they recommened either .005" for naturally aspirated, and .0055" for forced induction. In both cases, measure it .500" down from the bottom of the piston skirt. This was on SBC pistons though.

 

[Steve Wood]

do they specify 90 degs to the pin as well?

 

[Monty]

The measurement is .500" from the long side of the skirt, which is 90 degrees (perpendicular) to the pin.

 

[ijames]

Only being half sarcastic here - if they are 0.018" undersize for a 0.020" oversize block, get a standard bore block and hone it.

 

[gnx7]

If the specs call for .004-.006 and mine spec at .008...

Is it a waste of time to have the skirts dryfilm coated to take up the extra clearance?

When I took the engine apart with these messed up pistons it was not smoking or consuming vast amounts of oil at all!

GNX7
(cheap bastard who doesn't wanna spend $500 on new pistons)