Could these pistons be reused?

empera

empera

Authorized Vendor
Mar 30, 2005
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supposably they are .20 JE's...rodknock on the #1 rod. car was ran rich as hell reason why theres so much build up. wondering wat u guys think...

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i have new rods to put on them if i do decide to reuse em, depending on wat some of u guys say.
 
Keros

Keros

Canadian Bacon
Mar 16, 2007
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crrider80 said:
Don't place them on your concrete floor.
-Steve
Click to expand...

Yep.

Letting them touch or sit on anything that is potentially harder than the piston can cause microscopic (or macroscopic) damage to the surface finish, especially on the edges... then when it's run in the motor it'll leave a nice groove in your cylinder wall. Minor? Yes. Easy to avoid? Yes.

Put them on the new towels your wife/gf just bought :biglaugh:
 
p5150

p5150

ASE and FAA A&P Certified
Mar 31, 2005
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I dont know how deep the scuff is. You could have them polished a bit and re balanced at a machine shop.

I think you could still run them if they come out relatively smooth without protruding edges and are still round. In stock form they arent smooth to begin with so dont try to make it perfect... The side wall has minimal contact with the cylinder wall and needs to have a certain roughness to keep oil on it. If I was going to use them I would get them cleaned up and checked for out-of-round. Check the piston wrist pin holes for elongation too. Look for impact damage on the top of the piston where it may have hit the cylinder head when the rod was knocking. It should be pretty apparent if it has.

Once you have them cleaned up and verified round you can have the skirts moly-coated. This should help eliminate any inconsistancies on the skirt and keep the oil sticking to it.

FYI, the generic "lubricant" from wal-mart works great for cleaning that carbon off.
 
suprarich

suprarich

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Nov 9, 2005
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I have repaired pistons that look worse and reused them with new rings, but they did not last very long. If it was my motor, I would just get new pistons. You will lose a bit of skirt to repair those and may have a bit of slap after. Repairing and then coating them may make up a tiny bit, but then you are throwing money at a dead horse.
 
p5150

p5150

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Mar 31, 2005
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one thing though rich - the did not come out of his motor. He can bore the block he is using to properly match the pistons after repair. He shouldnt have any slap.
 
D

Doward

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Jan 11, 2006
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Oh, I missed they weren't out of his motor - p5150's right, then - you'll end up with like a .015" bore, but it is very possible to clean those up and re-use them.

Verify they are round still, though.
 
D

Doward

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Jan 11, 2006
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IJ. said:
They shouldn't be "round" to begin with....... ;)
Click to expand...

LOL, you know what I mean - verify no excess elongation afterwards (generally perpendicular to the wrist pin has a slightly shorter diameter than across the pin, due to the greater mass (and greater expansion) of the material around the wrist pin)

Hence the 'too little piston-wall clearance' comment ;)
 
D

Doward

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Jan 11, 2006
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Yeah, I'd also like to know the conditions the piston was put under. The ridiculous carbon buildup more or less shows it was a less than stellar tune. I'd be interested in knowing the piston-wall clearance used, and the settings under which the piston was run. Pure academia, but it'd make for good discussion, I think :)
 
I

IJ.

Grumpy Old Man
Mar 30, 2005
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I come from a land down under
The carbon looks more like a Cletus PCV mod to me.

I run my JE's tight (3 thou) but they haven't even scuffed the coating after 6000 kilometres (5k of hard thrashing) and an intake explosion that would make the Mayor of Hiroshima duck.
 
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