Piston skirt damage

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1972ho
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Piston skirt damage

Post by 1972ho »

The damage that is done to the skirt on the piston going to have any effect on how it will seal,and is it usable or can it be cleaned up and used.
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BillK
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Re: Piston skirt damage

Post by BillK »

How does it measure ? That is probably the most important thing.
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Mark O'Neal
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Re: Piston skirt damage

Post by Mark O'Neal »

I'd turn the tangs off, measure it and run it.

What's the black stripe?
1972ho
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Re: Piston skirt damage

Post by 1972ho »

That black strip is just the shadow of the oil ring groove,and measure the same as the rest of the pistons.
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MadBill
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Re: Piston skirt damage

Post by MadBill »

Is that a ding in the top of the second ring groove at ~ 5:30?
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Re: Piston skirt damage

Post by xanadu »

Ring lands look to be pretty beat up
1972ho
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Re: Piston skirt damage

Post by 1972ho »

Nope’the rod across from it broke and some little fragments bounced around and hit it,I have gotten another piston for the engine I just thought I would see if you all thought this one may have been ok.
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Re: Piston skirt damage

Post by jake197000 »

i wouldnt use it
makin chips
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Re: Piston skirt damage

Post by makin chips »

1972ho wrote: Tue May 14, 2019 6:18 pm That black strip is just the shadow of the oil ring groove,and measure the same as the rest of the pistons.
I figured he meant the vertical stripe. What's with that one? It's the one that obviously looks out of place and could not be mistaken for a harmless shadow. If that vertical stripe is also a shadow, there's issues there, either way. We all know it wasn't manufactured that way, whereas it's pretty easy to figure out that's a shadow on the ringland at the "bottom".
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Re: Piston skirt damage

Post by mag2555 »

If the ring grooves measure consistent and the rings can spin freely I would give the skirts a light polish with 600 grit paper and ATF to lube the polish work it and then run it.

What did the rod go south though?
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Re: Piston skirt damage

Post by novafornow »

mag2555 wrote: Wed May 15, 2019 6:17 am If the ring grooves measure consistent and the rings can spin freely I would give the skirts a light polish with 600 grit paper and ATF to lube the polish work it and then run it.


I am with this. Depends on whether it is a bracket car or something that is run harder. Personally, I probably have run worse.
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Re: Piston skirt damage

Post by allencr267 »

When you've polished off the skirt's high spots, the few grooves don't matter(a little extra lube reserve :wink: ), what's the clearance? Decide what's looks/cosmetic & what's necessary for ring seal and the skirt's load against the wall.
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MadBill
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Re: Piston skirt damage

Post by MadBill »

If they're a little loose but otherwise okay, you could have the skirts abradably coated by Line2Line or a similar process: https://www.line2linecoatings.com/
The circa 1970 TRW pistons in my 495" BBC had 0.008"-0.010" clearance after torque plate honing. L2L built them up to ~0.000". Haven't run it yet, but I have every confidence they'll be good..
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Re: Piston skirt damage

Post by TAM »

Measure the piston. With the lower skirt dinged up like it looks, most likely the skirt is collapsed.
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Re: Piston skirt damage

Post by hoodeng »

The guys promoting measuring the piston are on the money, that bottom third of skirt band i have found in the past to be a sure sigh of a collapsed skirt to the point in worst cases the piston taper has been inverted.
CP can give you the original shape dimensions to check to.

Cheers.
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