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Any issues to be aware of replacing a single (cracked) piston in an LQ4?

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Old Jul 1, 2021 | 05:19 PM
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Default Any issues to be aware of replacing a single (cracked) piston in an LQ4?

Have one that was cracked and don't really want to replace all of them, it's a budget rebuild. Having a hard time finding just one used anyway, so might have to get a new one, which isn't that easy either. But really, just anything to be aware of or look out for as far as having issues replacing just one? Thanks!

And if you know of anyone that has a few laying around that would unload one cheap, please let me know...
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Old Jul 1, 2021 | 05:44 PM
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As long as it's the right piston, and the engine is otherwise sound, it won't hurt anything. It needs to be an LQ4 piston, though.
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Old Jul 1, 2021 | 06:10 PM
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I’d put a micrometer and check for roundness on a used one. As long as the skirt looks good I’d run it.
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Old Jul 2, 2021 | 03:18 AM
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Try Ebay. Is it a press pin or floating pin piston?

We bent 2 rods and damaged the under sides of the piston in the pin area on a turbo set up. I replaced both the rods and pistons with used units, re used the original rod bearings and rings out of their respective holes.

Still running strong.
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Old Jul 25, 2021 | 01:10 AM
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Thanks for the replies so far, appreciate that. I'm having a hard time finding pistons with a floating pin sold used as a single. From research it seems like the LQ9 were all floating, but only a relatively smaller (due to the production years available) number of the LQ4s had the floating pin setup. If all I can find is a pressed fit piston, can I reasonably run it that way, or no? Weight issues? It's not a crazy setup, cam, little head work IIRC (been a long time since it was built) to bring compression up, made 405rwhp, so probably 460 at fw I'd guess, if that makes any difference regarding balance or anything. Thanks in advance!
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Old Jul 25, 2021 | 01:29 AM
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I wouldn't be surprised if you could find a full set of Hyperutectics for less than one piston..
Assuming you have the motor out, in for 1 in for 8..

I've done singles on stock street engines, your power bump makes me wonder how you'd get the balance to match plus the new piston will likely have better compression so the firing toque could get wonky. RPM's are probably not your friend at that point.
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Old Jul 29, 2021 | 06:37 AM
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Look for more, further down the road.....
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