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you may find this interesting

A class action complaint against General Motors Corporation was filed by the law firm Green & Jigarjian LLP and the Oklahoma based firms of Federman & Sherwood and Walker & Walker. The lawsuit, brought on behalf of purchasers of 1999 through 2003 model GM vehicles with a 3.1, 3.4, 4.8, 5.3, 5.7 (LS1), 6.0, or 8.1 liter engine that exhibits a loud noise due to Piston Slap

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I've owned an '01 LS1, an '02 LS1, and an '04 LS6 and none of these engines have slapped a piston or eaten an ounce of oil. Maybe people are just enjoying the engines too much and running the cars down the highway in 2nd gear? Or maybe they think their engine doesn't need oil changes or other maintenance?
 

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Forged pistons do that. (not that these engines have forged pistons, but the reasons behind the issue is similar) Since forged aluminum is denser than cast, it expands more when it heats up. Because of that, forged pistons are designed with more clearance when cold, so they heat up to the right size when the engine is warm. But since they're smaller when the engine is cold, they used to knock a little until they warmed up. Short skirt pistons like the ones in the engines in the lawsuit, have a similar problem, but because of the lower amount of stability that the shorter piston has making it wobble easier with the same amount of clearance compared to a deep skirt piston. It's not really a problem, and GM figured the lighter reciprocating weight was a decent tradeoff.
Another issue is that these pistons may have a different piston pin offset than earlier ones. Pistons usually have the piston pin location offset so that when the piston is at top dead center, the rod is at an angle which reduces a the slight binding that can happen when the crank, rod, and piston, are inline with each other, (in a sense, the piston can't decide which way to go) it's mostly a problem when trying to start the engine and at lower speeds. The tradeoff is that because you're not pushing the piston out as far, the actual stroke of the engine is slightly reduced. It's actually an old speed trick to install pistons backwards to change the way this works and gain a little power, but it does cause some noise when the piston changes direction at the top of it's stoke.
While the sound is annoying, it's not really a problem. The early ZZ series high output crate 350's used forged pins with no offset, because GM thought people would be interested in the extra power for their street machines. All the yuppies that bought them to stick in their street rods complained about the noise and the engines were actually recalled to stick hypereutectic cast pistons in them, with the offset pins. Even though there was no real problem, and the replacement parts weren't as good as the originals.

Class action lawsuits only benefit the lawyers anyway, the payout to the individual plaintiffs ends up so small that it's usually worthless. While the lawyers get their cut off the top, and the defendant has to pay a huge sum.
 
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