Originally Posted By: A_Harman
My 2002 LS1 Camaro has had piston slap since I bought it new. I was pretty disgusted with it, and thought "OK, I've got a 36,000 miles warranty, I'm gonna drive it like I stole it, then bring it back for a new engine at 35,000." I thrashed it mercilessly at autocrosses and track days for 2 years, and the cold start slap never did get worse. So I didn't worry about going through the warranty without replacing the engine. Now at 263,000 miles, it still behaves as it did when it was new. Once it warms up, the engine doesn't have any mechanical noises. But it burns oil now, and I have retired it from track days after accumulating ~200 hours of track time in 15 years. The oil consumption didn't become unacceptable until it had over 240k on it.
One thing I found that helped the cold start piston slap was to rev the engine to 1700 rpm instead of letting it idle. The slap noise would go away. Then once the engine got to operating temperature, it ran silently at idle.
I ran a lot of different oils in it, but none of them had any effect on the piston slap.
That is awesome. Glad it's still on the road.