Join Date: Dec 2001
Location: Belleville, Illinois
Thanked 22 Times in 17 Posts
Re: Piston slap
Piston slap is usually a wear problem, and not of great importance until it gets really bad. If it goes away within a few minutes of cold start, it's nothing to worry about. If it comes in and then goes away, even if the engine is warm, it's probably not piston slap.
And by the way, knurling the piston isn't necessarily a substandard treatment. The grooves left by the knurling hold oil, and piston wear and drag can actually be less than before.