Quote:
Originally Posted by Hitman
I actually, fully understand knurling, but you personally don’t know me, so I’ll assume you are not talking to me directly. Knurling is outdated technology from the time when new pistons were of poor quality when compared to oem pistons. Today’s new pistons for model a’s are of superior quality for 95% of the users out there. For the same amount of effort, time, and cost, why wouldn’t you go with new rings and pistons?
Piston slap is the result of one or both things, either the piston collapsed, or the cylinder is worn enough to taper, allowing the slap. The real solution is new pistons, or bore/hone to the next size AND new pistons.
Knurling is a bandaid. It’s one best applied by the old total seal (or others) knurling machines. Far more rare and expensive than a new set of pistons.
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You are correct, I was not talking directly to you or anyone else, just in general from what I found during my earlier research. I agree with everything you said with one exception and that is that there is a 3rd cause for piston slap and that is a bore that was bored with too much clearance. In this case, when the bore is too big but not tapped, knurling is, IMO the preferred solution over reboring to the next size and getting new pistons. In my particular case, my pistons had quite a bit of slop and there was zero ridge at the top of the cylinders so I assumed that the bores were just bored too much by whoever built it last in which case knurling would have been the answer. However, once I mic'ed the bores and found the taper I was only left with two options. Bore them to the next size or sleeve the cylinders and start from stock. I chose to hone the cylinders to the next size myself.