Quote:
Originally Posted by lust4speed
Seriously doubt any of us could hear noise from a piston only .002" out of spec. The "recommended clearance" of .003-.004 and being at .006 just isn't that critical of difference. Thousandths definitely matter in bearing clearances, but are we are overthinking this on piston clearance when we're talking half the width of a human hair?
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I agree fully with this statement, I've put together engines that were a couple thousandths more piston clearance than the manufacturer called for with no negative results at all.
These were on oval track engines which can tend to run hotter than a drag strip engine, or most street engines. With tight piston to wall clearances you'll be scuffing the skirts of the pistons and transferring metal from the piston in a hotter operating range. The little bit extra clearance is a little insurance in an overheat situation, but in normal operation the extra clearance is negligible. I wouldn't worry about that small amount.
I don't think you'll have any piston slap at startup, but even if you do it's nothing to worry about, my 2005 LS2 GTO (LS engines are notorious for piston slap when cold) has piston slap when cold, and has had since it was almost new. It now has 140,000 miles on it, and no problems, and it's about the same as it was at 20,000 miles when I first started hearing it.