Quote:
Originally Posted by dsmreck
the reason you want pistons b4 you bore is each piston may have a variance. so 20 over what? stock bore or where it was or to a .20 over piston. you may end up with a .20 over piston that has hugr piston to wall because not all things are perfect.
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I can't quite understand what you're getting at here, but .020" over means beyond the stock bore, on these engines, and every other one I've ever heard of. If you want to get technical, "import" motors such as these go by mm instead of inches, so it's actually .50 mm over. Same thing though.
Every time I've had machine work done, my machinist measures all four pistons, takes the largest one, and adds the appropriate PtW clearance for all four holes based on that. PtW clearance is based on the piston material, or manufacturers specs for aftermarket, and I used to go even a little looser than that back in the day. Boring each hole to exactly the same PtW clearance for each individual piston is way overkill.
Trust me, the machine work we have done for these is generally better than what the factory ever did, and those engines lasted 150-200k miles and have withstood 500+ horsepower. Having a couple ten thousandths variance in PtW clearance is the last thing I'd worry about in a rebuild.