Hap Waldrop
Yoda
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I thought I would start a new thread on this subject rather than hijacking one of the existing threads. I know Jack is getting ready to do this, so I thought now would be a good time to go over this. Plastigauge is a decent way for the average DIY engine builder to check clearences, but if you don't have alot of experience with this product, much can go wrong to askew your readings.
Checking the mains is easier because the crankshaft has much less chance of moving, the rods are much harder to check because while torqueing and lossening the rod bolts it's real easy to move the crankshaft and if the the crankshaft moves then your palstigauge reading are useless. So the big thing with palstigauge is too make real sure that nothing moves during the process and great care is take when removing rod and main caps, doing it a couple of times is a good way to double check yourself. If the crankshaft moves while you're plastigauging, then it will smear and this will make you think you have less clearence than you really do have.
Jack if you didn't have your rod's big ends resized, then by all means atleast have a machine shop check them.
FWIW, I build all my street engines to .0015" on rods and mains.
Checking the mains is easier because the crankshaft has much less chance of moving, the rods are much harder to check because while torqueing and lossening the rod bolts it's real easy to move the crankshaft and if the the crankshaft moves then your palstigauge reading are useless. So the big thing with palstigauge is too make real sure that nothing moves during the process and great care is take when removing rod and main caps, doing it a couple of times is a good way to double check yourself. If the crankshaft moves while you're plastigauging, then it will smear and this will make you think you have less clearence than you really do have.
Jack if you didn't have your rod's big ends resized, then by all means atleast have a machine shop check them.
FWIW, I build all my street engines to .0015" on rods and mains.