Originally posted by truckernix:
If you read the service manual, you will find a detailed procedure for adjusting the bearings. The procedure relies on removing shims until there is interference and then replacing one. Plastigauge works really well on a new assembly but it is not that great for a partially worn engine.
Well, yeah, maybe. If you have tapered or grooved bearings or journals, plastigage isn't too accurate. It's been a LONG time since I've messed with the babbit bearing system, but do use a micrometer to check the thickness of the shims. I seem to recall that they came .001, .002 and .003 and there just may have been .0015 shims available.
At any rate, I would "unshim" about .001 at a time. If you DO use the plastigage, don't rotate the crank after you put it in, just torque down, then remove the cap.
Real GM mechanics, please comment here.
