On my race engines, I don't trust Plastigauge. I torque up the rod and main bearings with the crankshaft removed, and measure the actual inside diameter, down into the .0001" range, then measure the crank journal and subtract the difference to get the clearance. Then I polish each crank journal individually to get an exact clearance on all the bearings.
Jerry
I have no doubt YOU possess the skills to use measuring tools correctly but in supervising a bunch of machinists who constantly swear thier tools are used and calibrated properly CMM inspection continually proves otherwise. For the average person plastigauge eliminates human error and is readily available to anyone at low cost.
