Hmmmmm- - - -too bad General Motors didn't have a bunch of engineers back then who knew how to make engines out of aluminum foil instead of precision-machined cast iron! Think of all the money they could have saved!
Simply distorting the bearing at the bottom to make the Plastigauge look good is the equivalent of a doctor giving his patient a sugar pill and convincing him that the thing is going to cure his sickness. It's called a "placebo". It's a common practice when treating people with imaginary symptoms. I would be interested in seeing bearings that get the tinfoil treatment clamped up without a crankshaft in place, and accurate (like down to the .0001" range) taken all the way around. Yes, I've done that when building engines that were producing three times the factory rated horsepower, and the results are surprising at times. Also try measuring cylinder bores with a torque plate installed sometime! They are anything but round.
Jerry
