Originally Posted by TRChassis

Just wondering if anyone else has had an externally balanced 4340 crank balanced to internal specs and have the heavy metal fly out of the crank on the 11th pass. The machinist, if you want to call him that welded the piece into one of the normal balance drill holes not sideways on the counterweight like I have seen. Anyway the piece (1.5" long by 1.0" dia.) came flying out at 6,500 RPM through the pan, the diaper caught it but all 8 quarts of oil also exited and the motor seized, and is a total loss (BBC 496). The hole in the pan is almost 2.5". The machinist told me he had done many of those, and said we must have done something wrong. I wonder what we did wrong except for going to this lying, cheating machinist who took about 7 months to bore and balance our motor to start with. Any opinions?

Rick