Yesterday I stopped by the machine shop to see if the sonic test results were in on the 312 block. The shop owner said "there are a couple issues, and this is your crank". Reaching down he picked up the snout, with only the first counter weight attached! My nice new ground 20/20 312 was broken!
The crank was in its plastic sack, standing upright when he left the shop on a Fri. a month ago. On the following Monday AM it was on the floor. He bent down to pick it up, in two pieces. In the many years in his business it had NEVER happened before, and he felt the guys who did the grind and mag must have missed on the 'fluxing.
This was the same 312 crank found in the F350 with the heavy radiator hub and fan mounted to the front of the damper, having come from a COE Coca Cola delivery, via a '56 or '57 car. A member here warned me to make sure to look over the snout well and thorougly magnaflux. I passed that information on. Perhaps there was no crack to be found, just a worn out over fatigued crank ready to fail any minute.
It has all worked out in my favor. The weak or bad crank didnt make it into an engine. The machinist found a 10/10 that the grinder had in stock, and it is newly ground to 20/20, at his expense (it may have been a favor granted by the grinder).
Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.
