Apparently the radius on  a crank is often lost or worsened by incompetant regrinding..


Paul

Thanks for your reply David. A couple of things I have learned during my search for a crank and talking to knowledgable y block people.  1. The crank MUST be crack tested as cracks are common due to the very small radius on the journals, and 2, if the crank has been stored on its side ( particularly for 40 years), then is most likely has a sag or a slight bend. Cranks should always be stored on their end or bolted into the block.  Crack testing of my crank cost me NZ$100 and thank goodness I did it.
If you or anyone has a good 312 crank and show me a certificate to say it has been crack tested, then I am interested.
Many thanks
Mal

Charlie's right. I bought a running 312, but smoking, compression low, needed a rebuild. But no lower end noise. The crank didn't pass the mag check. Still ok in a worn motor, but it wasn't going to live as a 340 stroker with 8lbs boost.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Quite the opposite.  It's too expensive not to check for cracks.



Lawrenceville, GA

I've had a 312 crank sitting around for 40 years. Just today I decided to have the journals mik'd to see what shape it's in. Probably would be too expensive to have it checked for cracks. Anyway, if nothing else turns up maybe we can figure something out. I'm located in the San Francisco Bay Area.  

Hi All, before starting the rebuild of our 312 from our 1957 T-bird, we had the block and crankshaft crack tested and the crank has a 1 inch crack on #1 journal.  Anyone have or know of a good 312 crankshaft for sale? It would need to be crack tested before I buy and ship all the way to New Zealand.  Any help appreciated. Cheers Mal.