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Old 07-02-2015, 10:11 PM   #23
johnneilson
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Default Re: Understanding Crankshaft journal hardness

Quote:
Originally Posted by MikeK View Post
John, those cast aftermarket Model A cranks were cast nodular (spheroidal graphite) iron, not cast gray iron. They run extremely well at a lower hardness than a steel forging. In many ways cast nodular iron cranks are far superior to steel forgings. Nodular iron absorbs harmonics rather than ringing like a bell and is much more resistant to failure from stress-riser points than most heat-treated steel cranks. It cannot crack like cast gray iron or hardened steel, the microstructure is different. If they were available today I'd take one over a steel crank for an A.
Mike,

There was a guy making cast cranks a few years ago.
I have seen the remnants of a couple of them, you are right, they did not break. Both are bent over 1/8" on center main journal.

I am sure that done properly the nodular iron would be sufficient for a decent hotrod.

I will stick to the billet ones.

John
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