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07-02-2015, 03:38 PM | #21 |
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Re: Understanding Crankshaft journal hardness
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.
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07-02-2015, 08:11 PM | #22 |
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Re: Understanding Crankshaft journal hardness
MikeK I'm not an engineer but I'm following what you are saying about nodular crankshafts.
Ford I know for one, used nodular crankshafts in their hi-performance engines like the 428CJ and the 427 engines in racing applications, NASCAR, Drag Racing, etc. back in the 60's. Maybe they still do today in modern NASCAR engines I'm sure they do................... |
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07-02-2015, 10:11 PM | #23 | |
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Re: Understanding Crankshaft journal hardness
Quote:
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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07-03-2015, 07:51 AM | #24 | |
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Re: Understanding Crankshaft journal hardness
Greater heat transfer? We always wanted to slow down the heat transfer by using a thick brine (salt water) to prevent cracking. Parts of the crank are pretty massive and you can have quite a difference in outer temperature as opposed to the core temperature, which induces cracking. I'm assuming that oil and air hardening steels were not available in 1928.
Terry Quote:
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