Topic: Anyone ever seen a HAZ on a crank like this?

[cafeviking]

Huge heat affected zone on this crank. Seems weird to me, then again what do I know. I can't imagine there being a great enough temperature difference to cause this unless like... It was running at high RPMs without any freaking oil... or something? No perceptible damage anywhere else..  Except on the side of those chainrings.. or is that normal?? Nothing else is "rounded". I wonder if the primary chain is stretched out? I think this had 18k original miles when I got it, pooped at about 20, and I assume i kept her up until, say, 22-24?



Thanks in advance always guys!

[thirsty 1]

Your talking about the blueing on the crank journal correct? If so this is caused by the heat treating process from the factory and completely normal. The bearing surfaces are hardend and then ground down to the manufacturers spec. 

[cafeviking]

Your talking about the blueing on the crank journal correct? If so this is caused by the heat treating process from the factory and completely normal. The bearing surfaces are hardend and then ground down to the manufacturers spec. 

Okay. makes sense. It just seems like they'd kiln harden the whole thing to some standard that satisfied the performance of the part. I mean, era-wise you see "cheats" of this calibre. so. OKAY good to know thanks

[thirsty 1]

Here's some random reading. I like this kind of stuff so, well, I guess I could be called a lot of things lol.

http://www.sms-elotherm.com/en/products/induction-hardening/crankshaft-hardening.html

http://en.m.wikipedia.org/wiki/Crankshaft

http://m.youtube.com/watch?v=_V0xfVop1-8

I think you'll get the basic idea.

Cheers