Discoloration on crankshaft

[anthracitedub]

Getting ready to build another 40 horse. I have this crank that looks like it may have gotten hot, but the journals look half decent... would clean up with a 10.

I'm not too sure about the condition of the crank though. It is standard throughout, but the signs of heat raise concern.

Should I pass on getting this crank polished/ground?

[modok]

no, that's not a bad sign, that's how they all looked new.
Induction hardened, gives rainbow colors around all the journals.
Once you hot tank it a few times, wire brush it, shot peen, ect, the evidence will disappear.

[anthracitedub]

Cool, I was hoping that it was part of a hardening process... it did seem kinda uniform over the journals.

[mark tucker]

polishit a little and see how the size is, I wont turn one till it needs it, many morons turn cranks just because there...morons and dont know any better. the hardening is only so deep, not the entire thickness, cut it and....soft and..soft wears fast.

[anthracitedub]

I'll clean it up and mic it, hopefully just a polish.