Blue crankshaft, yowzers

[Casa de Mesa]

So um.... is this normal?




Thought it might be a hardened crankshaft but googling shows up little.

I found this, which is a super weird coloring, but turned out to be part of the hardening process:

https://www.m3post.com/forums/showthread.php?t=1530957

But this is weird.

-Casa

Edit here is another photo:

[cobra]

Yeah that's very blue!

I am not sure what bad thing could have caused it though, so I'm sure it's fine?

[maupineda]

Maybe heat?

[Slideways]

HPF had a video that showed an engine being assembled and in that video, the counterweights on the crankshaft were blue. They said it was from the hardening process/treatment from factory (nitriding?).

[SteelGreyM]

Hey. You are correct in that the crank counter weights are blue. That however should not be blue. What tht looks like to me is the same color as the pilot bearing. Something was rubbing and the material transferred it seems.

Kind of a shot in the dark but maybe 🤷🏻♂️

[jbfrancis3]

From what I've read the blue is from a tempering process. A science paper (albeit not a very good one) tested a BMW crankshaft (without naming it) against a crank in a diesel application. The diesel one was hardened whereas the blue BMW crank was found to not have hardening layer. Source at bottom, go to pg 4.

Tempering at temperates between 500 and 600 deg will result in blue/purple appearance. What specific properties are sought by BMW by tempering, I'm not sure.

Obviously, it was during manufacturing where this super blue one was formed. Nothing to worry about (more accurately: nothing to be done about it).

https://pdf.sciencedirectassets.com/314029/1-s2.0-S2452321616X00029/1-s2.0-S2452321616000433/main.pdf?X-Amz-Security-Token=IQoJb3JpZ2luX2VjEFgaCXVzLWVhc3QtMSJHMEUCIF2rdwFHMA62NNy61xAiOmk%2Bwo2qGbFMV0Wk2BaK4iHsAiEAw2wL5oNBjMPN%2FcRpLcOkEKjwBrqKXjaZwx977orpUTsqgwQIgP%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FARAEGgwwNTkwMDM1NDY4NjUiDO4JB0Nba7bAL2VqBCrXAxJeWrd5C04lxxXcMYiZXlz2wpH2NBHgVZGLIUbFW4tNIsWyE%2FBA024nfW0jJRRCsAV7GPm0YNLcy5yDaNEvT91L93P1y4b3xGMSdX9kWGiyPxU6sVyFS0wmXToKwP%2FktI111S3yeRd38niUMA7hwDCBJmLBb%2Bu6Xqnn2b5Kw5HpgSTVNKoua3wepkvtMW%2B4Zudhzxg8Wgtt3almNB10iHkDYOCZQIkxPFU0biGyWCjCRw1R4aEspFZJg7QIAc5bz2dyc6xedhsL8QnSHYAcgNBlnhDBxpa8gr97s01iEGsaxyO4Jmod9XDwemDBVPdHvuIsHKLXavV5HZ8tg7DigF%2FKPDPGDgjDI9Mg6lH5Pxhj7HGvd4xjh8zmCPRTUSQLYIfhHiP7h627BTiF6bs7t1S1l4sPAWR6yoHuIxL39xeGm5nWQsOx1x0Y1c8MV3f%2BFh5MWZGzySxMeL7DlhFdWUzTgEHN62hVMzzVlmdYTgbH7lPmvMXeVawsI1UTrqSBQuxtPb%2BGND4Yj%2FvIGo2j9enZVZ2yIJ5MD2eh%2BqoGzA1QLX2L2UTQT0mfTbfaKRnfA9RX9L1lsc5d4BcCYYCYGvzOU8VKuFUMfzAh218xvlSwb9mxGy4E%2BzDb5LyPBjqlASO%2FxJTWS9FcKy1o4SMDDwg0y3I0pJTqi%2FVPa81W8BKifydoZ%2BjnJujCDUZtYS6JJRIyKLPMbGTHPtah6mU9cDyDmayzCmo%2F%2BIDc2v6m7Y13esUmCBwecvEk%2B00YEuHHiMYMxENX93zAas99bsO1nKgjf7w6nxw4cDHkzXHmg%2FEgP00HYOO9lavKUcKLMYq6SySvaPzWLwbm6xGTttnody9SwwCq8g%3D%3D&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20220125T005514Z&X-Amz-SignedHeaders=host&X-Amz-Expires=300&X-Amz-Credential=ASIAQ3PHCVTYZAIYSDOA%2F20220125%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Signature=bfdceaadd20275b657411ff74c6be79cb0b1282213e1b0b3a729ee3a0362f90a&hash=2e9eaf96ea531fd358236f0823e37d9f8f724034d4e7886d234452ba6e486bd7&host=68042c943591013ac2b2430a89b270f6af2c76d8dfd086a07176afe7c76c2c61&pii=S2452321616000433&tid=spdf-699f9625-223c-45da-a223-21a9bba51b97&sid=47ae4f2c537e0744a2799db0684e5bdfa34dgxrqa&type=client

[Casa de Mesa]

Thanks for the replies guys.

I assumed it was a hardening process of some sorts via temp, but had never seen that on any S54 crank photos or first hand. I'm sure there are manufacturing tolerances/differences from one part to the next, but I would have thought a crank is a fairly complex part and the disparities between crankshafts would be minimal. So it surprised be - thought I would have seen this by now.

Camera doesn't really pick it up (and it's still a bit dirty from disassembly) but that thing is a beautiful blue. I'll getter better pics as I continue the tear down. Makes me wonder if the entire crank is that color (likely not, but that would kick ass).

jbfrancis3 that link is awesome, thank you.

[heinzboehmer]

Camera doesn't really pick it up (and it's still a bit dirty from disassembly) but that thing is a beautiful blue

You should paint your car "heat treated crank" blue

I remember my crank being pretty blue when doing rod bearings. Not like yours, but yeah.

[Casa de Mesa]

You should paint your car "heat treated crank" blue

Lol! Crank MF Blue!!

I remember my crank being pretty blue when doing rod bearings. Not like yours, but yeah.

Really good to know.

I figured for it to be that blue, it had to happen before it was put in the car. That rear main seal is in pretty good shape and would otherwise be nothing but goo if the crank got blue while on the car!

[jet_dogg]

Means your engine got blue balls my boy.

[bigjae46]

The S54 crank is hardened. If you ever have the journals ground, the crank should be re-heat treated. Lang's S54 repaired crank at $800 the last time checked is an excellent deal.

I don't remember ever seeing a crank being THAT blue.

[DoubleSidedTape]

I recently did bearings as well as replaced a flywheel. Crank was definitely green on the counterweights but not especially colorful where the flywheel bolts on.

[Icecream]

Hey. You are correct in that the crank counter weights are blue. That however should not be blue. What tht looks like to me is the same color as the pilot bearing. Something was rubbing and the material transferred it seems.

Kind of a shot in the dark but maybe 🤷🏻♂️

That is what it looks like, doesn't look like its "in" the metal from the pics at least and the center has some bits too.

[SteelGreyM]

That is what it looks like, doesn't look like its "in" the metal from the pics at least and the center has some bits too.

Look at his pilot bearing. It’s all worn out. How it got around onto the crank there I do not know lol.

[digger]

Looks like blue dykem, or maybe someone got too generous with the blue loctite lol. Doesn't seem like anything to worry about in anycase