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Posted by: tscrihfield Jun 2 2011, 09:00 PM

So I have a concern. During the inspection of a crank I recently obtained I found discoloration (much like gun blue) on the area outside of the middle main journal. I'm not as versatile in air-cooled engines and im not sure if this is normal??? All of the journals mic'd fine and well within spec. This is not a good sign when dealing with most engines I know, but I am wondering if this is normal. Would this be a replace scenario?

Posted by: tscrihfield Jun 2 2011, 09:02 PM

To clarify it is in the thrust bearing area, not on the actual journal itself.

Posted by: r_towle Jun 2 2011, 09:05 PM

Not sure where you are talking about.
Is this a used crank?
You may want to get it polished.

Rich

Posted by: Jake Raby Jun 2 2011, 09:05 PM

Totally normal if its what I believe that it is.. I have seen NOS cranks for TIV engines have this discoloration.
post some pics.

Posted by: tscrihfield Jun 3 2011, 08:02 AM

Will post pictures when I get home. This is a stock 2 liter crank and it is used, but the journals are in terrific shape.

Posted by: tscrihfield Jun 3 2011, 03:32 PM

This is the area of discoloration... Let me know what you think. I will have it polished anyway but this is my only area of concern.

Posted by: Don M Jun 4 2011, 07:18 AM

appears to be trace discoloration from factory induction hardening process, as long as size, finish and run-out are acceptable not a problem

Posted by: tscrihfield Jun 4 2011, 08:39 AM

Thanks! Glad to hear that! I thought it might have been from heat treating but wasn't so sure!