3516 CAT engine crankshaft journal

[Yasser emam]

This is the center main bearing journal of a CAT 3516 engine crankshaft and as you can see there are these colour stripes but by inspection with hand i can't feel any bitting or roughness.
This journal doesn't have oil hole
Anybody have seen this before?
What is the cause of it?
Is it normal, abnormal or critical condition?

 

[catserveng]

Hard to tell for sure from the two pictures, but most likely cause is discharge pitting. The "frosted" apprearence is typical of that kind of problem, the striping may be due to the source being AC. Is this the only journal showing this kind of wear?

Because this journal doesn't have an oil hole the pitting on the bearing seems abnormal. Some cavitation erosion is typical on most of the mains but not usually the center main. Closer inspection of both the crank and bore side of the bearing are needed. look for small blackened areas or pits on the shell side of the bearing.

Need more details on the engine and its driven equipment to make a better answer.

What is the engine application?

How many hours?

You may have get some better answers at the CAT forum,

https://forums.cat.com/s/

 

[TugboatEng]

If it is electrical in nature I would guess that the appearance of the lines is due to it occuring when the engine is stopped and the oil film very thin. Engines sometimes favor certain positions as they stop so that may explain the formation of distinct lines.

 

[enginesrus]

I have a few ideas. Since the appearance is similar to chatter marks, there could have been chatter introduced during the grinding, and was polished before assembly or during normal manufacture or repair. The other idea is vibrations and excessive bearing clearance. No it is not normal. So can you give us more information, like what the crankshaft reground, and how far under size? My first impression was breaking through case hardening but I'm sure it wouldn't look like chatter.