Bearing wear

[pfenlon]

I have removed the rear main bearing from my car to fit a new oil seal.

 

The shell and crankshaft surface are in excellent condition.

 

But a small amount of coppering is visible, but not in the usual way its seen.

 

Any ideas anyone, not a TR engine.

 

 

[Guest ntc]

edit

Edited October 17, 2017 by ntc

[john.r.davies]

Neil, as gnomic as ever.

 

Pete, there are better diagnosticians than I here, but I wonder if a bit of grit has found its way behind the shell, putting it slightly out of round.

Difficult to see how such a localised are of wear could occur otherwise (He says, bravely, as no doubt lots of ideas will be posted shortly!)

 

John

Edited October 16, 2017 by john.r.davies

[RogerH]

Hi Pete,

I don;t think that a particle of grit under the shell could distort the the shell that localised.

 

It could be possible for the under lying copper to have been built up too much in that area and thus giving a thinner top coating.

 

Perhaps the only way to find out would end up destroying the bearing.

 

Roger

[pfenlon]

Thanks for the help, I am a great believer that if its not broke don't fix it.

 

Oil pressure is sound, no noises or smoke, so I shall put everything back, with a new rear main seal of course.

 

The old seal had been fitted incorrectly, the seal should protrude upwards at one end by 3/8" ditto the other half, this seal had been fitted with the join along the centreline.

[john.r.davies]

There's a bearing here that was installed with tape on the back, that led to isolated, abnormal wear:

https://highwayandheavyparts.com/n-12632-rod-bearings-failure-analysis.html

 

John

[RogerH]

Hi John,

indeed a thin layer of tape has caused the copper to come thro' but there is significant damage surrounding the copper.

Suggesting that quite an area of the shell was displaced.

 

Pete's bearing shows no wear as extensive.

 

Roger.