Main bearing wear..

[Jhonno]

Would you call this acceptable bearing wear? It's the only one that seems a bit uneven, the rest are centralised and normal wear..

[steveo3002]

more details ? 100 miles or 100 thousand?

[Jhonno]

At least 20k..

[one eyed mick]

NO s*it in oil, pump is probably fubared too ! crank will need a grind !

[Boosted LS1]

Has the shell been sitting square or is there dirt behind the shell? Looks like it may be a clearance issue especially if there are signs of polishing.

If there's dirt in the oil all the shell will be grooved.

[Jhonno]

All other bearings are fine.. Just this one is like this. The crank is unmarked.

I will measure it all.

[Boosted LS1]

Is it a rear or front shell?

[Jhonno]

Actually I wonder if the other mains are normal wear now..

https://goo.gl/photos/b4YvCufa5QUvf17s9

The next main bearing.

[Jhonno]

Front shell.

[PeterBurgess]

Is the polishing on the block side of the shell too? I have seen this on five main bearing blocks when a ring gear was coming loose on the flywheel subjecting the crank to extreme vibrations. I have also seen it when someone tried to reinvent an MGB crank by knife edging it and setting up harmonics that vibrated it to death (main bearing cap cracked) and one could see similar polish marks to yours on both occasions. Maybe dual mass flywheel fault if you have one? Flywheel runout horrendous etc etc
Peter

[Jhonno]

https://goo.gl/photos/9BHu6y3n1dDbv5RJ9

Thrust bearing.

[Jhonno]

PeterBurgess said:

Is the polishing on the block side of the shell too? I have seen this on five main bearing blocks when a ring gear was coming loose on the flywheel subjecting the crank to extreme vibrations. I have also seen it when someone tried to reinvent an MGB crank by knife edging it and setting up harmonics that vibrated it to death (main bearing cap cracked) and one could see similar polish marks to yours on both occasions. Maybe dual mass flywheel fault if you have one? Flywheel runout horrendous etc etc
Peter

I will have to check the block side.. Can't remember.

I was going to Balance the bottom end anyway, so would find out if it was unbalanced..

[Boosted LS1]

PeterBurgess said:

Is the polishing on the block side of the shell too? I have seen this on five main bearing blocks when a ring gear was coming loose on the flywheel subjecting the crank to extreme vibrations. I have also seen it when someone tried to reinvent an MGB crank by knife edging it and setting up harmonics that vibrated it to death (main bearing cap cracked) and one could see similar polish marks to yours on both occasions. Maybe dual mass flywheel fault if you have one? Flywheel runout horrendous etc etc
Peter

This is what I was hinting at in my question above. Could the crank have radial play at one end?

Edited by Boosted LS1 on Saturday 11th February 00:24

[Boosted LS1]

Op, those other pics just show wear. There isn't wear on the sides of the shell because the shell hasn't been produced to be circular. The thrust faces look good from what I can see.

[anonymous-user]

Any sign of any dirt / FO trapped between block and cap face? Looks like cap was tipped sideways!

[Jhonno]

Oh yeah, I realise the sides are normal due to the reason you mention, it was the rest of the wear.

The shell in the OP was the front most main shell, the only thing rotating on that end is the air con pulley. Well, that and it drives the timing chain.

[Jhonno]

Max_Torque said:

Any sign of any dirt / FO trapped between block and cap face? Looks like cap was tipped sideways!

I will check.. I didn't inspect thoroughly, I just looked at the shells at the time.

[PeterBurgess]

The vibration can travel along the crank so doesn't always come from nearest rotating item. I bet a crank whips line one-oh if it could be filmed in slo mo.
Peter

[99hjhm]

What engine and use?

[Mignon]

Some interesting answers

First off, please post a pic of the other bearing half in that journal.

Edited by Mignon on Friday 10th February 21:32