Big end shells

[marT350T]

I have just had an engine rebuild pistons rods crack etc and when it was getting set up on the rolling road No 1 big end bearing let go. This resulted in a new crank and 1 new rod. had it fixed and within 2 hours the same thing has happened again. The car has gone back to the engine builder to get done again.

Any ideas what would cause this to happen ?

[marT350T]

Not sure if it is furthest away but I think so. Engine builder has put 2 new oil pumps in and said that everything was clean and unblocked

Also after first failure I had an oil pressure gauge fitted and all was ok before it broke

Edited by marT350T on Monday 16th June 13:53

[marT350T]

I dont think it is common on these engines I will post in the vw forum and enquired about the oil the first time and it got changed to a different grade this time.

[marT350T]

there was hardley anything left of the bearing at all and by the colour of the rod it had got really hot

[marT350T]

Yes this is what I though but with a new oil pump fitted and oil the oilways clear why would it happen twice in a row

[marT350T]

The first time it happened I think the engine must have ran for a while as I left the car with the garage and it was on the rollers.

This time it was shut off staright away after there was a plume of smoke from the crank cae breather and it started to knock.

I have been informed the all oil ways were clear and everything was assembled correctly.

[marT350T]

The engine builder did say that there evidence of detonation one one psiton. Dont know which one though.

Please could you explain why/what effect this would have on the bottom end.

Cheers

[marT350T]

stevieturbo said:

There's a difference between a detonation damaged bearing, and a fried bearing from lack of lubrication.

As he has already said, when rebuilt, they used a new crank, and rod. ( I assume this is correct ? )


You need to do a full test on the oil system, and visually check for flow.



Again though. What flywheel are you using ? Crank damper ? Ive seen cases where an ultralight flywheel has been fitted, which was supposedly balanced, and within a very short space of time, big ends failed. Twice this happened. Rebuilt again with a standard flywheel, and it was all good.

I had the fly wheel replace for a lighter one when I had my clutch replaced last year. I shall mention this point to the engine builder, Thanks.

Dont know about crank damper

[marT350T]

So just found out the No1 big end shell has gone again exactly the same as last time.

My question is now, last time it happened he said it was not under warrenty as another garage had fitted the turbo and mapped it. If the same thing happened again am I now in a position to ask for a refund for the first time this happened as now one else has touched it ?