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Bearing Wear

Posted: February 25th, 2009, 11:36 am
by Bodo
Howdy Gang

I've got a problem that I hope ya'll can help me with.

We tore down a motor that showed some very strange bearing wear.
540 ci BBC 700HP with 4 hours run time ,13qt oil pan typically run at 6000-6800 rpm in a 10,000lbs 'bog truck'.

Looks like cavitation. Any input or experience that you may have would be welcome.

The mains look great, the rods are toast. :shock:

Re: Bearing Wear

Posted: February 27th, 2009, 8:51 pm
by 5-90
That almost looks pounded out. What was your oil pressure like? The rods are fed from the mains, which is why the rods would go first...

Re: Bearing Wear

Posted: February 28th, 2009, 6:49 am
by Bodo
Thanks for the reply.

Oil Pressure was always around 60psi, according to the owner.

I need to take some better pictures, but the surface is fine on the rod bearings (except for the odd material removal cut that you can see). The other wearing that you see if from the material removed banging around.
Brand new King bearings too.

Re: Bearing Wear

Posted: March 1st, 2009, 12:45 am
by 5-90
Hm. Were those worn bits in line with the oiling holes in the crankpins? Just curious... And, in what condition were those oiling holes, anyhow? I have seen some cases where there were slight burrs in the oiling holes after grinding (I will almost invariably chamfer them myself...) that could also cause some gouging like that.

Re: Bearing Wear

Posted: March 1st, 2009, 4:46 am
by Bodo
Yup, they match up very well with the oiling holes. When I get to the shop today, I'll inspect them a little closer. Thanks!