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Old 01-17-2014, 04:01 AM   #164
Jamesp
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Join Date: Mar 2013
Location: Houston
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Quote:
Originally Posted by thom4782 View Post
Jamesp:

To your last two comments...

1 - the differential effect of loading on dual and single row the rates of spallation

2 - two mechanisms at play: a) heat hardened bearing seals leak and allow engine oil to blend with / wash out bearing grease and b) contaminants build up in IMS tube oil because inflow and outflow rates are different and they find their way eventually into the IMSB through the leaking inner bearing seal
Thing 1- Once spall begins in any bearing the rate is not of consequence - spall is the removal of chunks of material, not normal wear. This is a failure mode that feeds on itself and quickly destroys any bearing. Lack of lubrication or overload can both result in spall. I posted a picture of cut bearing apart bearing that had lines in it that looked like it could be the start of spall. Jake commented that bearing was failing, but no tribologist came forward to name the failure mechanism.

Thing 2 - You're on the right track, but there needs to be a motivating force to push oil into the bearing or it would tend to just drip off the bearing seal. Granted it would tend to soak in under its own power, but I wonder what motive force could literally push oil past the seal to fill the IMS tube with oil? It may have something to do with thermodynamics.
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