Quote:
Originally Posted by Assimilator1
Btw, AFIAK oil analysis is no use for tracking bearing wear when you have the LCI (alu/tin) bearings
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This is commonly said but likely overstated.
What you can't do with the new bearings is discern rod bearing wear from a one-off oil analysis report or a few widely-spaced ones. But that's true of basically any mechanical issue on any part with any metallurgy. The only sorta-kinda exception is that with the old rod bearings, one-off or infrequent oil analysis rate seemed to have a low false positive rate -- but it also had a fairly high false negative rate, as you know.
However, if you are doing oil analysis frequently, regularly, and consistently -- which, again, you should be doing anyway if you intend to get any use out of it -- you can watch the Al and Sn numbers and see if they rise together from baseline. You should still expect a high false negative rate, but the false positive rate should be low as these engines almost never show significant Al or Sn on oil analysis.
Also, repeating for emphasis:
we don't really know what 702/703 bearings are made of. It's almost certain that they contain Sn, and a safe bet that they contain Al and Cu. Per my correspondence with Glyco, if Al and Sn show up on oil analysis at all, it should be in a (VERY) roughly 9:1 or 10:1 ratio. Other than that, we're in the dark.