On Thu, 26 Oct 1995, Russ Wilson wrote:
> This point is forever being repeated but is contrary to my observations:
>
> >Over a night or a few days, there is still a thin layer of oil on the
> >bearings,
> >but when you're talking months, there will be very little oil left.
>
> >Dave Williamson (silikal@aol.com)
>
>
> The problem I have with such statements is that I have never seen an engine
> with dry bearings. I recently disassembled a TC engine that had not been
> run for 9 YEARS. The water pump had time to corrode into one soild mass
> but the bearings were swimming in oil, as if the engine had just been run.
> It's not a question of waiting long enough - a liquid just can't run out of
> a thin gap. Surface tension would, in fact, draw oil *into* an initially
> dry bearing.
> What gives? Is this one of those myths that lives long enough to become
> "fact" or am I missing something? What does our oil expert say on this?
Perhaps it isn't the drainage from the bearings so much as the drainage in
general. I have had a few cars over the years that had a bit of bearing
rattle until the oil pressure built up--one was a Toyota that did this
from new (and probably is still doing it at 180,000 miles). There seemed
to be a correlation between how long the cars sat without running and the
length of time needed for the bearings to quiet down. Re the capillarity
argument, capillarity might draw oil into the gap if the gap were
immersed in oil, but that's not the case.
Ray Gibbons Dept. of Molecular Physiology & Biophysics
Univ. of Vermont College of Medicine, Burlington, VT
gibbons@northpole.med.uvm.edu (802) 656-8910
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