Hi Dave,
Is the oil fresh? Is there any possibility that it has been diluted
by coolant leakage, not that that would happen w/o the telltale creamy
appearance on dipstick and filler cap. It's 20/50, not 5/30? Any
crud/sludge in the oil filter? Engine temp normal? I would look at
the big-end bearings right away.
Once upon a time I saw an MGA drag its rear wheels on an interstate
when the owner-driver neglected an oil pressure gauge that was dropping
from 40-30-20-10-0 within just a few minutes ( possibly five or fewer; it
was just one exit on the CT turnpike ). The crankshaft was OK on three
journals, but all chewed on the fourth. One suspects that the last four
minutes of operation cost him large $$ per minute.
We removed the engine to work on it, so I can't comment on the effort
required to change bearings in the car, but doing it in the MGB is easy,
and both are B-series engines. John Twist has written that the main
bearings in MGB engines last 3x or more the life of big-ends, so the
mains are probably OK unless you know that they have a zillion miles on
them.
Bob
On Sat, 21 Oct 2006 22:15:44 -0400 dave houser <mgs4dave@tampabay.rr.com>
writes:
> Listers,
> Last few times I had my 1960 MGA coupe out, I noticed the oil
> pressure dropping somewhat.
> Today, after a morning drive, I noticed the pressure at 40, idling
> at around 10. Coming home the pressure dropped to 35 hot and was
> heading to zero once I shut things off.
> Temps in Fl around 85, not too bad.
> Am I looking at big end bearings?
> TIA,
> Dave Houser
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