I was expecting all the engine experts to jump all over this
one, but so far I've only seen a few comments. If the gage
is relatively steady, but low, I'd suspect the gage. But,
if it starts very low and rises part way with engine speed,
it probably means pretty advanced engine wear. The oil pump
puts out flow in proportion with engine speed, but normally
this pressure builds rapidly and a relief valve keeps the
pressure from going too high. If the bearings and other
moving parts being fed by the lubrication system develop
large clearances, the pressure just can't build- it leaks
back to the crankcase about as fast as the pump can pump it.
A compression check won't necessarily show bearing wear,
because if the rings and valves are OK, the cylinders can
still show good compression.
Of course there's a lot of reasons why the oil pressure
might be low, but it's probably a good bet that a major
engine overhaul is in the cards- quicker rather than later.
Clark Searle
one, but so far I've only seen a few comments. If the gage
is relatively steady, but low, I'd suspect the gage. But,
if it starts very low and rises part way with engine speed,
it probably means pretty advanced engine wear. The oil pump
puts out flow in proportion with engine speed, but normally
this pressure builds rapidly and a relief valve keeps the
pressure from going too high. If the bearings and other
moving parts being fed by the lubrication system develop
large clearances, the pressure just can't build- it leaks
back to the crankcase about as fast as the pump can pump it.
A compression check won't necessarily show bearing wear,
because if the rings and valves are OK, the cylinders can
still show good compression.
Of course there's a lot of reasons why the oil pressure
might be low, but it's probably a good bet that a major
engine overhaul is in the cards- quicker rather than later.
Clark Searle
