REwald9535@aol.com wrote:
>
> Michael,
> The oil pressure relief valve is to prevent too much pressure in the engine
> when it is new and clearances are tight.
The oil pressure relief valve is used for the
life of the engine, not just when new.
If you can imagine, the oil pump runs off a fixed
linkage to the engine guts, so it spins at a rate
that is linear with engine speed.
In order to provide enough pressure at idle, the
pump has to be geared so it can make enough volume
and pressure at a 500 rpm idle speed.
Needless to say, that becomes a LOT of volume
and pressure at redline, which is over 10x idle
speed.
The relief valve provides the mechanism to vent
all the extra oil safely back into the sump. By
changing the spring pressure, you can adjust the
maximum oil pressure your engine will have.
You see this all the time in a normal engine,
the oil pressure will not rise above some point
on the gauge, usually around 75 or 80psi.
If your engine has varying oil pressure that
is SOMETIMES good enough but too low at idle, then
a new valve won't help you.
If your engine doesn't have enough pressure even
at speed, and you never seem to be able to get it
high enough, it might be something to look into. The
valve might be jammed open causing a short circuit.
(or special case for Tyson, if you get 100psi
of pressure at idle, the darn thing is jammed
shut again)
--
Trevor Boicey, P. Eng.
Ottawa, Canada, tboicey@brit.ca
ICQ #17432933 http://www.brit.ca/~tboicey/
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