<VV> Replacing Oil Pressure Regulator Spring

[Mark Durham]

Frank and all. The spring and plunger should not be regulating anything
at idle. It is a pressure regulater, but at the other end, the top end.
So, if you are getting 45 psi at higher rpm's, the spring stays closed
to that pressure, then opens enough to return excess pressure. Pressure
at lower rpm's is the pressure developed by the pump versus all the
places oil flows through. If the pumps flow matches flow, there is no
pressure. If flow capability is greater than the places oil needs to
flow, you get pressure, up to the relief spring setting. that why at
idle, pressure is normally lower. The pumps volumetric capacity at idle
is not much greater than where it flows, at higher rpms the volumetric
capacity to pump goes up, and so does the pressure.

Yes, too much pressure can be bad too. One time I solved a engine dying
problem when the engine got above 2500 rpms. The oil pressure relief
valve had stuck shut, and every time the oil pressure climbed above 60
psi all the lifters would over pump, open the valves, and kill the
compression. So you would pull to the side of the road, by the time you
would stop, it would bleed down and start right up again. Mark Durham

Sent from my Windows Phone
From: Frank DuVal
Sent: 3/23/2012 14:18
To: virtualvairs at corvair.org
Subject: Re: <VV> Replacing Oil Pressure Regulator Spring
I'll take a stab at the explanation. Spring below includes the operation
of the plunger in the description. The spring alone cannot  dump
excessive oil pressure, the plunger does by exposing other passages in
that rear cover.

The spring regulates oil pressure, by bypassing excess oil back to the
sump if the pressure is too high.

Oil pressure will be greater when the engine is running higher revs.

At idle, the available oil pumped through the passages of the regulator
is less than at higher revs.

Since the spring regulates to some pressure that keeps the light off at
revs above idle, and there is less oil at idle,  the spring is not
regulating the pressure below the light turn on setting at idle. There
is simply not enough oil supplied by the pump to turn the light off. The
regulation setting is determined by the spring, but that setting does
not change with pressure of the oil. But when the oil pressure is below
the setting of the spring, the spring cannot "pump" the oil pressure to
a higher level. The spring can only lower oil pressure.

So if the spring was weak and bypassing oil pressure at a low setting,
that should also happen at speed, not just at idle.

Flame suit on awaiting people who can write better to respond!

Frank DuVal

On 3/23/2012 1:03 PM, Joel McGregor wrote:
> Hate to disagree but it could possibly be the spring.  I've had it happen with the exact symptoms he has.  Springs do settle especially after so many years and so many heat cycles.  Mine happened 20 years ago.  His light is coming on but how would the light being on or off tell you that it could or couldn't be the spring?
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