<VV> Replacing Oil Pressure Regulator Spring

[Joel McGregor]

An old spring could still be stiff enough to have the correct pressure when the volume is higher but not long enough anymore to keep the valve completely closed.  It would allow enough oil to bypass to make the light come on at low rpm but not enough to keep the oil pressure low at a higher rpm.
If the spring was just too soft and therefore working properly but regulating the oil pressure at too low a setting then you would be correct.
I figured the first scenario was what happened to mine since stretching the spring a bit fixed it.

-----Original Message-----
From: virtualvairs-bounces at corvair.org [mailto:virtualvairs-bounces at corvair.org] On Behalf Of Frank DuVal
Sent: Friday, March 23, 2012 4:18 PM
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