<VV> Low OIl Pressure (at idle) Not Cured by More Spring

[Mark Durham]

 Pressure
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Mike, if the bearing clearances are within spec and the oil pump is in
spec, then the pressure relief bypasses whatever extra the oil system
cannot flow. It uses a simple relief spring and valve to relieve the
extra back to the pan.
However, if bearing clearances and or oil pump clearances are larger
than normal, the oil pump will not be able to keep up, hence lower
pressure.

We are having Bryan try the relief because it is simple and cheap to
do, as a test. If it helps, that's great. Bryan said he had no plans to
get into the motor so this is a good test, just in case. However, I
suspect the engine is worn out and it needs a heavy duty oil to keep
the rings sealed and the right boundary layer in the bearings with 25
to 35 psi hot. Oil is cheap. Dino oil, is better at sealing up rings
because it is less slick, comparitively to Synthetic. A good 20w-50 or
even a 15w-40 should extend this engines life for a time.
Mark Durham

Sent from my Windows Phone
From: Mikeamauro at aol.com
Sent: 8/5/2013 16:46
To: virtualvairs at corvair.org
Subject: Re: <VV> Low OIl Pressure (at idle) Not Cured by More Spring
Pressure
>From an Earlier Discussion: "...At start up I have 25 psi at idle, but it
only gets to 30 even at 3500 rpm. When warm it's hovering around 8 - 10 at
idle,  but bringing the engineup to 3500 I only get about 20 psi. I'm
thinking the easy  thing to try first is just swap out the pressure relief
spring...."

As I recall, the purpose of the relief spring is to prevent too much oil
pressure when the oil is cold and thick, and/or under higher RPMs.The
spring, I believe, begins to bypass pressure around the 30 to 35-psi
range... so,
with the pressure being low at idle 5 to10 psig, adding more spring
pressure (stretching or washers) will not boost oil pressure at idle. This is
nwhat "me thinks."

Mike Mauro





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