<VV> oi pressure revisited

[Mark Durham]

Harry has a point. The pressures may be bit low, but that might be the
gauge. I know of 375 hp aircraft engines that can go as low as 10 psi
at hot idle with no ill affects. Mark Durham

Sent from my Windows Phone From: Harry Yarnell
Sent: Tuesday, September 20, 2011 2:51 PM
To: Michael Kovacs; VV
Subject: Re: <VV> oi pressure revisited
Stretching the spring will do nothing for the lower pressure you're seeing
when hot. The relief will be out of the circuit at that point.
Actually your pressures arn't out of line.



-----Original Message-----
From: virtualvairs-bounces at corvair.org
[mailto:virtualvairs-bounces at corvair.org] On Behalf Of Michael Kovacs
Sent: Tuesday, September 20, 2011 4:34 PM
To: VV
Subject: <VV> oi pressure revisited

Just to see the result, I added a can of old STP I had on the shelf. The
idle
pressure now at hot cruise sits at about 22-25 PSI, Cruise still starts out
cold
at 35 (factory recommendation). Hot idle is about 20 PSI. All as I expected
with
the STP in there. Next is to put mechanical gage on and compare with
electrical.
Got new standard pump and will eventually get around to pulling parts off
engine
to replace the old pump.


 What effect is there by stretching the spring?  Just curious. I think
higher
pressure as the spring acts like a pressure relief valve.

 MIKE KOVACS
............................................................................
............................................................................
........................


 1966 140 pg very well rebuilt engine by me. Balanced, bored, Steadman
heads,
mild cam etc.  Clark .010-.010 crank run out almost .000 and  plasti guaged
carefully. 10,000 miles, runs very smoothly with strong  acceleration. 20-23

MPG.

  Starts cold at 850 RPM at 35 PSI oil  pressure. After a 20 mile drive with

engine now at operating temp, Tach  at about 2900 RPM = 60-65 mph, the oil
pressure now has dropped to about  20 PSI.


 It will stay there unless the engine is idled back to 750 RPM = 13-15 PSI
and
is still running smooth and no lifter clatter.

 Using fresh NAPA 10-40 oil. Clark filter. I forget if I did the oil pump,
but
probably looked it over and reinstalled.


 I  assume the pressure relief valve is the reason for the 35 PSI cold. The
oil
press  gage is electrical and I assume it is accurate due to the steady 35
PSI
when cold even at cruising speeds. As oil heats, up just a steady  decline
in
pressure.

 Suggestions? Should I check oil pump for clearence? Change filters? Check
with
mechanical gage too?

By the way I use the same NAPA oil in all four operating Corvairs and they
hold
about 35 PSi when hot.
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