<VV> oi pressure revisited

[Mark Durham]

Mike, you never know what you will get by stretching a spring. Add
washers or buy the high press spring from Clarks. But you may not see
what you are looking for if there is a clearance issue somewhere. Do
verify the gauge, and a if that verifies lower pressure, go with a
heavier oil. Luckily the bottom ends of these engines are very
dependable. Mark Durham

Sent from my Windows Phone From: Michael Kovacs
Sent: Tuesday, September 20, 2011 1:34 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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