[Farmall] oil pressure

[olmstead at ridgenet.net]

Bob, I don't have any info on which gauge reads what, but I got tired of
dealing with it a year or so ago and installed nice, glycerine-filled
gauges on my F-20s.  They run 25-30 psig right after being started, and as
low as 5-10 psig at idle once the oil is hot.

(I'm an instrumentation weenie; PSIG means PSI above atmospheric.  In
other words, the gauge measures pressure relative to atmospheric pressure,
so zero psig is around 14.7 psi above a vacuum.)

Other than maybe the camshaft bearings, I don't think there are any
pressure lubricated bearings in an F-20.  There's no oil provided to the
head at all, and the rod bearings are splash lubricated using oil sprayed
by tubes along the side of the crankcase into troughs under each rod cap. 
I don't remember if there is any special provision for oiling the big ball
bearings that support the crankshaft, but if there is, it is either spray
or splash.  In other words, virtually any pressure at all is enough to
keep the engine happy.

The F-12 is a different animal; it follows modern oiling conventions.  I
generally see 25-45 psig cold, 12-20 psig hot.

I can calibrate pressure gauges if you send 'em to me.  It would take just
a few minutes per gauge.  Anyone can do it... all it takes is a simple
manifold equipped with a decent, calibrated pressure gauge, a quick
connect for your air hose, and a couple of needle valves.. one for letting
pressure in, another to vent it.

To head off complaints, tractor manufacturers made the gauges pretty
optimistic.  I've read that some Caterpillar oil pressure gauges indicate
'OK' when they sense 2 psig.

-Karl
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> Most of the unstyled IH products ran on pretty low oil pressure from what
> I have gathered. In trying to determine what is "good oil pressure" for a
> 10-20, 15-30, Farmall Regular or F-20/F-30, I'm getting all different
> kinds of information. So I figure the best way to determine the good or
> bad pressure is with the correct oil pressure gauge for my particular
> tractor(s). What I've found is pretty confusing. Two different part
> numbers for the 10-20, 15-30 gauge show using either a 4# gauge, or a 10#
> gauge. I see a very nice original gauge for a Regular/F-20 on Ebay right
> now and the seller says it tested for a 25# gauge. I talked to a couple of
> gauge remanufacturing people in our hobby and they say a #15 oil pressure
> gauge would be correct. So my question for you folks is where would you go
> to find the correct pressure listings and applications for the various
> tractors,, and how do you test a gauge to know what pressure reading it is
> showing? These old gauges don't have any mea!
>  ningful numbers on them to use as a reference. So if the dial comes
> halfway up and it pointing straight up and down, is that 5lbs, 7.5lbs, or
> maybe 12.5lbs.?
>
> bobcurrie