oil pumps (not efi)

[William A. Sarkozy]

At 07:20 AM 12/11/96 -0600, you wrote:
>Not an efi question (If you are under 18 or are offended by
>non-efi related subjects please leave now :-)
>
blah blah

Tom,

As you probably know, oil pumps are essentially gear pumps which are of the
POSITIVE DISPLACEMENT  type.  Simply put, they want to pump a specific
amount of oil for each revolution of the pump.  Obviously, there's some
leakage and ineffeciencies involved, which leads to a finite (if however
high) pressure if they are dead-headed.  A "high volume" pump typically is
identical to a standard pump with the exception of the transverse gear
dimension is a bit longer, meaning that a bit more oil is pumped for each
revolution.  All else constant, this increased volume per unit time will
result in an increased pressure.  The reason people prefer high volume pumps
is that they tend to hold up system pressure when all the other variables
(heat, viscosity, and increased clearances) tend to lower system pressure.
And don't worry about the froth.....get a good windage tray, a high capacity
pan, and baffle the pick-up propery....that's all that's needed.  And
remember the rule of thumb for oil pressure....10 psi for each 1000 RPM.  If
you find you're making too much pressure when the engine is cold, you can
put an external pressure regulator/bypass  at the closest access point to
the pump.  BTW, I always run a high volume (Big Block) pump on my small
blocks without a hardened shaft and work up about 90 PSI at start, dropping
to about 50-60 between 1500-5500 RPM...I use turbos so I never have to take
the motors way upstairs to make power.....never had a problem yet.

                                                                            
     good luck

                                                                            
         Bill