Guys,
One thing to bear in mind too is that the engine temperature is of influence
here.
When cold the pressure is much higher than when the engine is at normal
temperature.
My experience is, that an engine is at good working temperature including
the oil after running about 10 miles (or 16 kilometers for the European
continent).
Cheers,
Hans
> -----Original Message-----
> From: RJohn50603@aol.com [SMTP:RJohn50603@aol.com]
> Sent: Thursday, November 19, 1998 13:20
> To: mikesl@tartan.sapc.edu; Mgs@autox.team.net
> Subject: Re: Bouncing oil pressure - MGB
>
> Michael,
>
> An engine oil pump is a positive displacement pump which pumps its volume
> of
> oil according to engine RPM's (i. e., five times as much oil at 5,000 RPM
> than
> 1,000 RPM). A liquid (engine oil, in this case) is not compressable. This
> set
> of "givens" would be a problem if not for the very simple oil pressure
> relief
> valve which controls the pressure via a spring. The valves purpose is to
> by-
> pass excess oil that the bearings cannot use, otherwise the oil pressure
> would
> go sky high on a tight engine at higher RPM's. 500 PSI of oil pressure is
> not
> helpful to bearing life. In fact, at very high pressures the oil would
> begin
> to erode the bearing material, not lubricate it. At certain flow rates,
> oil
> viscosities, temperatures, RPM's the very simple, but effective valve can
> go
> into a cyclic motion.
>
> It does this just to perplex us and give us something to talk about. See,
> its
> working right now.
>
> An old rule of thumb is that you should have at least 10 PSI of oil
> presure
> per 1,000 RPM of engine speed. I know that takes care of my MGB situation.
> How
> about yours?
>
> R. Johnson - Dallas
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