> Date:    Thu, 10 Sep 2009 06:12:21 EDT
> From:    Frank Condelli <RAlanen@AOL.COM>
> Subject: Re: Oil Pressure Sensor/Pump?
>
> In a message dated 09/09/2009 12:03:43 P.M. Eastern Daylight Time,
> LISTSERV@GERRY.VANAGON.COM writes:
>
>         Oil pressure is due to the  crank and cam bearing clearances.  Oil
> pumps produce volume not pressure  !
>

Sorry Frank, I understand what you're trying to say, but this is simply
inaccurate.  ALL of the pressure in the system is created by the oil
pump (well, ignoring thermal expansion and partial pressures).  That's
akin to say a Dam creates water pressure.  At any given RPM, it will
pump "x" volume against "y" head (i.e. backpressure), where the system
provides *resistance* to flow, and the pump produces the flow, and
therefore pressure.  So the volume of oil the pump moves through the
system is a function of RPM and resistance to flow (i.e. bearing
clearances and other frictional losses), and as bearings wear, the oil
volume actually increases significantly.  On first blush, this sounds
like a GOOD thing, but really is not at all.  The bearings rely on a
thin film of oil keeping the load bearing surfaces from contacting each
other (I know You know this Frank, but not sure the OP has such
experience) and that relies on both oil viscosity, film thickness, and
surface tension of the oil.  In the correct ranges, these oil properties
eliminate or minimize metal-to-metal contact.  When clearances become
too great, the viscosity too low, or oil volume is too high, this film
either doesn't form fully, or is too thick to maintain its cohesiveness,
and metal meets metal.  Seldom is this a friendly meeting.

So, you can "fix" this problem many times with higher volume oil pump
(i.e. one that produces sufficient volume to maintain high pressure),
but while you may keep the pressure up that way, you really haven't
addressed the primary issue, which is that the oil film in bearing
journals is still not sufficient to prevent metal-to-metal contact.
Might be somewhat better, and is unlikely to hurt the situation, but the
problem is still there.

But IMO, it's doubtful that the OP's issue with the buzzer going off
when turning corners or hitting a bump is actually oil pressure related,
unless the oil level is Really low.

Keith Hughes
'86 Westy Tiico (Marvin)