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Re: Steady oil pressure?

To: Tab Julius <tab@penworks.com>, mgs@autox.team.net
Subject: Re: Steady oil pressure?
From: Barney Gaylord <barneymg@ntsource.com>
Date: Sat, 15 Jan 2000 18:29:12
At 07:03 PM 1/15/00 -0500, Tab Julius wrote:
>....
>....  As far as I can tell, my oil pressure seems to be a steady 55-ish
all the time, idle or no idle.  Is this normal on a 78B, or is something
wrong? ....

[Limited education mode]
As far as I know, more than 40 psi at hot idle (after an expressway run) on
any MG would be abnormal, unless it had been "tinkered with".  Anything
over 20 psi is enough to get plenty of oil through the engine at idle, as
long as the pressure comes up quickly with engine speed.
[/Limited education mode]

[Educated opinion mode]
It might have a high volume oil pump, but that will in general just dump
all the excess oil over the relief valve creating extra heat in the oil as
it robs a little extra power to run the pump and causes a little extra wear
on the pump drive gears.  High volume oil pumps have their place in
prepared race cars, but generally with increased oil clearance in the
bearings.  You can increase force on the relief valve spring to increase
the relief pressure, but in a stock engine anything greater than about 80
psi at speed will cause excess heat in the oil, excess wear on the drive
gears, and possibly even errosion of the soft bearing surfaces in the
crankshaft bearing shells.
[/Educated opinion mode]

OTOH, 55 psi upper limit isn't going to hurt anything, so don't worry.

$.02,

Barney Gaylord
1958 MGA with an attitude
    http://www.ntsource.com/~barneymg


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