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Re: Oil Pressure Questions...

To: mgs@autox.team.net
Subject: Re: Oil Pressure Questions...
From: "John M. Trindle" <jtrindle@tsquare.com>
Date: Tue, 11 Jul 1995 11:34:15 -0400 (EDT)
On Sun, 9 Jul 1995, Jon N Swanson wrote:

> What is "normal" oil pressure for a '73 MGB and what steps can be taken
> to improve it short of a complete engine rebuild (or are there any worthwhile
> steps...)  If somebody wants to point me to a resource on the net I'll be 
> happy to do the looking up myself.
> 
> I have a '73 with approx 120k miles on it.  Unknown history of any engine
> rebuilds.  I currently have 10W40 oil in it.  When I start it cold it keeps
> the oil pressure up around 60psi constantly.  After it warms up, it holds
> 50psi for 3000RPM+, 40psi for 2000RPM, and drops to 15psi (gulp!) or so
> (tough to read the guage that low...) when idling around 1000RPM.
>
This is normal.  The oil pressure relief valve should limit your reading 
to 70 psi when cold.

I have about 5000 miles on a rebuild and am getting your readings with 
5W50 Castrol Syntec.  The only reason mine might be a little low is that 
I did not put in oversize thrust washers in the rebuild.

The rule of thumb is 10 psi for every 1000 rpm.

I'd consider going to a 20W50 conventional or 15W50 (Mobil 1) or 5W50 
(Castrol Syntec) oil.

If you are getting oil splashed on the rockers at idle your pressure is 
probably OK...  If you notice a >change< in the oil pressure at cruise 
(starts dropping from 50 psi down toward 35 psi) then you are at the end 
of bearing life and/or have contaminated (or missing! <sick grin>) oil.
 
> Another question I just thought of - I have a jack for my MG but I'm not
> sure it is the correct one.  It says Bilstein on the top and has a round
> bar that protrudes about 7".  This bar seems to fit into the jacking point
> on the car, but when I try to raise the car, the top of the jack tries to 
> embed itself in the door.  Am I missing part of the jack or do I have the
> wrong one?  Is there supposed to be some sort of extension bar?
> 

This sounds like my jack.  I have to jack it up until the base is lightly 
resting on the ground and adjust the base so the top of the jack is about 
1/8" from the door.  If you just jack it willy-tilly the top will impact 
the door. 

I use a hydraulic floor jack now, since I am concerned about stripping 
the worm and pinion gears in the stock jack.  I have to be VERY careful 
about where I place the floor jack, since I don't want to crush the stock 
jacking points or the "box beam" (whatever you call that transverse 
reinforcing box).
 
John M. Trindle | jtrindle@tsquare.com | Tidewater Sports Car Club
'73 MGB DSP     | '69 Spitfire E Stock | '88 RX-7 C Stock
Home Page:  http://www.widomaker.com/~trindle
"Any given container designed to hold water, will leak, and any given
orifice designed to drain water, will plug up. - Walter Aiello"


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