If the engine was rebuilt they may not have flushed it out
completely. If this is the case you may not be getting good circulation.
as a first step you may want to pull the oil pressure relief valve while
you are at it measure the spring it may be weak. Change your oil and
filter (this should be done after the first 500 miles) and fill it with
20w 50 weight oil.
...Art
On Mon, 8 Sep 1997, Scott Gardner wrote:
>
> > I meant to ask this during the oil pressure thread that went by some weeks
> > ago. However, better late than never. I was out for a little drive
> > yesterday (about 200 miles each way) in the '77 B and noticed that my oil
> > pressure would decline steadily until it reached about 30-35 psi at
> > 3000-3400 RPM after a couple hours of steady driving. At idle, the oil
> > pressure was about 10-12 psi. Oil pressure is typically about 65-70 at
> > cold start. The temp gauge indicated well below the midline (about 165, if
> > I remember a comment made last week correctly), which has been the normal
> > operating temp throughout the summer.
> >
> > The engine was newly-rebuilt just before I bought the car in June and
> > hasn't leaked more than a couple dozen drops of oil on my drive since. (I
> > haven't checked to see what it does when I park it away from home.) All
> > fluids levels are fine.
> >
> > The question is: Am I being unduly concerned or is the pressure too low
> > once the car is thoroughly warmed up? I am especially worried about the
> > very low idle readings, but the readings at 3K+ also concern me.
> >
>
> > Bill Singleton
> >
> > '52 TD (hers, in pieces in the garage)
> > '77 MGB (ours, we needed something fun to drive)
>
> Bill,
> I had alway used the rule of thumb of 10psi for 1000 RPM, and hadn't
> really had a problem, but after driving from Florida to Texas, I
> noticed that it couldn't up even this amount of pressure at 4000 RPM.
> Two week later, it was in the shop with several fried main bearings.
> I can't say they were related, but I'd had the car almost a year
> prior to this happening.
> What was done on the "newly-rebuilt" engine. Some sellers will call
> having some head work done "rebuilt", not out of dishonesty, but
> rather ignorance. I understand worn cam bearings can be a big source
> of lost oil pressure, and they might not have been replaced, even in
> the course of an otherwise complete rebuild, becaue they're generally
> pretty sturdy.
>
> Scott Gardner
> gardner@lwcomm.com
> www.lwcomm.com/~gardner
>
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