[Fot] Fw: Help with Oil Pressure Problem

[Greg Solow]

Jack, This sounds like excessive clearance in the oil pump to me. Although 
when I bought my first Morgan, new in 1965, the oil pressure would drop to 
20 psi on the guage at idle when the oil was hot, but would jump up to 70 
psi by the time the engine was at 2,000 rpm.
This was using 20w-40 motor oil.
                                                                             
                               Greg Solow
----- Original Message ----- 
From: "Jack Wheeler" <jwheeler1947 at yahoo.com>
To: <fot at autox.team.net>
Sent: Thursday, March 06, 2014 5:20 PM
Subject: [Fot] Fw: Help with Oil Pressure Problem


> I've never sent a message to the FOT group before, so I hope I am doing
> this correctly.
>
> I just finished rebuilding the engine in my TR-3, and it is
> showing some unusual and disconcerting information on the oil pressure 
> gauge.
> When cold, the pressure ranges from 60 psi at idle up to 80 psi at 3,000 
> plus
> rpm.  However, last weekend, I took it out for a drive and after about 25
> miles, when the oil was up to full temperature, the pressure dropped to 
> almost
> zero psi at idle, but still kept showing almost 80 psi at 3,000+ rpm.
>
> I have
> built these engines for over 40 years and have never had this problem 
> before.
> The first thing I would think of is bearing clearance, and for years I 
> always
> checked the bearing clearances with plasti-gauge when I assembled one. 
> When I
> was racing, I had a crank grinder who was so good, I gradually stopped 
> doing
> the plasti-gauge check (I never found one that was out of tolerance).  In 
> this
> case, the crank was standard size and the crank grinder recommended that 
> he
> polish it, which he did.  Although this guy is new to me, he was 
> recommended
> by someone who rebuilds race engines for a living, so I trusted him.  I 
> guess
> he could have polished too much off the bearing surfaces, although I would
> have thought he would have checked that after he polished it (I certainly
> should have - and will next time).  The other thing that could cause too 
> much
> bearing clearance would be bad bearings.  Has anyone seen problems with 
> main
> or rod bearings, resulting in excessive clearance?
>
> The only other thing I
> could think of is a failure of the pressure relief springs in the oil 
> filter
> head.  The long spring, which is used to adjust the pressure is still
> available, and I
> always replace them when I rebuild an engine as standard
> practice.  The shorter spring, which is there as a fail save to keep the
> engine from starving for oil if the filter gets clogged up, is not 
> available,
> and I have never replaced one.  I did not use this spring in my race car, 
> as I
> had a custom made filter head which excluded this oil pathway, but I have
> never had a problem, that I know of, with this spring in street car 
> engines.
> Has anyone seen symptoms like this before, with a newly rebuilt engine, or
> have any suggestions what might be causing this?  Thanks for any 
> ideas/help
> you can give me.
>
> Jack Wheeler
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