[Fot] Fw: Help with Oil Pressure Problem

[Joe Alexander]

Jack,

Good post.....I have been seeing this on my last two engines, but not to that
extreme.

Looking forward to seeing replies.

Joe Alexander
645 1st Street
Jesup, IA 50648
The-vintage-racer.com
Gasketinnovations.com
Cell:  319.464.4711

> On Mar 6, 2014, at 7:20 PM, Jack Wheeler <jwheeler1947 at yahoo.com> wrote:
>
> 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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