[Fot] Fw: Help with Oil Pressure Problem

[Dean Tetterton]

  Jack
          The last engine I built showed this problem. After about a 30 minute
drive
and the engine got up to temperature, the oil pressure would be at 10
lbs at idle and 60 at 3000 RPM. I had replaced the pressure relief valve
spring and ball. I put the old spring back in and so far the problem
has not reappeared. I think the new spring is either losing tension
when hot or is hanging up in the housing.
           Did you put in a new spring?

Dean T.


On Mar 6, 2014, at 8:20 PM, Jack Wheeler 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
> _______________________________________________
> fot at autox.team.net
>
> http://www.fot-racing.com
>
> Donate: http://www.team.net/donate.html
> Archive: http://www.team.net/archive
> Forums: http://www.team.net/forums
> Unsubscribe/Manage:
http://autox.team.net/mailman/options/fot/tr3a58@verizon.net