[Fot] Fw: Help with Oil Pressure Problem

[barry rosenberg]

I have been building these engines since 1975 and have found most of these
problems are from the pump. A good machine shop would not send a crank out
with too much clearance so I doubt that. If you are certain the filter head
was clean then I would pull the pump out and check the end clearance. This is
more critical than clearance between the rotors. I always chuck my pumps, new
or used, in my lathe and and machine the rotors and housing flush. Then I take
about .001" off the rotors. Clean very good and reassemble. I always use
petroleum jelly on all my rebuilds as it dissipates in the hot oil completely
and an engine can sit for years and still be primed, coated and ready for
use. 

Barry Rosenberg


________________________________
 From: EDWARD
BARNARD <edwardbarnard at prodigy.net>
To: Jack Wheeler <jwheeler1947 at yahoo.com>;
"fot at autox.team.net" <fot at autox.team.net> 
Sent: Thursday, March 6, 2014 10:38
PM
Subject: Re: [Fot] Fw: Help with Oil Pressure Problem
 

Jack:
Last year we
had this problem on a new build for Bob Blake's "4" motor.
It really had us
scratching our heads until Bob pulled the pressure relief
spring and ball and
found that the thick assembly lube I used had traveled
with the oil and
clogged the ball and spring and caused it to seal
erratically. I replaced the
spring and ball at the track with one from another
filter head and that solved
the problem. I have not used the white assembly
lube on another engine. 
Easy
place to start.
-Ed Barnard-
________________________________
From: Jack
Wheeler <jwheeler1947 at yahoo.com>
To: "fot at autox.team.net" <fot at autox.team.net>
Sent: Thursday, March 6, 2014
7:20 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
_______________________________________________
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/edwardbarnard@prodigy.net
_______________________________________________
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/britcars@bellsouth.net