Oil Pressure

[George Arber]

I need some collective wisdom and hopefully just a little reassurance
please .

I am moving well ahead now with my restoration of our TC EXU with the main
wiring completed and this evening managed to fire up the engine. The
restoration has been a long term adventure and I fully rebuilt the engine
some six years ago, including new camshaft, crank regrind, , new shells and
a rebore etc., - maybe I should have left the engine ' till the last, but
having had to rebuild it in the first place as a result of number one piston
going pop, it was only after the rebuild that I decided to get the rest of
the car back up to scratch.

The rebuilt engine has been stationary in the chassis for around six years
and I had given it an occasional turn with the starting handle after putting
a teaspoon of oil in each bore via the spark plug holes. Prior to firing her
up, I primed the oil pump and whizzed the engine over on the starter with
the plugs removed and after a short while the oil pressure gauge registered
20 psi. What is giving me cause for concern however is that after firing up
the engine, the gauge only registered 20 psi and gradually crept up to just
under 40 psi on a fast tickover of approx., 2000rpm It seemed to take ages
over a minute ) to creep up to this. Blipping the engine a little higher
made no difference .

During the engine rebuild I lapped the oil pump end plate to adjust the end
clearance of the gears and replaced its bushes. I recall that I did have
difficulty in removing one of the shafts. Another point is that the oil in
the engine was fresh and clean, but that was six years ago ! I cannot see
however that new oil would make any difference regarding the oil pressure.

Maybe I am just a little too anxious at this early stage, but my
satisfaction on hearing the music after such a long time has been tempered a
little as I anticipated the oil pressure to rapidly rise to an indicated
sixty' ish which would then reduce gradually as the oil got warmer.

Could the oil pump relief valve be at fault ?

Although the oil in the engine is a normal duty grade as per the book,
what is is your opinion as to the use of a 'running in' oil in a new engine,
which is I think somewhat thinner ?


Gentlemen and ladies, I will await your learned responses before I probe any
further..................but please hurry as I won't sleep tonight !!

George in sunny England TC EXU 7548

[joecurto@aol.com]

George do not panic, substitute the gauge (most Smiths units have the same fitting) another spot to check is the actual solid line going to the gauge, lots of times the inside of the tube gets clogged Remove line and heat with propane torch to melt out the sludge, clean line with solvent and blow dry. After refitting you will want to bleed the line. Leave fitting loose on back of gauge start engine and when oil starts to drip out tighten the fitting (use rag to catch oil)

Joe

[Martin Johnson]

George
At first, I thought the relief valve, but after reading Joe's response, it
reminded me of my Austin-Healey 3000 rebuild. Same situation as far as
cranking up the new engine before firing and having the disappointingly low
pressure. In going through a troubleshooting checklist, air in the line was
a possibility. Turns out that was exactly it. After bleeding the line, I
had 60 lbs at fast idle. Good luck.
Martin Johnson
TC3586

-----Original Message-----
From: joecurto@aol.com [mailto:joecurto@aol.com]
Sent: Wednesday, April 10, 2002 3:04 PM
To: george.arber@virgin.net; mg-tabc@yahoogroups.com
Subject: Re: [mg-tabc] Oil Pressure


George do not panic, substitute the gauge (most Smiths units have the
same fitting) another spot to check is the actual solid line going to the
gauge, lots of times the inside of the tube gets clogged Remove line and
heat with propane torch to melt out the sludge, clean line with solvent and
blow dry. After refitting you will want to bleed the line. Leave fitting
loose on back of gauge start engine and when oil starts to drip out tighten
the fitting (use rag to catch oil)

Joe
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service
.

[Robert Grunau]

George,
We are on exactly the same schedule. I am re-restoring TC-8654 EXU and
today fired the engiine. Started first time and I ran it at about 2000 rpm.
Oil pressure on the starter before fire up was 40 psi. Oil pressure running
at about 2000 rpm was 75 psi. I am using 30 wt non-detergent oil for the
first few hundred miles. Will change to Castrol 20W-50 after break-in.
Your oil pressure seems low, both on starter and running. Check the oil pump
relief valve is not stuck open. Then check and replace or shim the relief
valve spring. A 1/4" lock washer, with the set removed, works fine for a
shim under the spring. .
Regards, Bob Grunau
I need some collective wisdom and hopefully just a little reassurance
please .

I am moving well ahead now with my restoration of our TC EXU with the main
wiring completed and this evening managed to fire up the engine. The
restoration has been a long term adventure and I fully rebuilt the engine
some six years ago, including new camshaft, crank regrind, , new shells and
a rebore etc., - maybe I should have left the engine ' till the last, but
having had to rebuild it in the first place as a result of number one piston
going pop, it was only after the rebuild that I decided to get the rest of
the car back up to scratch.

The rebuilt engine has been stationary in the chassis for around six years
and I had given it an occasional turn with the starting handle after putting
a teaspoon of oil in each bore via the spark plug holes. Prior to firing her
up, I primed the oil pump and whizzed the engine over on the starter with
the plugs removed and after a short while the oil pressure gauge registered
20 psi. What is giving me cause for concern however is that after firing up
the engine, the gauge only registered 20 psi and gradually crept up to just
under 40 psi on a fast tickover of approx., 2000rpm It seemed to take ages
over a minute ) to creep up to this. Blipping the engine a little higher
made no difference .

During the engine rebuild I lapped the oil pump end plate to adjust the end
clearance of the gears and replaced its bushes. I recall that I did have
difficulty in removing one of the shafts. Another point is that the oil in
the engine was fresh and clean, but that was six years ago ! I cannot see
however that new oil would make any difference regarding the oil pressure.

Maybe I am just a little too anxious at this early stage, but my
satisfaction on hearing the music after such a long time has been tempered a
little as I anticipated the oil pressure to rapidly rise to an indicated
sixty' ish which would then reduce gradually as the oil got warmer.

Could the oil pump relief valve be at fault ?

Although the oil in the engine is a normal duty grade as per the book,
what is is your opinion as to the use of a 'running in' oil in a new engine,
which is I think somewhat thinner ?


Gentlemen and ladies, I will await your learned responses before I probe any
further..................but please hurry as I won't sleep tonight !!

George in sunny England TC EXU 7548




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[Bullwinkle]

George:

I would verify that the problem isn't the guage first. Get or borrow a
generic oil pressure and temporily hook it up to check the oil
pressure. Also verify that all of the oil lines from the guage to the
banjo on the block are clear.


After refitting you will want to bleed the line.

Why would this be necessary? As someone else pointed out, this is a
closed line. Once the air in the line has been pressurized to the oil
pressure then the guage reads correctly. Even by bleeding the line,
there is still air in the Bourdon tube. (I think that's the name for
the curled tube inside.) Additionaly wouldn't air in the line help
absorb any shock pulses as when starting up?

Also, on home pressurized water systems the pressure guage reads the air
pressure in the tank as its mounted at the top of the tank. This
indicates the pressure the water is under.

Bleeding isn't necessary.

Blake

[Dave & Diana Dwyer]

George

Did you thoroughly clean the (very fine) mesh strainer in the oil pickup in
the sump?

The last time I took an engine apart this strainer was clogged solid with
hard black deposit which was insoluble in anything I could find. Eventually
soaking in paint brush cleaner (a sort of dilute paint stripper) moved some
of it, then I bead-blasted the rest.

Your engine should go up to normal pressure (ie about 60). Personally I
would just use normal 20/50 from day 1 .

Regards

Dave Dwyer
J2, TA, TC

[i.thomson@talk21.com]

> George,

I would guess that you have two "problems", neither of which will wreck the engine but need investigation nevertheless. Firstly, the slowness to comee up to pressure is likely to be down to a partial blockage in the line to the guage. I had this same problem after my rebuild and replacement of the flexible tube from the block cured it. Remove the tube and try to blow it through. Old oil can set solid. It would do no harm to check your guage; put a known good one direct on the block connection if you can. You are on the lower connection aren't you? The upper one will read low! After getting the guage to respond correctly; and no it doesn't need blleeding, try the washer behind the pressure relief valve. Iam just about to try this myself. I have the dimensions for a spigoted washer for just this purpose which I have made and am waiting to try when I get round to it. The question about the oil strainer is also a good one.

Ian Thomson.



--------------------
talk21 your FREE portable and private address on the net at http://www.talk21.com

[i.thomson@talk21.com]

> George,

I would guess that you have two "problems", neither of which will wreck the engine but need investigation nevertheless. Firstly, the slowness to comee up to pressure is likely to be down to a partial blockage in the line to the guage. I had this same problem after my rebuild and replacement of the flexible tube from the block cured it. Remove the tube and try to blow it through. Old oil can set solid. It would do no harm to check your guage; put a known good one direct on the block connection if you can. You are on the lower connection aren't you? The upper one will read low! After getting the guage to respond correctly; and no it doesn't need blleeding, try the washer behind the pressure relief valve. Iam just about to try this myself. I have the dimensions for a spigoted washer for just this purpose which I have made and am waiting to try when I get round to it. The question about the oil strainer is also a good one.

Ian Thomson.



--------------------
talk21 your FREE portable and private address on the net at http://www.talk21.com

[Roger Furneaux]

George, you should get MANY replies to this one (40 psi is OK BTW, the flow
is enormous) but I would say one thing is MOST important: if you have a new
cam, the lobes and followers must be bedded in. You do this by setting a
fast tick-over, and letting the engine run for at least 40 mins (some say 1
hr.) to let everything warm through, and in this time you must NOT "blip it
up". Then, to run it in, drain the oil and replace it with the cheapest,
thinnest, supermarket oil you can get (or use running-in oil, much more
expensive) and start running in for 100 miles, 3000 rpm max, then replace
the oil with more of the same. Do another 500 miles, increasing the revs to
3500, then a) change the oil for something better, b) change the oil filter,
c) back off the head nuts by half a turn and then torque them all up again
in sequence, d) re-set all the tappet clearances. I hope you remember which
cam you used, it could need 12, 15 or 19 thou.

Modern oils such as Castrol GTX are designed to stop engines wearing out, so
they are just too "good" for running in. As to your sluggish gauge, it may
be congealed oil in the capillary: disconnect it from the gauge with the
engine running
until new oil comes out.

ocTagonally

TCRoger

> I need some collective wisdom and hopefully just a little reassurance
>please .
>
>I am moving well ahead now with my restoration of our TC EXU with the main
>wiring completed and this evening managed to fire up the engine. The
>restoration has been a long term adventure and I fully rebuilt the engine
>some six years ago, including new camshaft, crank regrind, , new shells and
>a rebore etc., - maybe I should have left the engine ' till the last, but
>having had to rebuild it in the first place as a result of number one piston
>going pop, it was only after the rebuild that I decided to get the rest of
>the car back up to scratch.
>
>The rebuilt engine has been stationary in the chassis for around six years
>and I had given it an occasional turn with the starting handle after putting
>a teaspoon of oil in each bore via the spark plug holes. Prior to firing her
>up, I primed the oil pump and whizzed the engine over on the starter with
>the plugs removed and after a short while the oil pressure gauge registered
>20 psi. What is giving me cause for concern however is that after firing up
>the engine, the gauge only registered 20 psi and gradually crept up to just
>under 40 psi on a fast tickover of approx., 2000rpm It seemed to take ages
> over a minute ) to creep up to this. Blipping the engine a little higher
>made no difference .
>
>During the engine rebuild I lapped the oil pump end plate to adjust the end
>clearance of the gears and replaced its bushes. I recall that I did have
>difficulty in removing one of the shafts. Another point is that the oil in
>the engine was fresh and clean, but that was six years ago ! I cannot see
>however that new oil would make any difference regarding the oil pressure.
>
>Maybe I am just a little too anxious at this early stage, but my
>satisfaction on hearing the music after such a long time has been tempered a
>little as I anticipated the oil pressure to rapidly rise to an indicated
>sixty' ish which would then reduce gradually as the oil got warmer.
>
>Could the oil pump relief valve be at fault ?
>
> Although the oil in the engine is a normal duty grade as per the book,
>what is is your opinion as to the use of a 'running in' oil in a new engine,
>which is I think somewhat thinner ?
>
>
>Gentlemen and ladies, I will await your learned responses before I probe any
>further..................but please hurry as I won't sleep tonight !!
>
> George in sunny England TC EXU 7548
>
>
>
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>

[George Arber]

Thank you to those of you who sent armfuls of wise advise re. my oil
pressure query . I will have another check this weekend. As a matter of
interest I fitted a new length capillary tube from the engine to the gauge
so there is no problem there.

I will let you know how I progress. Again , many thanks.

George TC EXU 7548