Oil Pressure

[Richard Fritz]

Tom:

I would have to agree with Rick Waters' suspicion that the gauge may be responding sluggishly due to the thin line to the gauge. That was the case with my TC. Bill Bollendonk asked how quickly the gauge returned to zero when the engine was shut off. Sure enough, it was very slow.

Richard Fritz, TC6649, Longmont Colorado

----- Original Message -----
From: Tom & Emily Wilson
To: mg-tabc@yahoogroups.com
Sent: Tuesday, May 20, 2008 2:33 PM
Subject: [mg-tabc] oil pressure


I am looking for suggestions before I dig into this problem. Newly rebuilt
XPAG with 300 miles on it. This morning it took one minute for the oil
pressure gauge to register any pressure at all. Then it slowly rose to
about 35 pounds. After driving a bit it went up to 40 and stayed there.
Same situation occurred with each engine restart, after it was warm. This
hasn't happened before on this engine.
This engine has not had oil pressure above 45 pounds since the rebuild.
We're working on it this coming Thursday - oil change, retune carbs,
etcetera. And hopefully find the cause and fix this problem.
Any suggestions?
Tom Wilson
Zionsville, Indiana USA
TC0272 & 0273

[Non-text portions of this message have been removed]





[Non-text portions of this message have been removed]

[mark heathman]

If the line to the head is installed up side down (which it can be)
your oil pressure will read low.
I would just as soon not go into the details of how I happen to know
this. I can also tell you that
if you do this on assembly following a major rebuild finding the
error gives real mixed emotions.
Feeling stupid but real happy about it.
200 cold is to high. I would go back to the original spring as you
now know that was not the problem.
I would also drop your oil to a 20/50 I have never heard of some one
running 20/60.
Mark TC 5707

[mark heathman]

This was poorly worded. If you are pulling your oil pressure from a
banjo bolt at the head this is wrong and will yield a very low oil
pressure reading. Your oil pressure guage line should be connected to
a banjo going into the main oil line in the block, the lower banjo
bolt when looking at the external line feeding the head.

On Jul 2, 2008, at 7:42 AM, Phil Marcell wrote:

> Mark'
>
> What do you mean up side down? My TC is a little low.
>
> Phil
> ----- Original Message -----
> From: Mark Heathman
> To: mg-tabc@yahoogroups.com
> Cc: Mark Heathman
> Sent: Tuesday, July 01, 2008 7:12 PM
> Subject: [mg-tabc] Oil Pressure
>
> If the line to the head is installed up side down (which it can be)
> your oil pressure will read low.
> I would just as soon not go into the details of how I happen to know
> this. I can also tell you that
> if you do this on assembly following a major rebuild finding the
> error gives real mixed emotions.
> Feeling stupid but real happy about it.
> 200 cold is to high. I would go back to the original spring as you
> now know that was not the problem.
> I would also drop your oil to a 20/50 I have never heard of some one
> running 20/60.
> Mark TC 5707
>
>
> I am using the free version of SPAMfighter for private users.
> It has removed 96 spam emails to date.
> Paying users do not have this message in their emails.
> Try SPAMfighter for free now!



[Non-text portions of this message have been removed]

[jrbrookes@aol.com]

A big thank you for all your help and advice. I will let you know when I
get to the bottom of this puzzle. In the meantime please tell me what's inside
the gallery to rocker box pipe and how do you tell if it's the right way up?

Best wishes,

Bill TC3034






[Non-text portions of this message have been removed]

[joecurto@aol.com]

The pipe is the same top or bottom, you want to make sure there are no
obstructions in it, I sometimes remove it from the engine and heat it
with the propane tourch and melt out all the old crusty oil, let it
cool down and flush with solvent and blow with air. Make sure no one
has blocked the holes in the banjo bolts.

Joe


-----Original Message-----
From: jrbrookes@aol.com
To: mg-tabc@yahoogroups.com
Sent: Thu, 3 Jul 2008 7:00 am
Subject: [mg-tabc] Re:Oil Pressure






A big thank you for all your help and advice. I will let you know when
I
get to the bottom of this puzzle. In the meantime please tell me what's
inside
the gallery to rocker box pipe and how do you tell if it's the right
way up?

Best wishes,

Bill TC3034

[Non-text portions of this message have been removed]

[joecurto@aol.com]

Mark we are all in agreement BUT originally the factory took pressure
reading from trhe cylinderhead side of the pipe.

Joe


-----Original Message-----
From: Mark Heathman
To: Phil Marcell ; mg-tabc@yahoogroups.com
Cc: Mark Heathman
Sent: Wed, 2 Jul 2008 8:22 pm
Subject: Re: [mg-tabc] Oil Pressure






This was poorly worded. If you are pulling your oil pressure from a
banjo bolt at the head this is wrong and will yield a very low oil
pressure reading. Your oil pressure guage line should be connected to
a banjo going into the main oil line in the block, the lower banjo
bolt when looking at the external line feeding the head.

On Jul 2, 2008, at 7:42 AM, Phil Marcell wrote:

> Mark'
>
> What do you mean up side down? My TC is a little low.
>
> Phil
> ----- Original Message -----
> From: Mark Heathman
> To: mg-tabc@yahoogroups.com
> Cc: Mark Heathman
> Sent: Tuesday, July 01, 2008 7:12 PM
> Subject: [mg-tabc] Oil Pressure
>
> If the line to the head is installed up side down (which it can be)
> your oil pressure will read low.
> I would just as soon not go into the details of how I happen to know
> this. I can also tell you that
> if you do this on assembly following a major rebuild finding the
> error gives real mixed emotions.
> Feeling stupid but real happy about it.
> 200 cold is to high. I would go back to the original spring as you
> now know that was not the problem.
> I would also drop your oil to a 20/50 I have never heard of some one
> running 20/60.
> Mark TC 5707
>
>
> I am using the free version of SPAMfighter for private users.
> It has removed 96 spam emails to date.
> Paying users do not have this message in their emails.
> Try SPAMfighter for free now!

[Non-text portions of this message have been removed]

[Tom & Emily Wilson]

I fired up the rebuilt "restored" engine for TC0272 this afternoon. It
started on the first crank and seems to be running pretty nice.
Oil pressure on the engine is still somewhat low. I'm using Valvoline 30
weight racing oil to break the engine in, and pressure at idle is 32 pounds.
At 3000 RPM it goes up to 40 pounds.
The only two things I didn't repair in the engine are the oil pump and the
rocker arm assembly. So the options on oil pressure being low are these two
things plus the pressure relief spring.
Is the pressure at a low enough level that I should be concerned about this?

Thanks.
Tom Wilson
TC0272 & 0273


[Non-text portions of this message have been removed]

[Clive Sherriff]

Tom,

Some seem content with 10 on tickover and 40
running. However I must admit I prefer to see
my oil at 50 / 60psi when running hot, and
about 20 at hot tickover in road use. (Racing
oil? - for a higher compression road or racing
engine I'd want a full 60 / 70 psi very soon
after my 25 psi at tickover revs)

Possibly a weak pressure spring - take the cap off
and fit a few small washers under the spring and
see what this does, (you can then replace or stretch
the spring if this seems the problem, otherwise
maybe the pump lid is worn and needs regrinding
dead flat to stop internal back oil seepage, but be
warned that less than 0.0015inch clearance
between the lid and the gears may well cause
a seizure when hot.

Rocker arm is easily checked by putting a thin
shim under the rear rocker post to block off the
oil supply and running for a short time (30 secs
should be enough, to see what that does to the
pressure.

Clive
Oxford UK
==================================

----- Original Message -----
From: Tom & Emily Wilson
To: mg-tabc@yahoogroups.com
Sent: Wednesday, February 25, 2009 8:21 PM
Subject: [mg-tabc] Oil pressure


I fired up the rebuilt "restored" engine for TC0272 this afternoon. It
started on the first crank and seems to be running pretty nice.
Oil pressure on the engine is still somewhat low. I'm using Valvoline 30
weight racing oil to break the engine in, and pressure at idle is 32 pounds.
At 3000 RPM it goes up to 40 pounds.
The only two things I didn't repair in the engine are the oil pump and the
rocker arm assembly. So the options on oil pressure being low are these two
things plus the pressure relief spring.
Is the pressure at a low enough level that I should be concerned about this?

Thanks.
Tom Wilson
TC0272 & 0273

[Non-text portions of this message have been removed]




[Non-text portions of this message have been removed]

[aprper@sbcglobal.net]

Tom,
Your inquiry is very timely as I have some concerns about low oil pressure on TC 6305 (fully rebuilt engine, less than 1000miles). Just this afternoon I used a donor oil pressure gauge and psi went right up to 50 lbs, and as the engine warmed up it actually went to 55-58 psi., idle at 1,500rpm. The reason for this test was to validate the reading of my in-dash oil pressure gauge. (Not certain, however, that the donor gauge is accurate, but I don't have the means to use another hydraulic source to test the donor gauge).

The in-dash gauge was reinstalled and psi reached only 40 lbs, after the engine was warm also. Previous to this test I had shimmed the oil pump relief valve spring by thirty thousandths, using washers that did not interfere with the operation of the valve (hole was larger than valve stem). Up to that point I had been using 15W-40 weight oil, and switched to 20W-50 which was recommended by Lawrie Alexander (local MG guru). The switch to 20W-50, strangely enough, did not produce the boost in psi that I thought it would as the psi reached was actually lower!

I installed the donor gauge at the point of exit of the oil from the engine block (not the head) to the flex line (leading to the coupling which has a long oil line going to the in-dash gauge. Could it be that this small diameter line is too long, causing a pressure drop between the engine and the in-dash gauge? My engine has a new valve rocker shaft, and all the rocker arms were re-bushed. When I had the car's instruments refurbished, I can't recall whether or not the o.p. gauge was tested for accuracy, so that could be suspicious for the low pressure. Also, my engine has a newly rebuilt blower that takes engine oil to a metering valve to lubricate the shaft. I have that set to a slow drip of one drip every 5 seconds or so. Lawrie believes this is not the source of the problem.

So, what to do now? My feeling is to verify that the donor gauge is correct before delving into more draconian reasons. I'm going to ask Larwie for his comments, first. I'll let you know what he has to say.

Andy in Sacramento
TC6305

----- Original Message -----
From: Tom & Emily Wilson
To: mg-tabc@yahoogroups.com
Sent: Wednesday, February 25, 2009 12:21 PM
Subject: [mg-tabc] Oil pressure


I fired up the rebuilt "restored" engine for TC0272 this afternoon. It
started on the first crank and seems to be running pretty nice.
Oil pressure on the engine is still somewhat low. I'm using Valvoline 30
weight racing oil to break the engine in, and pressure at idle is 32 pounds.
At 3000 RPM it goes up to 40 pounds.
The only two things I didn't repair in the engine are the oil pump and the
rocker arm assembly. So the options on oil pressure being low are these two
things plus the pressure relief spring.
Is the pressure at a low enough level that I should be concerned about this?

Thanks.
Tom Wilson
TC0272 & 0273

[Non-text portions of this message have been removed]




[Non-text portions of this message have been removed]

[WM HYATT]

Clive -
Racing oils, motorcycle oils, are a good choice for breaking in of flat tappet engines. Such oils have high levels of ZDDP as these engines do not normally use Catalytic converters. Years ago ZDDP compounds were used in oils for their anti-wear properties, but their levels have been reduced over the years as they have been shown have effect lifespan of C. Converter.
Oils with a starburst API "SM" designation (passenger car oils) have a mandated Max of .08% PPM of ZDDP whereas non SM oils such as Racing/Motorcycle oils unconstrained by C.C mandate typically still are available with much higher levels of ZDDP. E.g. Tom's Valvoline VR1 Racing oil has up to 1300 PPM of ZDDP. Castrol's Syntec 20/50 full synthetic (can should say recommended for Classic Cars) i.e. non Catalytic Conv. cars has 1200 ppm of ZDDP. Brad Penn Grade 1 Racing oil (non synthetic) has 1500pp ZDDP. Classic Car Motor Oil (www.classicmotoroil.com) offers an oil with 1500-1600 PPM of ZDDP bottled by D-A Lubricant Co. www.dalube.com
ZDDP additives such as GM E.O.S,, ZDDPlus, www.zddplus.com, Camshield www.camshield.com are available for initial break-in at each oil change if a modern oil with API SM rating is opted for instead of possibly harder to get & more expensive oils listed above.

Bill
TC4926
Odessa, Fl.
























p

----- Original Message -----
From: Clive Sherriff
To: TWilson@indy.rr.com ; mg-tabc@yahoogroups.com
Sent: Wednesday, February 25, 2009 5:51 PM
Subject: Re: [mg-tabc] Oil pressure


Tom,

Some seem content with 10 on tickover and 40
running. However I must admit I prefer to see
my oil at 50 / 60psi when running hot, and
about 20 at hot tickover in road use. (Racing
oil? - for a higher compression road or racing
engine I'd want a full 60 / 70 psi very soon
after my 25 psi at tickover revs)

Possibly a weak pressure spring - take the cap off
and fit a few small washers under the spring and
see what this does, (you can then replace or stretch
the spring if this seems the problem, otherwise
maybe the pump lid is worn and needs regrinding
dead flat to stop internal back oil seepage, but be
warned that less than 0.0015inch clearance
between the lid and the gears may well cause
a seizure when hot.

Rocker arm is easily checked by putting a thin
shim under the rear rocker post to block off the
oil supply and running for a short time (30 secs
should be enough, to see what that does to the
pressure.

Clive
Oxford UK
==================================

----- Original Message -----
From: Tom & Emily Wilson
To: mg-tabc@yahoogroups.com
Sent: Wednesday, February 25, 2009 8:21 PM
Subject: [mg-tabc] Oil pressure

I fired up the rebuilt "restored" engine for TC0272 this afternoon. It
started on the first crank and seems to be running pretty nice.
Oil pressure on the engine is still somewhat low. I'm using Valvoline 30
weight racing oil to break the engine in, and pressure at idle is 32 pounds.
At 3000 RPM it goes up to 40 pounds.
The only two things I didn't repair in the engine are the oil pump and the
rocker arm assembly. So the options on oil pressure being low are these two
things plus the pressure relief spring.
Is the pressure at a low enough level that I should be concerned about this?

Thanks.
Tom Wilson
TC0272 & 0273

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]




[Non-text portions of this message have been removed]