Pb with mecanical oil pressure gauge

[Mich7920]

Hi all,

Have you had any problems with the Classic Quality (Tim Goldthorp) oil pressure gauge?
The 2 gauges gauges that he supplied me ( 1 in exchange ) leaked and filled with oil after very little use.
My car is a serie 1-1965.
My engine has about 10,000km since its restoration.
My oil pump is standard and comes from Barratt.
My oil is a 15/50 "Classic plus" from Penrite.
I warned Tim that at start-up the needle went to maximum and then when running the pressure was 2.5 to 4Lbs.
The manufacturer's feedback is as follows: "Both gauges have been returned to the manufacture and tested. Both are fully functioning. They have advised that an incorrect pressure, above 60, has been applied which has caused the pipe inside to leak. "I didn't need them to tell me that...
Apparently it seems that I'm the only one who have this problem, so what can I do without damaging my engine?
I've gone back to an electric sensor as the original and obviously, with the slow reaction time, I never go above 60.

Regards
Mich

[mgcjag]

Put a test wet guage on your engine to see what actual pressure you have....Steve

[phoenix]

I changed to capilary guage and changed the electrical sender to a 15lb switch and mounted it jwarnig just under the dash out of sight unless you are sat In drivers seat.

[paydase]

Mich,
Your issue may be a too high oil pressure in the circuit, never discovered before because of a failing electrical gauge.
As advised by Steve, you should verify with another mechanical gauge located on the oil filter housing and/or directly screwed on the engine (oil ramp) that the pressure is not unduly high.

When I replaced my original electrical gauge with a wet one on my OTS, I measured much higher pressures but these remain in the nominal range controlled by the discharge valve.
Maybe your discharge valve in the oil filter housing is non functional...

[Mich7920]

Hi
Thank you all for your diagnosis and advice.
The parts have been ordered.
I won't have time to work on the car before a trip of about 2000 km to Chambery in the French Alps. With few motorway sections.
I don't think that having too much starting pressure is dangerous (as opposed to too little) but I would like your opinion or advice on the feasibility of this trip.
Thanks
Mich

[malcolm]

Did you say your running pressure was 2.5 to 4 pounds? Do you mean 2.5 to 4.0 psi, or a different scale of readings? What range does your guage read?
I must be misunderstanding the units you are measuring I think.

[DWW]

I think he is talking bar. 2.7 bar=40psi

[Mich7920]

Hi
Sorry for the unit pressure mistake :
You must read 25 at 40 Lb.
My gauge is the original.

This morning I dismantled the filter head and checked and cleaned the valves.
It's such a simple system, I wonder how it doesn't work.
What I understand:
With a poor seal of the coper relief head there is a leak and consequently the pressure is too low.
But to have a too hight pressure, the valve shoudn't open and at this moment is the spring faulty ?
The other relief valve for the filter, is great. A captive ball and a spring it's simple again.
There is absolutly no trace of rust anywhere.
Could you help me to understand with your own experience ?
( I just bought a mecanical gauge to check the pressure at the head filter. I'll do that further.)
Thanks
Mich

[paydase]

Mich,
Re-reading your initial post, I think that your OP's (25-40 psi when hot, 60 psi when cold) are correct.
Unless you mean 2.5-4 bars (40-60 psi) and 6 bars (80+ psi), which would be rather high. But unlikely as the Classic Quality gauges are with psi.

Maybe the way your mechanical (capillary) gauge has been fitted is wrong (e.g. incorrect threadings or with badly seating seals), or more likely the membrane inside the gauge is leaking, hence oil leaks inside the gauge as you report.

I would suggest that you source a mechanical gauge from another supplier or better a used original one.
Original old Smiths gauges (for MGs, Minis, etc.) can be found on ebay. I myself decided to do so, knowing that new mechanical gauges are sometimes of poor quality as reported by a number of users.
No oil leaks issues in my case.

[Mich7920]

Serge,
I think my pressures are good except sup 60 for the cold start.
I thought also that it was the new gauge, for 1 it could but for two with the same faulty...
I wait for a mecanical gauge to see the real pressure at cold.
Thanks
Mich

[malcolm]

Understand the figures now! I don't think there is anything wrong with 60 from cold. I have a capillary guage, which has been checked against a workshop professional guage at various rpm. It is spot on at all revs.
My cold pressure hits 70 psi - higher than my original guage would read! And it is correct. I imagine my relief valve opens a little late. But it has never caused any problems and doesn't concern me.
Your running pressures are ok, perhaps a tad low but maybe guage error. Even if they are true, I don't think it is a reason not to go on your trip. I know a lot of people who run with lower pressures than that.

[Mich7920]

Thank's Malcolm,
I'll send you a snowball from Chamonix...
Mich