Morris Minor Owners Club

The oil pressure gauge reads 60 on tick over then raises to nearly 90 when travelling.
There's no performance issues that is obvious to me. Is the reading acceptable on my 1961 948cc traveller.

Done so much work on my moggy and it's nearly all done. Think it's time to change the oil pressure valve ( having replaced almost everything else)
But I'm unable to find a like for like one. Seen many but they are different from what I need.
Can anyone advise please. Tried banging head twice but that didn't work !

Never mind what the pressure gauge ‘reads’. What are the actual pressures?

If the above is too obscure - check the gauge before doing anything else!

The oil pressure reading is too high.
What you have shown is not the oil pressure gauge sensor/transmitter but the water temp gauge transmitter.

The oil pressure relief valve is located further down the block just forward of the distributor.
It can be easily identified as a large domed nut.
The valve should open at 60psi but could be the source of your problem if it is seized shut.

what relief valve do you have? I think it should be a cylinder with a taper on one and and a spring as in the ESM link below, if t's one of the aftermarket ball and spring arrangement in my experience they give too high a oil pressure. But as above check the accuracy of the gauge first.


https://www.morrisminorspares.com/engin ... er-p830319

It's been pointed the oil pressure valve is the 2nd photo ive attached. The original photo is the water temp one this will explain a lot. !

A member has suggested to ignore the gauge and check the actual pressure. Surely it's the for the very reason to read. And to get the actual pressure reading. I don't know how to do this so will need to work it out.

What type of oil are you using?

20 w 50 is the oil.

To get the oil pressure relief valve domed cover out of the block is a real ba--ache made even worse by the oil pressure gauge take off.
To get a socket or spanner on the domed cover usually means removing the starter. I re-made a socket (see below) to suit the situation and it allows the domed cover and relief valve to be removed without removing the starter.
The socket on the left is the original modified socket and the one on the right is the later iteration. Both work well.

These indicated pressures are extremely high.
Although the Relief Valve should operate at around 60psi, as I understand the system (and someone very knowledgeable on engines please correct me if I'm wrong), but warmed up and at idle the Oil Pump itself should be incapable of generating more than about 20-25psi, because it's turning fairly slowly. So at that point the Relief Valve doesn't come into it....

The Relief Valve is really for when the temp is cold and the Oil thicker.

I'd have thought that if you're really getting a min of 60psi, then idling with the rocker cover off there'd be oil going everywhere
How much Oil is splashing around if you run it with the Oil Filler Cap off?

Have you got a tyre inflator/pump you can connect to the Oil gauge for a rough check of the reading?

The ideas/ suggestions have been superb.
Thankyou for your patience and the way solutions are offered.

Ours with a new engine generates 50psi hot at idle but doesn't go over 60psi cold, so I expect a good engine would be capable of generating those pressures.

I can't think of much else it could be except the relief valve, its OK to get out once you have removed the starter or I made a tool out of a cut down socket welded to an old 1/2 drive extension a ( much cruder than Phills but works fine) .

Where are you? If you are near Essex you are welcome to borrow my tool.

Wey hey. Think I've sorted it. Gonna do some them there star jumps.........if my hips will stand for it !
Thanks so very much for you very knowledgeable thoughts. Dead chuffed !

lestraveller wrote: ↑Wed Jun 28, 2023 3:41 pm Wey hey. Think I've sorted it. Gonna do some them there star jumps.........if my hips will stand for it !
Thanks so very much for you very knowledgeable thoughts. Dead chuffed !

Well don't leave us hanging, what was it....?

The problem was an incorrect reading of the oil gauge on my dash. The needle would NOT got to zero when ignition off. Should have noticed that the needle it was pointing at 40 before bothering you guys.
So I've replaced it today and all is good.

Glad you found it and its good to get the final feedback when there's been a problem.

At least it was a nice easy fix - we like them!

oliver90owner wrote: ↑Tue Jun 27, 2023 1:54 pm Never mind what the pressure gauge ‘reads’. What are the actual pressures?

If the above is too obscure - check the gauge before doing anything else!

Always my first ‘port of call’. Checking the readings are genuine is low cost, low tech and quite often leads to a simple fix.

Glad you didn’t start by dismantling the engine.