Morris Minor Owners Club

Hi all - I've had a Smiths capillary type oil pressure gauge professionally fitted on my '62 1098 saloon and am a bit concerned that the oil pressure is a bit low. On initial start up it's around 60 but when fully hot and say, pulling uphill it's around 50, or just over, at about 50mph. At a similar speed but when just 'cruising along' on the flat it's somewhere between 40 and 50.

On tickover, when hot, the o p drops to around 20, I am guessing here - due to the lack of specific calibration

The engine sounds as sweet as a nut and pulls nicely as far as I can tell (I've never driven or even been in another Moggy so I've nothing to compare it with!!)

I've read on here and elsewhere that a healthy O P should be between 60 and 70 when cruising along between 50 and 60 mph. I know, before anyone says it, it's my own fault for fitting an oil pressure gauge as, what you don't know about, you can't worry about!

One other small issue. A pal-cum-neighbour, whose had plenty of classics, recons that the 'clear' tube that goes to the oil pressure gauge should always be filled with oil. He's 'bled' it twice from behind the gauge, while the engine has been running, but each time after a short while the pipe is mainly clear of oil when the engine has been switched off for a while. He recons that that could be affecting the seemingly low(ish) O P readings. I'm more of the view that that's got nothing to do with it as surely the oil in the tube leading up to the gauge will just drain back into the engine when the engine is at a standstill. Who's right on this one?......and do I need to start saving up yet for an engine rebuild?

Thanks, as ever, for any input from you guys.

Though I do not know your engine and what condition it is in the figures you have posted are more than adequate and you should not be worrying about the displayed oil pressure.

As regards the oil tube - drain back so that the tube is clear/empty is normal. When the oil is pushed up the tube is matters not a jot, the air poundage will be the same as the oil pressure poundage - the only difference is that you can compress air whereas you cannot compress liquid.

Just enjoy and do not worry about rebuilding the engine

Only worry when the oil pressure warning light comes on at idle.

As PTH, don’t worry at the moment.

You are assuming the gauge is accurate - which it may not be.

Ford engines of the same era coped with a pressure of about 40psi, IIRC.

Plain bearings only need about 5psi to maintain a lubrication film - but pressure will drop from input to the extreme parts of lubrication - think a short hosepipe versus an extremely long one.

It is possible that there is leakage through the pressure relief valve (apparently not common on these engines).

You don’t quote your source of oil - some brands can lose more viscosity, with increase in temperature, than others.

Most likely fault, if the oil light comes on at tick-over, is the switch - unless there are other signs of a worn out engine.

Don't worry, you have the gauge, just look for changes. If you see the pressure suddenly drop, you know that you have a problem. Mine went from 50lbs to 20lbs all of a sudden. I stopped immediately and got a tow home. The problem turned out to be the centre main white metal coating flaking off. No damage done. I swopped the bearing then rebuilt the engine a couple of thousand miles later.

Its not the pressure reading, its a change in the reading that you are looking for.

Thank you kindly, gentlemen...…..I shall sleep a little easier tonight

No, seriously though, your wise words are much appreciated. Thanks.