Morris Minor Owners Club

Thanks for replies and sorry I only just read them so am starting new topic with my answers. The engine is standard sidevalve. When I sold the ALTA head (which was on a different engine) I had to have the standard head refixed on my original engine because I had chewed up the studs trying to get the head off before, and at the same time I had new gasket,valves and springs fitted. It's after that that it has been showing excess oil pressure on the (also standard) gauge. Where is the oil pressure release valve? I am familiar with it on a 1098 but not the MM.

Oh and the gauge does read 0 when engine off.

what is it showing?

What do you call excessive oil pressure?
Mine reads a steady 80 on the run and at tickover when the engine is cold and may drop down to 65 - 70 if the oil is really hot after a long run.
It's been reading this sort of pressure ever since it was rebuilt 12 years ago and runs perfectly.

It reads max cold.

Looks like an external sunvisor on Mr Dorset's car. Is that original on a lowlight?

The oil pressure relief spring is in the oil pump so it is a sump off job to change the spring. 80 psi on a cold engine is not unusual especially on a rebuilt engine, mine started out at 80 and has gradually dropped off to about 70psi and 60 at tickover after a brisk run on the motorway.
Check the oil gauge pipe and gaskets for any leaks. Go for a drive and gradually increase the engine revs, then when the engine is hot switch off then start the engine again and watch how quickly the oil pressure builds up. If it goes just up to 80 then I would not worry, if it goes straight up to 80 then you may have a blockage in the pressure relief valve. I would give Graham a ring as he has more experience with high oil pressure than I have.

Yes. that's an original split screen sunvisor fitted on my Lowlight.

Aha. I havent taken it for a run to get really hot since rebuild so we'll see. Happy Christmas!

The plot thickens. Oil pressure will be considerably higher on a 'new' engine. Short runs never allowing it to warm up properly are detrimental. MM oil gauge of course only reads to 80 psi.

You are aware of the correct running-in proceedure?