Morris Minor Owners Club

I cannot see that anyone is frowning upon the specifications given for oil pressures in the Morris Minor workshop manual Pt No: AKD530 (14th edition) which are 60lb/sq in when running and 15lb/sq in (minimum) at idle.
Those reading are to be aimed for (with the idle pressure higher if possible) and which are not always attainable.
The attainable oil pressures will totally depend upon the condition of the engine and the engine oil used.

Of course, I'm well aware of the adage "Teach not a parent's mother to extract The embryo juices of an egg by suction" but please bear in mind that oil viscosity is highly dependant on its temperature. Scroll down this link to the lowest chart to see the variation; https://www.kewengineering.co.uk/Auto_o ... lained.htm
So the oil pressure you see is highly dependant on the oil type and its temperature. A further point is that if your pressure is high (say over about 55psi) then the pressure relief valve is open and a lot of oil IS NOT GOING AROUND THE ENGINE. A consistently high pressure would indicate to me that either the oil is too cool or a lower viscosity would be an advantage.
I have a temperature gauge fitted to my 1098's sump and in the winter I find difficult to get to 50C; with the front of the sump and one side blanked off I can get it finally up to 65C after about 20 miles brisk driving. (Its an on going experiment.)
At the other end I've only got to 95-100C once that was on a hot day (about 25C) after a couple of hours up the A1M towing a trailer as around 60mph (true GPS read) and even then I found afterwards the sump was down to half full so high temps were no surprise. That old 1965 Gold Seal engine was well worn and drank oil and could only give 40psi at 60mph and 8psi on the tickover with oil at 95C - but it was fast! It was faster than the oil tight engine I've replaced it with.
So I'm fairly relaxed on oil pressures. The "A" Series engine is a tough old beast and even when worn but with good compression and with the carb and ignition timing set up right it'll go well even if a bit rattley.
Regards from MikeN.
PS The rhyme above ends "That good old lady can the feat enact Quite irrespective of your kind instruction”.

Rather than start a new thread, and apologies for bumping this one, is the oil pressure switch screw thread (into engine block), in keeping with those of the engine and gearbox, 1/8" NPT, and not 1/8" BSP?

The thread in the block is 1/8" x 27 TPI NPT parallel.

Note:
A 1/8" x 28 TPI BSP parallel tap will screw into the threads in the block.
There is so little difference between 27 & 28 TPI that both will work for this application.
Because the adapters usually have a taper thread there is no problem with using either.