Morris Minor Owners Club

I have just changed the oil on a 1098 engine (20/50) and I now have a much higher pressure. This is measured on the installed smiths gauge that was untouched and now reads over 80psi on start up..What are the consequences of too high pressure?

I have changed makes of oil so this is almost certainly the issue. Is it advisable to change the oil?.

What was it before? (When first started after the previous oil change).

Was the previous grade 20W? Is this high pressure at tick-over or higher rpm?

What is the running pressure when at normal operating temperature (both at idle and rated engine speed as per the manual)?

Excessive pressure will obviously load the oil pump more than at a lower pressure. Apart from that excessive oil pressure (likely rather more than this) might not be good for the engine bearings - think here of how a slightly leaking water tap can wear away the seat to the point of a continual leak!

The pressure was around 75 on start up and settled down to 70 ISH when warm when under power. It's a recently rebuilt engine. It stays high as I have seen before ona freshly built engine

My plan is to change oil and filter again to different make of 20/50 oil

I personally would not worry about the oil pressure especially as it is a rebuilt engine.
No harm will come to the engine with the oil pressure specified above.
If you are worried about the oil pressure take a coil off the oil pressure relief valve spring.

Update. I ended up with another oil and filter changed which returned the pressure back to the lower levels. I am not clear why, but it was possibly due to a change in oil manufacturer used.