Whats the normal oil pressure psi I should be getting?

Just wondering as it usually sits 3/4 of the way. (70psi ?)

most of the time as soon as I start the car the pressure will rise up to about 60-70psi. sometimes up to 90 I think when cold.

However sometimes when I start it it sits at about 20 psi... Will rise up to 40 after some time and when I then drive off after a while it goes up to 60-70psi. is that a worry? I know theres a bit of air in the lines going to the gauge. just wondering if I should worry about it or let it be. drives fine otherwise. Apart form the usual not really wanting to go when cold lol

Pull the oil pressure relief valve and give it a good clean. The air in the gauge line has no effect but random pressure changes are not normal. 75 psi (3/4 mark) is.

Cheers, Ian

Either the valve is sticking as Ian suggested, or it has been replaced with a 9/16" ball. When cold, the high pressure can force the spring to bend and deflect the ball off the seat, giving a scary drop in pressure.
This can be remedied by using a new (straight) spring and fitting a piece of 5/16" dia x 40mm long steel rod inside it.
These days I recommend using the standard valve & spring, not a ball. Less hassle....

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Ian, you say 75 psi is normal. When I start my mini it will sit around 75psi until it warms up, at which point it idles around 50psi, and drives around 70-75psi. Should I be concerned with a warm idle pressure of 50?

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1998 Rover Mk VII
2001 Honda CBR 929RR (street)
2014 BMW S1000RR (track)

Warm idle pressure of 50psi is just fine.
Even 20 is OK at idle if the motor has a fair few miles on it.

The oil light fitted to lesser Minis comes on at about 8psi! It's a bit too late really if that comes on when driving along...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Oil light coming on is to prompt you to look at your pressure gauge

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David L


My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

Um.. if you owned an 850 or a Mini Deluxe, the light was all ya got...

I always thought an oil LEVEL light would have been more useful for most A series owners. After all they do like to drink a bit of oilz.
Back in the 60s BMC reckoned using 1 pint (~600mL) in 400 miles was `normal' for a 1098 during warranty period.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.