Has anybody had trouble with oil pressure gauges and readings?
I installed a digital gauge and worked fine I was getting around 35 at idle and 50 running.
Over a short drive it kept dropping to where idle was at 0psi and running around 20!

Thought may have been a bad sender or gauge so I had them both replaced and it just did the same thing.

Any thoughts?

Maybe someone has fitted a ball in the relief valve instead of the standard plunger.
Sometimes with cold oil the spring can slip around the ball as it lifts with pressure, it then doesn't seat properly.
Easy fix- fit a proper plunger instead.

Otherwise, it could have a plunger, and a bit of swarf has jammed it partly open.
You need to undo the big cap, take the spring out and see what's what in there.

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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.

Sorry to be a newb but where's the relief valve?

Just to the left of the dissy under number 4 cylinder.

Same spot the sender gets screwed into?

It is about 2 inches below the oil feed line to the filter and takes a 1" socket.

ahhhhhh ok found it! thanks a lot! will undo it tomorrow and check it out

Any joy??

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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.

The mini god lol
Took it out, no ball just a cup and spring like the pic. Not much mess but cleaned everything and put it back and started the car and quickly rose to around 48 psi at idle. Didn't have time to take it for a run as usually that's when the gauge drops so will confirm 2 Moro

No joy!!took it for a drive and was good running around 50psi idle around 18psi. After around 10mins dropped again around 8psi at idle

Would stretching the spring help rapa's situation in getting oil pressure up? Anyone tried this, or is a different spring needed?

Mark

You can put washers under the spring to increase tension.

That only bumps up the maximum cold pressure.
More likely the age of the engine is the issue. Might have to try a thicker oil as a temporary fix.

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Too many cars, and too little time.

what does the spring actually do?
and Id rather figure out a permanent fix