Strange oil pressure readings

[Pied Piper]

I seem to have problems with oil surging, if the oil is any less than max on the dipstick (even just a few mm) my gauge drops oil pressure considerably when turning left, this happens even with a constant engine load.

Is this normal? Or is my engine about to go?

[Nickccc]

Sounds odd.
Change the oil pressure switch first and see what happens, also check
the wiring from the switch to the gauge.
If that doesn't sort it you may have problems at the pump or the jackshaft
drive could have problems. The Jack shaft is a bad design, any shaft with a square
cut out, as in the cerb is seriously weakened. It might also be the keyway attachment
who knows. I'd try to get a look at the pickup in the sump aswell. You'll need a
boroscope through the sump plug, maybe something is bloocking the pickup.

[FarmyardPants]

Might also be worth measuring how much oil comes out at the next oil change, maybe your dipstick is too long?!

[Nickccc]

I was going to say that, thought maybe the dip stick had somehow
come out ot the cap a bit giving a false reading.
Hopefully it's something simple.

Easy test fill with oil till it shows full on dipstick, then put 500ml
extra in, if the gauge doesn't move when cornering then it's the stick
giving a false reading.

Edited by Nickccc on Monday 10th May 22:02

Edited by Nickccc on Monday 10th May 22:06

[Pied Piper]

I hope it is something as simple as that, have overfilled slightly in the past and pressure has stayed good until oil dips below minimum.

Does anyone know what the length of a 4.2 dipstick should be or maybe the distance to the max. marking?

My worry is overfilling and causing damage.

[Nickccc]

I'm sure there was a thread sometime ago where
the oil pressure relief spring could be at fault.
Change it if it hasn't been done for a while.