Oil pressure
Turbo Mini Forums

Hi guys,
Got a worrying one, Just fitted a oil pressure gauge and well at idle (warmish) the pressure is at about 80(psi) i think when i rev it the pressure drops..... and moves around alittle only drops to about 60ish but still i would of thought the pressure would INCREASE as the oil pump is turned faster...... my mini turbo the pressure increase with the revs and the same on my kit car....

Help....

that seems very high on idle, it could be opening the relief valve hence dropping.

wind down the pressure on idle to around 30ish when hot and i bet it will be different and rise when rev'd.

What car/engine?

Sounds like the PRV is sticking. Sounds like its taking alot of pressure to open, and then not fully closing once opened?

Does temperature of the oil seem to make any difference to the pressure?

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1/4mile in 13.2sec @ 111 terminal on 15psi

Engine is a 1380 morspeed engine with MED head. The PRV i changed awhile for the ball bearing type thing. Not sure on the oil temp. How to i wind the pressure down?? is there such a think as a adjuster?

Thanks
Alex.

I've had funny oil pressures when using the ball bearings for the RV. Put a standard one back in and it'll work fine I reckon.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

put some black tape over the gauge and ignore it till the engine blows?!

did you shorten the spring when fitting the ball?

I have had this,

I belive it is caused by the ball, the ball pops of its seat when it reaches pressure and as its smaller than the apperture goes to one side, and create a hysteresis type effect.

on my car you can see just as the preasure reaches the relief break off pressure(55psi) the oil gauge fluctuates about 5 psi then settles as the revs rise at about 50 psi.

Avonbar I belive sell a relief valve kit tith a bit in it to keep the ball centralized to couteract this effect.

also every suposed "cooper S ball and spring" kit i have ever delt with needs the spring cut down, I also prefer to use the std spring rather than the stiffer S spring as the std one seems to give a more stable pressure in my opinion.

cut the spring down a little at a time, putinf the cut end away from the ball, if you go a little too far just pack the spring out with a couple of washers inthe nut thingy that holds the assy in.

Is it worth fitting one of these
http://www.minispares.com/Product.aspx?pid=35963
along with a standard spring and possibly a standard plunger?

No i didn't shorten the spring, i orderd the ball and spring from Minispeed years ago and i asummed that it would be correct. I should learn really.

i'd just cut the spring as those adjustable thingys can weep oil a bit, although the balls can be a little bit inconsistent I still prefer them as they don't tend to stick. IMO better to have 10psi variation around 50psi than have a std one stick wide open

as i said earlier, get the hot oil pressure down a bit and you should see a significant improvement.

Im sure its not the gauge. It used to be in my kit car and read fine in that then i swaped it for another one as i wanted to keep the full face gauge. So i think its good, was alittle worried about having an air lock but it should of pushed any air out by now i would of thought.

Cooper S ball and standard non-S spring (as recommended above) and you will get a lower idle pressure (that will be just about right). The S springs are too strong - hence why people cut them down.