High oil pressure

[finestjammy]

Hi All

My oil pressure has started to read 60psi when warm. Admittedley the needle bounces around so I'm guessing it's the sender. It's started 'bouncing' around 60psi though rather than 30 though. Anything to worry about? Or just the sender? I'm guessing it's low oil pressure that woul be a concern and not high?

[tuscan66]

finestjammy said:

Hi All

My oil pressure has started to read 60psi when warm. Admittedley the needle bounces around so I'm guessing it's the sender. It's started 'bouncing' around 60psi though rather than 30 though. Anything to worry about? Or just the sender? I'm guessing it's low oil pressure that woul be a concern and not high?

cant see a prob, the chim I just purchased runs about 80 degrees and iddles @ 30psi and at 2k sits tad over the 60 psi and running correct oil grades I would be more worried if was down to 25 hot and lower on iddle however expect some one will have some diff views

Edited by tuscan66 on Saturday 28th May 11:53

[blitzracing]

On the preserp' engine the oil pressure release valve is known to stick, and there is a mod where instead of using a cylindrical "piston" valve, you replace it with a ball bearing type. It sticks because the soft aluminium valve housing becomes scored over time so the piston cant slide up and down smoothly. I don't know if this applies to serp engines as the oil pump is different.

[finestjammy]

blitzracing said:

On the preserp' engine the oil pressure release valve is known to stick, and there is a mod where instead of using a cylindrical "piston" valve, you replace it with a ball bearing type. It sticks because the soft aluminium valve housing becomes scored over time so the piston cant slide up and down smoothly. I don't know if this applies to serp engines as the oil pump is different.

Thanks, it's a preserp so I'll take a look at the valve to see if anything is untoward.

[Number 7]

IME the pressure relief valve generally sticks open, so you're left with no oil pressure when you re-start the engine. As Blitz says, the soft aluminium housing can get damaged by crap in the oil, rather than the steel cylinder of the sliding valve itself. If it really has stuck, you'll need to remove the pump cover to sort it. However, before doing that it might be an idea to undo the retaining bolt/cover for the valve and see if the spring and cylinder drop out. If they do, chances are that it's the gauge at fault. I would also avoid the tadpole style mods to the valve, as these have been known to cause problems as well.

[tuscan66]

what is the common pressures for serp and pre serp just as a matter of ref cheers

[spend]

...before doing anything get a garage to stick a mechanical pressure test gauge in the oil switch hole to check the real oil pressure against the gauge.

I would add it's not always easy to tell the state of the PRV just by disassembly, I've had perfectly fine ones that are real buggers to get out so you might think that they are jammed...

[Number 7]

tuscan66 said:

what is the common pressures for serp and pre serp just as a matter of ref cheers

Much depends on the state of the engine, oil used etc. but my hot idle (1K rpm) is 25psi, and over 2.5k rpm is 40 psi. Measured with a proper capiliary gauge, using Motul 15W 50 300V comp. I think the serps are somewhat higher than this due to the crank driven pump.

[tuscan66]

Number 7 said:

Much depends on the state of the engine, oil used etc. but my hot idle (1K rpm) is 25psi, and over 2.5k rpm is 40 psi. Measured with a proper capiliary gauge, using Motul 15W 50 300V comp. I think the serps are somewhat higher than this due to the crank driven pump.

ok thats good my serp runs idle hot 30psi and at 2.5k sits on 60psi may drop a little if reaching 90 degrees (rare) gauge readings tho lol