Whats your oil pressure.

[Cubes]

Hi ppls,

Since I have had my RB30DET built up with a clearance checked RB25DET oil pump, I have noticed oil pressure is rather high. Not so much when warm on idle & cruise but mainly with high rev's (warm) & when stone cold.

I am aware the stock guage is a little dodgy but mine does appear to be consistant.

When cold & idling the guage reads spot on 8kg/cm2 (113psi), once driving & cold the guage will rise up to around 8.3kg/cm2 (118psi).

Once warm the guage reads 2kg/cm2 (28psi) on idle, 4.2kg/cm2 (60psi) on cruise (~3000rpm) and 6.5kg/cm2 (90psi) when reving hard (up to 7000rpm).

The 118psi seems extremely high... almost excessive.

The RB20DET never had such a high reading, at most it was 6kg/cm2 when cold with similiar pressures when warm on idle and cruise with the reving hard pressure up around 5kg/cm2.

Is this pressure excessive? I'm thinking maybe the oil filter by pass ball and spring isn't working correctly, I have heard the RB30's do have a high oil pressure when cold + being the motor has been setup with nice tight clearances (blueprinted) this could explain a few things.. MAYBE!!

The initial start of the fresh rb30det I crapped my self as oil pressure was up slightly over 8.5kg/cm2 (possible 20w50 running in oil??), I killed the engine instantly and rang my tuner. He didn't appear to be too concerned.

The motor is running well with now 6,000km's under its belt. No funny noises and the piston slap when cold has now settled.

The first 500km's there was no piston slap then it slowly began to appear, very quietly. Now it can be heard when standing next to the car however it is so quiet you would not really know what it was. My old man didn't even notice it and didn't know what noise I was talking about so it is a real light piston slap that totally dissapears once the oil pressure has dropped hence the car is up to operating temp.

I have actually grown quite fond of the slight piston slap noise.

Post your oil pressures people.. I am especially interested in those that have a RB25DET oil pump.

[RB30-POWER]

I've found that lighter weight oils, usually read higher than a thicker grade oil, in almost all conditions. Don't know if that somehow fits into this discussion.

[Cubes]

I noticed a definate drop in oil pressure with the lighter 10w30 over the running in 20w50.

Not much though.. Maybe 0.3kg/cm2.

The most important difference between the running in 20w50 & motul 10w30 is when I put it on the dyno around 1000km's the running in oil appeared to thin out really easy when given a few power runs. The motul doesn't. Consistant oil pressure with the motul. Maybe this is why they state on the bottle of running in oil not to put the motor under high load.

When I go synth I have a bottle of 8100 5w40 here that will be in for 1000km's then I will be dropping in some 15w40 Motul 300v as I have heard of good results on the RB's, apparently it helps quieten down the top end and any piston slap some how, running the 15w40 over the 10w40 that is.

[raist60]

Mobil 1. Going only by the factory gauge im having exactly the same pressures as you, if not slightly more.

My motor still works?

[Cubes]

Its all looking good.

10psi for every 1000rpm..

You run the 5w50 Mobil 1?

[raist60]

Yup

[tang0]

my experience is the same as Cubes in relation to drops using thinner oil, and the pressure at revs / idle / warm / cold

rb25det

cheers