I’m a bit curious and concerned as to what the correct oil pressure for my stroker ej207 should be. It’s forged with mahle pistons and Manley rods, induction crank etc. I use motul competition v 15w50 and changed the oil recently, however this was the same before. On cold starts I have about 5-6bar on idle, and once the vehicle is up to about 70-80°C , it’s around 5-6.5 bar under acceleration and around 2.5-3bar on idle. I’ve noticed however, when the car is left to idle for a while, once the temp creeps upto about 90°C, the oil pressure runs between 1-1.5 bar on idle, does this seem low? As soon as I pick the revs up to about 1000rpm the gauge shoots to about 2-3 bar. I use both pro sport oil temp and pressure gauges, I did wonder if these had some issues with accuracy as sometimes I notice when I blip the throttle at idle once upto 90°C or so, the pressure drops to 0 for a split second and then back up again. I was going to try a mechanical stack gauge instead, can anyone point me in the right direction to whether or not these readings are normal? The engine runs sweet as a nut with no noises/oil consumption etc. Any help is much appreciated, cheers!

 

Not normal to drop to 0, check the plumbing of the guage. Your pressures are generally OK, I would suspect/hope the drop is down to an incorrect reading. I had this with a cheap guage, dropped to 0 a few times so tested with a mechanical and it was 2+ bar out depending on pressure, prosport are a reputable brand tho so if it was to be the gauge and not the plumbing its faulty

 

Regardless does 1 bar sound normal then? I think the dropping to 0 is a gauge issue, it’s plumbed correctly but I do wonder if the sensor, which is just a generic item is giving up the ghost. Even raising the rpm to 1000 the pressure shoots to 2 bar or so at 90°C. I also had an issue with my pro sport boost gauge which started going up and down all the time regardless of boost so I am hoping it’s just a gauge issue, hopefully the mechanical stack one should show a correct reading.

 

Out of interest, where is the sender, and is it fitted using any t-pieces etc?

 

Depends on the forged build but yes 1-1.5 bar is fine when up to temp and idling. I was running prosport gauges (car is in bits at the moment) and had issues with a generic sender too. However mine would go off the dial like it was reading 20 bar oil pressure. Initial panic but it did it when the car was on ignition.

With it dropping to 0 get the sender changed.

 

The original sender from under alternator, has an adapter which runs round the side of the engine, It then looks to have the oil pressure and temperature sender for the syvecs plumbed into it. I think the original oil temp sensor tap over cylinder 3, is used for the temp gauge readout.

 

Tbf the chap I bought the car off did mention the gauge was a bit dicky, I’ll try the new mechanical gauge I’ve got when I’ve got car back from Bodyshop. It only reads 1 bar at idle around 750-800rpm iirc but as soon as revs are picked up to say 1000rpm gauge shows 2 bar or so. I will add aswell, when the current gauge does drop to zero it’s literally for not even 1/10th of a second before it shoots up again so I do suspect the issue may lie here.

 

This is what the Subaru service manual says about oil pressure on a stock engine at 80°C oil temp
98 kPa / 1.0 kg-cm2 / 14 psi / 0.96 Bar or more at 800 rpm
294 kPa / 3.0 kg-cm2 / 43 psi / 2.96 Bar or more at 5,000 rpm

Obviously your engine isn't stock, but unless the engine builder had has left massive clearances (which would require increased oil pressure) then the above should still be relevant.
If you've got any details on who build the engine then a quick phone call to them would confirm 100%.

 

I’ve spoken to builder and they said it is a little low, however suggested a mechanical gauge/proper oil pressure test before condemning it, plus at 80°C it’s around 2-2.5bar anyway. All these readings are also assuming my temp gauge is correct.