Keeping in mind that the stock oil pressure gauges are all a bit inaccurate (some read a bit high some a bit low) 12 psi at idle is a tiny bit low. The service manual states at least 14 psi is normal for 5W30 oil fully warmed up. If your idle is even 50 rpm low it will drop the oil pressure on the gauge some.

 

Jennifer it was measured on an external device.

Does the fuel affect this?

The other shop putted 10 l 95 pb fuel in the car, cause they didn't now, so it is mixed with 98.

 

Adriano if this engine is equipped with ARP and ACL crank and rod bearings one would expect they may be built with larger than stock bearing clearances. Depending which oil pump used, this could explain a slightly lower oil pressure at low RPMs. However at higher RPMs the pressure should be more normal. I don’t have a factory service manual (you can download one for free. Google for lots of sites supplying it) to get the expected psi readings at all engine rpm ranges

Typically, recommended oil pressure readings from Nissan for the 350Z are specified at 176 degrees fahrenheit using 5W30 oil made from dead dinosaurs.

By the way, I doubt the octane of the gasoline would have any effect on engine oil pressure.

 

Thank you Jennifer.

This shop, doesn' t now anything about mechanical tuning(I feel like an alien), so they had tried to take out the engine, because of a lot of particles in the oil after second change.

Right now they will change it the third time.

One question, do the ARP head studs have the same torque moment as the oem ones, because one side of the short block was taken out to put out the rod and piston.

 

Particles in the oil is never a good thing! Do they know where they came from or what kind of metal they are? When my dad had a problem like that he would cut open the oil filter to see what was circulating through the engine.

The torque values and procedures for ARP head studs are on the ARP website. It will actually be a less complicated procedure than the oem “torque-to-yield” head bolts.

Adriano, I’m not an expert on these things (unlike German girls who all know what to do with tools and wrenches). I can search out info for you, but we need some of the more experienced and knowledgeable guys here to also help out.

 

It is the third shop right now, they don't now about particles.
Could it be from bearings?

Some other opinions?

 

After 430 km of slow driving this has happened...


http://www.filedropper.com/dsc0901