Low Oil Pressure on a fresh overhaul

As far as break in for a new motor run it hard and limit idle rime

 

Oil pressure should be higher than that. Maybe, when they had it apart, a small hunk of gasket or silicone or dirt got in the sending unit passage. I'd find the sending unit, and remove it and check it with another gauge. Was it more before you had it rebuilt? Maybe newer trucks run lower oil pressure. My old Cummins motors ran 60 lbs, and Formula's were at least 50.

 

Specs are 15 psi at idle and 35-40 psi at rated RPM. Ours all idle hot around 20 psi at 600. At what RPM are you idling? You can set the low idle with the cruise swtiches, it'll go down to 500, but they usually idle rough at 500. ISX idle a lot smoother at 600-650 rpm.

For break in, just drive it. Don't idle much and don't lug it.

 

Oil temp at 220 when water at 180?

 

Change the oil cooler thermostat

 

It is amazing how well main and rod bearings last today. Pretty much every bearing roll we do for a customer is complete waste of money because the bearings are still in really good shape. Therefore, when you replace them, the oil pressure isn't going to increase all that much. There are a lot of places that contribute to loss of oil pressure in an engine over the course of time. Main, and rod bearings, cam bearings, rocker shafts, jake solenoids, air compressor crank bearings, turbo bushings, oil pressure regulator, oil pressure relief and the oil pump itself. Depending on how much you replace during an "overhaul" can have little or huge effect on oil pressure afterwards. If all you replaced from the list above is the main bearings, I would not expect any noticeable gain in oil pressure.

 

2007 ISX in my KW oil pressure runs about 16 at idle and 35-40 under load.Temps are around 180-185 coolant and 215-225 oil

 

Is there any blue smoke after sitting, and, or is it going through any oil? If no, I'd say you are back to normal operation. I'm still answering yes to both questions, and my overhaul was 4 months ago.