ISX oil pressure problems

[Therealarw]

(09-29-2023 )SquareOne Wrote:  Whats the history on this engine? Ever rebuilt? Major repairs lately? What about mileage, engine type (i.e- CM871, CM2250, CM2350, CM2450), etc? We will need info before any suggestions can be provided.

Also, how long have you owned this setup? Do you have any prior knowledge on how the engine was treated before you ended up with it? What truck is it currently installed in?

We bought the trucks used about 3 years ago. There was a lot of stuff that wasn’t done on them as far as maintenance. I worked on them a lot just to get them all back into shape. The motor that’s in it is a CM2350. It had a camshaft lobe go flat on it in a couple of spots. Put a new camshaft in along with new cam bearings and some of the rocker arms that were starting to pit on the rollers. Fuel pump camshaft had gone out on it also but the oil temps getting hot was happening prior to the fuel pump going out.
I currently have it on an engine stand and I put a motor we had out of our wrecked truck put in the truck with the motor that was overheating.
I ended up pulling the #4 main bearing cause I had actually put mains and rod bearings in 2 months prior. There was some scoring from the fuel pump camshaft I’d imagine. But I recently pulled the #4 after I got it out and it wasn’t on the copper. Even had the dealer do an oil sample and it came back clean. Also weirdly enough we were able to drive the truck Bob tailing it and it never lost oil pressure, once we had it hooked up to a trailer and loaded is when oil temps wpukd rise up and once it hit 235 on oil temp while driving it just completely shut off.
40-45 lbs of oil cold. Once it warms up it drops up to about 20-24 psi. When you’re on the throttle it shoots up to about 38-45 lbs of oil. Engine has never been taken apart it has about 800,000 miles on the motor. So the only thing I haven’t really done was actually pull the head, pull the pistons/ liners out etc. so that’s what I was wondering was the way to go about getting everything cleaned out. It seized up the turbo twice. And so that’s why we stopped messing around with it and used a different motor. Now everything is working fine on that one while on my free time I plan on going through the overheating one. Coolant was also staying at 185 constant, would only get hotter if the driver was pulling a hill
List of what was done to it.
Camshaft
Camshaft bearings
Couple rocker levers
Oil pump
Main bearings
Rod bearings
A couple of turbos
Oil cooler
Oil thermostat.