2000 Cummins signature 600 engine.

N14 Cummins is a bulletproof motor. Not 600 hp, but I had a 435 and besides oil changes put in one injector in 6 years.

 

Holy thread resurrection.

Seeing that the op was asking about a sig 600 not a n14 and the fact this was almost 5 years ago , im perty sure it dont matter much anymore
Lol

 

What is worse is that the N14 wasnt bullet proof at 525, the block fretting was a big issue when they cranked the torque, and why Im almost certain the Signature was released on full kill.

 

Is there anybody who has a signature ISX? I'm looking at a truck with a 99 Signature ISX 600 hp. Engine rebuilt at 400k .

 

Block fretting was due mostly to abuse, and extended oil changes. If takencare of it will last 1-1.4million. I have one 625hp/2250tq and 995k. Still clean oil samples and one set of injectors.

 

You can tell yourself that, but oil changes have nothing to do with main bearing caps moving around when the engines are lugged.

You ever wonder why you don’t see fretting on big cams, even hot ones? It’s becuase they aren’t pulled below 15-1600rpm.

 

You are right about lugging. I

 

Lugging combined with extended oil changes and increased bearing clearance for extended period is a major cause. I feel not properly shifting is a issue. I don't run mine under 1500, not even my detroit.

 

ISM seemed to fret mains even more than the N14. Most that failed we're ones that were set to pull around 1300 RPM and max govern of 1800 RPM. Basically fleet speced trucks. Lugging kills them.