Engine swap options

[DCRE - Sarge 5 ton]

Hi,

I have a 1984 M923A1 with the NHC 250 that has some issues and needing a rebuild at the very least. I am looking into the options for swapping the engine with something with a little more power to pull hills. Not looking for a hot rod, just a little more sauce. What would you guys recommend?
Swap a small cam n/a NHC 250 back into it?
Put in a big cam turbo NHC 250?
8.3?
Cummins 400, 350, 300?

Let me know your thoughts and recommendations. Thanks!

 

[hethead]

Hi,

I have a 1984 M923A1 with the NHC 250 that has some issues and needing a rebuild at the very least. I am looking into the options for swapping the engine with something with a little more power to pull hills. Not looking for a hot rod, just a little more sauce. What would you guys recommend?
Swap a small cam n/a NHC 250 back into it?
Put in a big cam turbo NHC 250?
8.3?
Cummins 400, 350, 300?

Let me know your thoughts and recommendations. Thanks!

If you're sure you need to pull it, then I'd look at something with a turbo because, why not? but I just turned up my rail pressure to 200 psi, shimmed the governor to 2400, put in new injector screens and the NHC 250 really changed it's attitude. Big girl's got some "grunt".

 

[DCRE - Sarge 5 ton]

If you're sure you need to pull it, then I'd look at something with a turbo because, why not? but I just turned up my rail pressure to 200 psi, shimmed the governor to 2400, put in new injector screens and the NHC 250 really changed it's attitude. Big girl's got some "grunt".

Nice! Thank you for the info, have you had any issues after giving her that much grunt?

 

[hethead]

I joined a facebook group called "Cummins 855 enthusiasts" and asked around. There are a bunch of old retired truckers with decades of experience working all kinds of 855s. The general consensus is that the small cams like to rev a bit. Some "ran them at 2400 all day for 20 years" kinda thing. And that 200 psi is a pretty safe pressure for a small cam. Bigger injectors are better (higher flow, less pressure) but 200 on stock ones is still most likely to last hundreds of thousands of miles. I do run a pyro and keep it under 1000 degrees. Some of those guys ran them hotter (around 1100) but I'm playing it a bit safer. I haven't put enough miles on it to know yet, but I expect it'll be just fine for many years f I keep the revs up above 1800 and don't let it get too hot on the long grades.

 

[simp5782]

Too much grunt on a small cam and they tend to round the cam or torch a piston

939s it much easier to put a big cam in them

809 it is much easier for a turbo addition or another small cam