1984 AM General M931 Cummins motor upgrades

[KAT MAN]

Hi guys

I am looking at buying a 1984 AM General M931 it has the 855 Cummins naturally aspirated I believe. ( I haven't looked at it in person yet)

Is it possible to add a turbo to this motor? ( how easy is it to do and what kind of cost would I be looking at?)


What other power upgrades can be done?

how much power can I add while still maintaining reliability?

thanks guys

 

[Tornadogt]

There is a detailed thread on this information, yes to added power, yes to turbo, no to adding more speed with the exception of larger tires..

 

[porkysplace]

You might get more responses if you have a moderator move this to the 5 ton forum instead of the CUCV forum. Alot of 5 ton guy don't read this forum.

 

[KAT MAN]

thanks for the response, do you have a link?

 

[Tornadogt]

http://www.steelsoldiers.com/showthread.php?28133-818-now-with-turbo-and-pics

 

[98G]

Hi guys

I am looking at buying a 1984 AM General M931 it has the 855 Cummins naturally aspirated I believe. ( I haven't looked at it in person yet)

Is it possible to add a turbo to this motor? ( how easy is it to do and what kind of cost would I be looking at?)


What other power upgrades can be done?

how much power can I add while still maintaining reliability?

thanks guys

You can't really turn up the NH250 very much at all without risking badness.

If you want a gutless turd that just crawls up steep hills even when empty, the NH250 is for you.

If you want a bulletproof engine that will live forever, the NH250 is also for you. Despite my first comment, I really like the NH250.

I personally wouldn't do anything more than dual fuel and a slightly larger button.

If you want something you can turn up and wring out more power from easily without undue risk of badness, start with an 8.3liter cummins.

 

[KAT MAN]

I figured there wasnt much you can do to up the power on these motors but wanted to make sure


The Cummins 8.3 is also a fairly low hp engine I dont think its worthwhile for me to put one in.

Will a Cummins N14 or Cat 3406 fit in the engine compartment?

 

[wreckerman893]

The Cummins 8.3 is also a fairly low hp engine I dont think its worthwhile for me to put one in.

Will a Cummins N14 or Cat 3406 fit in the engine compartment?

You can get 400 HP out of the 8.3 but you need to take it to an old school Cummins guy and have the pump worked on by someone that knows what they are doing. My buddy had the pump adjusted on his M923A2 and the difference is amazing.
Doing the air cleaner and exhaust mods help a lot too.
The 250 has torque but will always be a turd.

 

[jasonjc]

I figured there wasnt much you can do to up the power on these motors but wanted to make sure


The Cummins 8.3 is also a fairly low hp engine I dont think its worthwhile for me to put one in.

Will a Cummins N14 or Cat 3406 fit in the engine compartment?

The N14 should fit as it is about the same block.

It depend on how much power you want. The N14 goes from 310hp 1150ftlb up to 525hp 1850ftlb. The 250 is 250hp 6-700ftlb. You go to big you'll have to upgrade the rest of the drive train also.

 

[98G]

I figured there wasnt much you can do to up the power on these motors but wanted to make sure


The Cummins 8.3 is also a fairly low hp engine I dont think its worthwhile for me to put one in.

Will a Cummins N14 or Cat 3406 fit in the engine compartment?

I just sold a 8.3 replacement block to one of the tractor pull guys. He said he was getting right at 1000HP/2200TQ out of his.... (of course his last block came apart right at the cam...)

If an engine swap is the plan, then a big cam 855 seems like the obvious choice.

Except as is noted above, the transmission isn't rated for much more power than a stock 8.3.

What is it you want to do with the truck? You may want to start with a different platform..

 

[KAT MAN]

I will be using it for a little offroading, driving through the snow and pulling my trailers.

The Cummins 8.3L is 250-300hp stock so it seems like it would take a lot of work to get it to 500-550hp

vs a CAT 3406 or a N14 I get stock with 550-600hp and then put a 10 or 13 speed transmission behind it

 

[jasonjc]

I will be using it for a little offroading, driving through the snow and pulling my trailers.

The Cummins 8.3L is 250-300hp stock so it seems like it would take a lot of work to get it to 500-550hp

vs a CAT 3406 or a N14 I get stock with 550-600hp and then put a 10 or 13 speed transmission behind it

If you do that you will need to up grade the transfer case as well.

 

[jasonjc]

I just sold a 8.3 replacement block to one of the tractor pull guys. He said he was getting right at 1000HP/2200TQ out of his.... (of course his last block came apart right at the cam...)

Yea BUT the tractor pull guy is only going 300 feet at a time, NOT 30,000 miles.

 

[simp5782]

Swap in a dt466. Tons of power. Less weight. Cheaper parts. They are pretty easy to come by. $4000 for a whole box truck. Pull the motor, trans, air seat, radiator, and fuel tank and scrap the rest and get most of your money back. Or make a lil shop out of the box

 

[wreckerman893]

If you do that you will need to up grade the transfer case as well.

For every action there is a reaction. More power means more strain on the driveline until you discover where the weak link is and then you start replacing things.
If you are not going to do a lot of very heavy hauling the 8.3 is more than adequate. I flat towed an M934 with my M927A2 and it pulled it just fine. I had to watch it or I actually got to moving faster than I wanted to on flat ground.
Your mileage may vary.

 

[Bandit02]

I'm seriously thinking about upgrading to a new engine. I looooooove the purr of a 3406B. The NH250 is useless in M931, and what a tractor should be able to do.

 

[KAT MAN]

If you put a 3406B in there please do a write up with pictures on the process and then a video on the finished product

 

[simp5782]

There is a semi here in Memphis with an N-14 cummins for the whole running truck is $5,500 so after you sneak the motor, seat, transmission and fuel tanks, scrap the rest! and get some $$$$ back. If you are interested in it let me know.

 

[Tornadogt]

There is a semi here in Memphis with an N-14 cummins for the whole running truck is $5,500 so after you sneak the motor, seat, transmission and fuel tanks, scrap the rest! and get some $$$$ back. If you are interested in it let me know.

That is a good deal for anyone who is local

 

[simp5782]

If someone wants to grab it up. I can store it for em till they can get here. It says its driveable