M923A0/A1 vs. M923A2? (Possible Future M923A0 owner)

[71DeuceAK]

Latest crazy idea:

I might be a future M923A0 owner. Found one back where I grew up that belongs to a fellow Steel Soldiers member. It came from the Camp San Luis Obispo National Guard, and considering that I was born in San Luis Obispo and grew up in Atascadero I'm thinking that even though I've always wanted an A2 with the 8.3 Cummins (better MPG and more modern) I may pick this one up, he's selling it but not in a big hurry either. I'd love to have a truck from where I grew up, and would like to eventually move back to. It was probably here when I was born, in the late '90s. (Dating myself here).

I'm sure this has been talked about plenty before, and there's a never-ending flaming debate about it on some of the M939 Facebook groups, but what's everyone's opinion on the A0/A1 vs. the A2? Of course I know the straight M923 has the dual tires (unless upgraded) and the A1 has the singles and those both have the 855 NHC250 Cummins, whereas the A2 has the 6CTA 8.3 liter Cummins and the CTIS. But other than that, what are your personal preferences, and why? (if possible, list reasons). What problems have you seen or heard about with either?

I've heard many stories of the NHC250 having piston liners go BANG, especially when run hard and I've heard it's pretty cold-natured (mind you, I'd consider daily driving one of these trucks. In the winter. In negative temps. In Alaska. In Fairbanks.) I've heard the 8.3 isn't as reluctant to start in the cold (granted, nothing likes to start at -40F ambient temp). I've heard many people say the 250 is more reliable.

So in essence, I've heard good and bad things about both, understandably. What's your opinions/experiences, good and bad, and why? I'm curious as someone who is just now considering a 250-powered truck.

 

[98G]

No strong preference either way. Choose based on overall condition of the truck unless you're going to drive it enough for the fuel efficiency to be a game changer.

You're going to want a block heater either way in your climate.

 

[Nomadic]

The NHC250 is going to be a better in some cases because you wont have turbo lag. In situations where you need all the torque near off-idle RPM's, the NHC250 will be the better choice over the 8.3L.

What is the MPG difference between the NHC250 and the 8.3?

 

[red]

Fuel economy will depend on your right foot and what RPM you are willing to drive at on the highway. I'm getting a little over 6mpg in my wrecker (NHC250) cruising at 2000rpm, some are getting 8mpg with the 250 cruising at a little bit less RPM (empty cargo) and others who drive it at redline get 3mpg.

250 wins at low rpm driving, 8.3 wins at highway driving and will get better fuel economy when empty. 6-12mpg range with the 8.3.

250 is a heavy duty engine and rated for 1 million mile expected lifespan, 8.3 is medium duty and rated for 500,000 mile expected lifespan. 250 will throw a rod if it's driven at over 2100rpm regularly compared to 2600rpm with the 8.3.

Other main difference is the CTIS on the a2. Have the money to maintain it then it's a nice feature to have when the truck goes from pavement/offroad regularly.

 

[lindsey97]

I regularly get 7.1 mpg in my M923A0 or A1 with NHC-250. I would really like to own a nice A2. However I feel that there is nothing wrong with the NHC-250 and it's design. Big slow moving heavy parts trumps high speed lightweight parts most of the time. After recovering quite a few trucks, and working on them, I conclude that lack of service and lack of coolant testing causes the vast majority of liner failures in the NHC-250 engine. When properly maintained, I believe the NHC-250 is as dependable as any other man made mechanical object.

 

[Nomadic]

I like the one million mile service life design. The gas milage difference sounds significant when compared by all things equal except the engine. If the NHC-250 gets 3MPG on the freeway (guessing R'd out would be 55 MPH), thats worse. I plan to use mine at least 12k miles a year. When the cost of diesel goes up, that extra few mpg could save in the short term. But long term the NHC-250 has double the service life, a big win right there.

 

[98G]

My experience with A0 and A1 trucks is 5-6mpg, full or empty, or even towing a 2nd truck on towbars.

A2 trucks vary more widely. I've done as well as 12mpg empty, and as poorly as 6mpg with a 2nd truck on towbars.

Either motor will live essentially forever properly maintained.

 

[74M35A2]

I don't know if I would go as far to say the 855 is a million mile engine. Not that any MV is ever going to make it 1 million miles. I don't even know if anybody has 100,000 on theirs here, or anywhere else. I think the Detroit Series 60 was one of the first mass production production motors to regularily make 1 million miles. Here, a while later, you can now get (pay for) up to a 1 million mile warranty on Cummins ISX 15L engines. I have also heard a 600,000 target for the 8.3L's, like mentioned.

8.3's can get double the fuel mileage. They may be a pinch more reliable, just looking for how many have been apart here (nearly none) vs the 250. 8.3 has no throttle response from a stop light idle without being turned up. 250 has good low end power. 8.3 starts easier/cranks faster. 250 sounds like a truck, 8.3L sounds like a school bus, well, because that is one of its applications. 8.3L pulls good once turbo wakes up, all the way up to 67mph stock. 8.3 can safely reach higjer RPM than the 250. 8.3L is a much newer engine design, and therefore has much better fluid sealing. They usually don't leak anything, anywhere. 8.3L is lighter. CTIS is way cool, I don't even know where my valve stems are. Truck checks its own tire air and inflates if need be within the warm up period or by the time I am pulling out of my neighborhood. The 250 does seem to suffer from cylinder liner degradation via coolant, and the 8.3 does not for some reason. That can be a scare since these trucks are now decades old already.

These are all opinions. Read each sentence carefully and make your own decision. You will notice most opinions align, and do not contradict each other, regarding the comparison of these two.

 

[ROCKWELL-C60]

8.3 driving procedure on soft anything. Put transfer case in low range drive forward, if reverse is needed put in neutral put transfer case in high range back up then put back in low, drive forward again cause 8.3 won't pull on soft ground and you can't use reverse in low, try this in mud hole. Nhc 250 leave in high because you have all the low end power you'll every need.

 

[Csm Davis]

Biggest difference between 855ci and 8.3L is weight on front of the trucks, both are rock solid engines if maintained properly, I believe that the 855ci has a few more problems reported because most are 10 years older and sat around rusting the cylinder liners longer. Now I do think that the 855ci suffers from being over spun, lots of broken rods. I believe the 8.3L is a better setup for a cargo or tractor that runs the highway or plays in the mud. But I hate CTIS I has to many things to go bad and parts are expensive.

Sent from my SM-G900V using Tapatalk

 

[Gunzy]

The best thing I can recommend is this: Go try to find and test drive both engine configurations yourself. This will give you a personal feel for how they drive against each other. Then and only then you will have a better understanding of the performance differences between the two. Most peoples preferences are going to be their personal ones. I drove both before buying. 1st I drove an A2 w/8.3 and not ever having driven one was wasn't sure what to expect. I thought the 8.3 was a slug. But, when I drove the NHC 855 truck I knew in 20 seconds that I prefered the bottom end torque it had and the decision was made. Now, yes I know the 8.3 is easy to turn up the power, but when you do that you will reduce economy and life. Such is the world of hot rodding. I want my MVs stock because they tend to be more reliable. But what it all comes down to is your personal preference. Nobody is going to be able to make that final decision for you. So, have fun in the search and enjoy your machine reguardless of which one you choose.

 

[74M35A2]

Bring a cat and a spool of string.

 

[lindsey97]

Csm Davis brings up some good points, especially about weight. I could see the 8.3l being a better candidate for a winch truck, using the lighter motor to offset the weight of the winch.
Another difference between the 2 trucks is sound/noise level. A NHC-250 makes much more noise and is significantly louder both in cab and out than a 8.3l equipped truck. I feel that one should wear hearing protection, or at least have a hard top if driving a NHC-250 for any length of time.

 

[sandcobra164]

Having owned both and still owning a NHC 250 powered truck, I would lean towards that. In your climate in Alaska however, the 8.3 may be the drivetrain you are after. Either way, you need to let the oil warm once started in such a frigid climate and use a block heater. My NHC 250 started just fine at positive 20 degrees using the ether start in about 6 seconds the other day. It had a low 450 rpm idle for about 2 minutes and went back to normal. It runs a 50/50 waste ATF / Fresh Diesel mixture that it has run on for years. I agree, buy depending on condition of the truck.

 

[71DeuceAK]

Interesting opinions!

As for service life and MPG, I would quite frankly daily drive it wherever it would fit and if I could afford the fuel! And as far as the million mile service life, I fully intend on putting that to the test, I would daily drive the snot out of mine until it absolutely quit and even then just swap in a new engine. Whatever I have to do to keep one of these fine pieces of history on the road, I'd do it, barring being financially out of luck. The eventual hope is to also have a spare engine and transmission on hand as well, for obvious reasons.

 

[snowtrac nome]

buy condition they are all good my preference goes to the big 855 as said before torque monster. I have driven both up by Fairbanks in - 40 first off invest in a fuel burning heater or you will be cold and the windshield will never defrost, secondly you will need a coolant engine preheater IE a block heater or a combustion coolant heater, other wise it wont start once you shut it down. 0-30 synthetic oil is also a must as 15w40 pours like Vaseline at those temps. The trucks are rock solid but at those temps uncle sam made a lot of changes to make then tolerable in weather that cold.

 

[Jbulach]

I wouldn't worry much about which motor or tires the truck has as much as overall condition. Unless your doing a lot of highway driving the A0 will suit you just fine for your first MV.

 

[red]

Cummins rated the 855 series engines as million mile motors, same as their competitors do (Detroit, CAT, ....). Working on class 8 trucks saw quite a few trucks roll through the shop with that series of motor with that many miles and 1 was a NHC 250 with the Cummins 'altitude compensation kit' (turbo). Wanted his motor rebuilt and had just rolled over 1.3 million. So the 855 series is certainly capable of it.

That being said, the 855 series is not meant to cruise at 2000+rpm all the time. Military tends to just drive the truck at redline (2100-2300 depending on how they set it) and not care about the shortened lifespan of the engine.

As others mentioned a block heater will be necessary with either motor in your location, or building a fire underneath the engine every day.

 

[71DeuceAK]

Yeah, for my first MV I think it would do fine in that role. I'm also considering this one because of its history, even though it'll be in AK at first it'll be a piece of history. Snowtrac Nome, you've driven the M939s up there? Would love to eventually get together with a few other like trucks and go play in the snow, etc.

 

[Jbulach]

Are there any trucks that come up for auction in Alaska? Would think there would be less bidding competition up there, you could spend more on the truck and less on shipping, plus likely already set up with some of the arctic goodies. I wouldn't even rule out the old standard shift trucks to get your feet wet...