Multifuel Engine life - the facts from Uncle Sam

[Neosin]

Yea yea, me too i'll take one or two for my hotrod deuce project... lol

I was talking to a guy that drove multifuels in Vietnam. He said what has already been posted here about full speed and little care for the truck. He also mentioned that his motor pool would not work on a Duece with a driveability problem. As in if it idled rough or cut out at full throttle, they didn't want to mess with it.

However, if the engine was blown, they would install a brand new one. So, what did they do if a Duece was running, but not 100%? He said their trick was to park the truck next to the motor pool, remove the intake mushroom, soak a rag with gasoline and stuff it into the intake up to the filter. Start the truck and hold the throttle to the floor. He said a rod would pop out of the block "within 10 seconds normally." They would then remove the rag, walk into the maintenance area and tell them the truck had died. Maintenance would change out the entire engine in about an hour or so and they were on their way again with a good running truck.

How wide spread this was is anybodies guess. My reason for posting it is this. Numbers can lie if not understood and applied the correct way. A CO writting a report to justify his money will use numbers totally different than a factory rep trying to justify his companies product. Those of you with mulit fuel engines shouldn't be freaking out. Do the required maintenance, don't drive it like you stole it and it will take care of you.

But, if you feel you can't live with an engine of unknown quality in your truck, you can drop them off at my house. I live in Giddings, Texas. Come on over.

 

[Neosin]

Listen don't talk to me about the MAN patented hypercycle, i invented it... ok ... See what you do is ya take you some KY jelly... then.... ah never mind you old timers won't get the joke anyway....

I put over 17,000 miles on my deuce over a 2-year period with thousands of highway miles loaded to the limit (32,000 lb gross with trailer across the Rockies for example). It still starts and runs beautifully, but has developed a knock and low oil pressure as a result of FDC and IP problems, which were caused by rust from the old second hand fuel tank, which I have expanded on elsewhere.

As for being "primitive" of design, I beg to differ, its combustion process is based on the MAN patented hypercycle, which is both quiet and efficient. Much has been posted before on this site about that also.....

 

[Neosin]

My Uncle too! LOL He said watch the thumbs and keep your gun loaded.

Yes, 3000 rpm on the engine in stock form would be a ticking time bomb waiting to unleash the Rod Bomb! lol

Upon buying my deuce, I was chided by my uncle, who served in Vietnam in some sort of transportation role. He first told me how horrible the trucks were to drive, particularly that they were difficult to steer and to watch my fingers and thumb...

But he also said that in his unit, most of the trucks had not only the fuel turned up, but also the governor... They were running them closer to 3000rpm most of the time... He did mention that this seemed to cause a lot of holes in the block, and recommended I not mess with the governor.

Chris

 

[jasonjc]

You all keep comparing the muit too the cumming,powerstoke and dramax. Those were all built in the last 5-15 years. The muilt was designed back in the 50's. Hello alot of things have changed in the last 50 years. Including eng design. Why do think you can do/get the same power out of a 50 year old eng as a brand new one. Go get a "CHIP" for the muilt and see what that does for you.

 

[Scrounger]

JasonS
"There is a governor to limit engine rpm. I have to believe that the engine manufacturer/ designer set this limit. If the engine was not capable, why set it so high? It is not unreasonable to assume that it will be run against the governor.

I have a hard time believing that this engine's stroke contributes to it's short lifespan. The 5.9 Cummins has a 4.812" stroke; the multifuel has a ~4.8" stroke. The cummins is not noted for throwing rods and LOTS of folks rod and drive them hard. The cummins also has smaller bearings and smaller oil pump (based on the oil filter capacity). What is it about the multifuel that makes it materially different (inferior) to the cummins? I am not trying to start a pissing match; just trying to understand why. "

The limit for the engine is 2600 rpm; however one can over speed the engine when going down hill. In service it is not uncommon to have the fuel and or governor on a truck fiddled with.
As far as the stroke of the engine one must remember what the bore size is also. When comparing the multi fuel to a Cummings there is a difference in the size of the pistons and that translates into mass. As I’ve already posted I think the engine is quite remarkable that it can run at 2600 rpm as well as it does. Just look at the NHC-250 Cummings in the 800 series. They redline at 2200 rpm and Uncle Sugar was even kind enough to place an over speed light in the taco graph in the 818s to remind one of that. The multi fuel engine is a very reliable engine as long as it is serviced and not driven like it is stolen. Don’t change the oil, run it with out coolant or allow the engine to over speed when going down a hill; don’t be surprised if the engine comes apart.

 

[K45]

I am still learning about these engines. i think the idea is very cool and looks like ti is just a matter of some deisgn flaws to make it work better, but as far as the failures that is reported which this posted was started on, and the responses afterwards. I could easily see it being a user error and preventive maintainence issues were the main problems for what these motors had.

The other big thing I notice is you can compare hoping in a deuce or bigger and think it is going to drive like a smaller 1 ton truck. It is great how well the durmax, powerstrock and cummings perform but how well would they truly be on a bigger truck? The ideal think would be to compare motors from a peterbilt, Kenworth, and a Mack to the Deuce. A closer apples to apples comparison. Because if you want to just throw any diesel into the ring my VW 1.9 TDI diesel is quick, fast and pulls the size vehicle it is in. I am still learning and would to learn more abou what problems have been repaired and performance increases these motors have. Thanks

 

[Neosin]

I don't think any one is "comparing" them to one another. Just using the new engines as reference in regards to RPM, Load, Power band. My comment was to take note as to a little shorter stroke, lighter weight pistons (not light weight) stronger/lighter rods, better cut/balanced crank and you could pull 3000 ish RPMS and i'd bet with a good turbo setup you could make 200 - 240HP, and around 600ish torque quite easy on the multifuel.

Before they used stroke to help the turbo, today's turbo's don't need a long stroke to make the power they once did. If you can push 10 or 20 more PSI in boost pressure you can gain the power that way rather than limiting the engine RPMs so low and get some of that hill climbing RPMs back up in the 3000 RPM range.

Taking a look at a powerstroke. 7.3L diesel, it's better then the newer 6.0L in towing and reliablitly. Mainly because there is far better heads on the 7.3L and less moving parts to go wrong. Plus being on 2valve per you don't get the side loading on the valves as you do with the newer 4valve diesels.

I think maybe what they might of beening trying to do when designing the engine was one "be multifuel" that takes a nice piston design that happens to have more mass to hold up to the temps required when buring multi fuels. This adds mass to the rotating assembly Thus lowering the effective RPM range. So some limits was built in to do many jobs. However it moved the truck along just fine in most cases. Another issue is RPM = Wear. The higher the RPM the quicker it dies. In the 50s' when they designed this engine RPM really was a killer. Today we have far better rings, Oils, etc hell oils today are 1000 times better than in the 50-60s.

Thus why a powerstroke can spin 4000 RPMs and get away with it. Just using very good oil in your diesel will help it last. I'd use rotella T for anything diesel if your not gonna use Amzoil. But you better keep it fresh 3000 - 5000 miles change it. Because oil really is the life blood of these engines.

But in war time, these engines, one wasn't driven like we drive them. Two oil wasn't changed as the needed to be. three i'm sure these things was driving in the upper RPM range 80ish % of the time which when you look at the oil used, etc these things just didn't last long. I don't think any engine would have. Even knowing you could build an engine that would take the abuse it would of cost at least twice as much. So what do you do, make a cheaper engine and replace it as needed or make a better engine? There is your rock and a hard place.

You know something fun would be to put this engine in something else, like a F350 or something just for the fun of it. If you took care of it you could get i bet at least 1 million miles out of it before you ever had to do anything major. I think that would be a very fun project to prove how well these things really are. How cool would that be lol this multifuel engine in a normal truck.

You all keep comparing the muit too the cumming,powerstoke and dramax. Those were all built in the last 5-15 years. The muilt was designed back in the 50's. Hello alot of things have changed in the last 50 years. Including eng design. Why do think you can do/get the same power out of a 50 year old eng as a brand new one. Go get a "CHIP" for the muilt and see what that does for you.

 

[Neosin]

Your right, they do make F700s F650s, etc that use the normal powerstroke. These are big trucks but still not big rigs. But your right, i don't consider the powerstroke or the duramax "real" diesel engines. I consider them Hybrid engines. Real diesel engines are 4 or 6 inline cylinders, i would consider the cummins engine a real "mini" diesel. Your VW diesel (which i love) is what i'd call a micro hybrid diesel.

I am still learning about these engines. i think the idea is very cool and looks like ti is just a matter of some deisgn flaws to make it work better, but as far as the failures that is reported which this posted was started on, and the responses afterwards. I could easily see it being a user error and preventive maintainence issues were the main problems for what these motors had.

The other big thing I notice is you can compare hoping in a deuce or bigger and think it is going to drive like a smaller 1 ton truck. It is great how well the durmax, powerstrock and cummings perform but how well would they truly be on a bigger truck? The ideal think would be to compare motors from a peterbilt, Kenworth, and a Mack to the Deuce. A closer apples to apples comparison. Because if you want to just throw any diesel into the ring my VW 1.9 TDI diesel is quick, fast and pulls the size vehicle it is in. I am still learning and would to learn more abou what problems have been repaired and performance increases these motors have. Thanks

 

[K45]

I wonder if the deuces themselves and the multifuel engines would last longer if there was an extra transmission or gear. This would double the amount of normal drive gears and lower the operating rpms so they would not be running so high. Just an idea tell me if I wrong.

 

[JasonS]

Well to say stroke without talking about the rods and pistons is the reason why your not understanding it. The rods and pistons on the multifuel are in no way to be considered "high rpm" style. Nor the crank.

Your just looking at the stroke, so many other factors come in to play. The commins engine has far better designed pistons, rods, crank etc thus why it can do what it does. If someone (and i might try this down the road) took a multifuel and had some pistons, rods and crack made for it/custom cut and balanced i believe you could get at least powerstoke rpm range 3000 - 3500 range red line. However some other work might be needed as well. You would also be talking about a lot more horse power and torque coming out of the engine as well.

No, I understand what you are saying. However, I don't think that the Cummins was designed for high speed, either. It was first a tractor engine.

Objectively, I just don't think that the multi was ever a very good engine.

 

[dburt]

We need to remember also that often the low bidder gets the job, and the engine and truck design had to fullfill alot of roles, so a multi-fuel engine and a multi-purpose truck were just a big compromise to satisfy alot of different needs. It did alot of things pretty good, while not doing any one thing very very well. I have seen deuces with miles in the 60-70,000 range when they were surplussed out of the service and they are still running well. So just take care of it, used good oil and change it often, keep it running cool, don't drive like it's still Uncle Sammy's, and you will get good service out of it.

 

[DDoyle]

Since this thread seems to be becoming one of "what if" and guessing as to the reasoning of the engineering of the Multifuel....I'll remind all of something - and then I'll toss my .02 cents in.

First, as explained in detail in another thread, the Multifuel in the deuce began life as a gasoline engine, then in the fifties it became a diesel, then came the Multifuel after Continental got a license from M.A.N. for the multifuel technology.

The turbo on the LDT has nothing to do with power - it was installed solely to clean up the exhaust in order to meet emmissions standards - this too is well documented (not conjecture).

With the facts out of the way, I'll toss in my .02 on the service life in Vietnam issue and blame the dusty road conditions and suspect there were problems in filtration.

Regards,
David

 

[littlebob]

Thanks, DD for bringing up this post. I'm sure a lot of these engines will do better in private hands, but the other consideration for us is: how often has been operated and how long have they sat without being run? I have a feeling mine sat for a long time before I got it and with my luck as soon as I get it cosmeticly the way I want it I'll Through a rod or something. Hope I'm wrong but all of our vehicles have different pasts.
littlebob

 

[M543A2]

Well, I have heard the 427 was a problem, but I will be a hard one to convince the 465 is a problem. We have several trucks with them, and they have been very dependable for farm use.
I find it hard also to equate the gloom and doom of the write-up with the success of the same engine in White 2-155 farm tractors. It is not at all unusual to find them with 8,000 to 10,000 hours on them and still going fine. In my area of the Midwest, the tractors are seen as a good investment. Our neighbor has one with close to 10,000 hours that is the smoothest running tractor you could ever hope to own. The bottom end torque makes his Allis tractor of comparable power seem like a dog. They will go get the White every time over the Allis if they have a choice. He also owns a four wheel drive John Deere for which my son and I rebuilt the engine. He saw the multifuel crank I have in storage and was amazed at how much more metal was in it than in the Deere crank. BTW, we will NEVER touch another Deere for engine rebuild. What a nightmare, with the engine buried under the cab so far, between fuel tanks, etc. Without our M543A2 wrecker, it would have been impossible. Deere owners have to be paying much higher labor rates for repairs due to their designs being so "mechanic unfriendly" to work with!!
Regards Marti

 

[darknessvanquished]

The multi-fuel is a nice piece of military diesel nostaglia. Modern diesel techology is light years ahead of the multi-fuel, so comparing a new diesel to the multi is kinda unfair. The multi-fuel paid its dues and time moved on. With that said, there's a reason the A3s were upgraded to CAT power. lol

 

[Nonotagain]

The multi-fuel is a nice piece of military diesel nostaglia. Modern diesel techology is light years ahead of the multi-fuel, so comparing a new diesel to the multi is kinda unfair. The multi-fuel paid its dues and time moved on. With that said, there's a reason the A3s were upgraded to CAT power. lol

Google up Cat 3116 engine problems then we'll talk about that engine.

cat 3116 engine failures - Google Search=

The International DT466 engine has been in production since 1975 and still running strong.

International Engine Group

 

[Recovry4x4]

The multi-fuel is a nice piece of military diesel nostaglia. Modern diesel techology is light years ahead of the multi-fue

So are the trucks they are in but they are so appealing. I don't see too much of the newer stuff running on the swill that these multifuels run on. There really isn't much that you can compare with the multifuel in an apple to apple basis.

 

[darknessvanquished]

So are the trucks they are in but they are so appealing. I don't see too much of the newer stuff running on the swill that these multifuels run on. There really isn't much that you can compare with the multifuel in an apple to apple basis.

The ability to run on "damn near anything" is what makes the multi special. It does sound "meatier" than newer diesels as welll-the sound is the one thing that I have always liked about deuces.

 

[clinto]

So are the trucks they are in but they are so appealing.

YES!

I love my classic Mopars for just this reason: They are simple. They are not over bushed, over insulated, overly complex machines which separate you from the road. When you go around a curve, you feel the road surface in the steering, as the tires lose their traction in braking, you can feel it in the pedal, etc. I wouldn't want this everyday, as good fuel economy, a good stereo and most importantly A/C are important but as a weekend fun cruiser, nothing beats it.

I see the Deuces as being the same.

The multi went away because of the EPA and the M44 series went away because the contractors wanted Uncle Sam to buy something else. Guess they couldn't make any more money on the old Reo's so it's off to the races with the current FMTV's (Family of Moderately trustworthy Vehicles).

 

[wreckerman893]

The bottom line is that deuces are tougher than woodpecker lips.

They are not quiet.

They are not comfortable.

They are not the most fuel efficient truck in the world but they get decent fuel milage for what they are.

They will run on stuff that would FUBAR just about any modern engine.

They will get you home on a wing and a prayer.

They can be worked on by just about anyone with a basic knowledge of mechanics, basic hand tools and the knowlege of the quirks of the truck.

The brake system sucks.



I would not trade any deuce for ten of the modern NATO wanna-be vehicles that the US military had forced on them by contractors, crooked politicians and other idiots that don't understand that GEE WHIZ crap on a truck will get you in more trouble than it will get you out of.

I got out of the Army just as the HETT's, FMTV's and other vehicles were being fielded.
I once got into a very heated debate with an OSHKOSH rep when he started blowing sunshine up our butts about what a great system the HETT was.
I called BS (very loudly) on him and told him any line haul truck with a V-8 Detroit engine in it was designed by an idiot and built by a moron. And don't get me started on that nightmare of a trailer that drags along behind it. STUPID STUPID STUPID
I told him I could have put together a tank hauler that would be twice the truck for half the money using a Freightliner and Fontain heavy duty trailer.
I spoke with a lot of guys that did tours in Iraq and Afgan......if a vehicle can't be repaired or recovered immediatly it is blown in place.....your tax dollars at work.
I have driven deuces in from the field with no alternator, dead batteries, no brakes or with a busted drive shaft using front wheel drive.....try that in the new ones.
The KISS principal applies to trucks just like it does with everything else ........Keep It Simple Stupid.