Multifuel Engine life - the facts from Uncle Sam

[Scrounger]

There have been some very good posts on this topic. While some swear by the multi fuel some swear at it. I personally believe it is quite remarkable for the time it was designed in. First off the multi fuel engine is nothing more than a long stoke diesel engine that can operate on other fuels. The important thing to remember is that it is a long stroke diesel. Most long stoke diesel engines redline around 2100-2200 rpm. Long stoke engines do not like being over revved. It only takes once and the life of the engine is reduced. It may not happen today, maybe never, but that’s what causes more engine failures in the multi fuel than anything else. The multi fuel engine in most of these trucks redlines at 2600 rpm. I think it is a testament that the engines hold together as well as they do. With that said, I believe that if one were to place a new multi fuel engine in service, change the oil every 3000 miles and never once allow it to go over 2600 rpm the engine would run at least a half a million miles. However if it is over revved at all it will have a shorted life.

 

[saddamsnightmare]

November 30th, 2008.

Gentlemen:

Just as a footnote to my missive above, since January this year the above duece of mine has racked up about 5000+ miles, including one 8 hour 250 mile trip hauling a gen set in the back (MEP023A from Red River Arsenal),and one 14 hour 450 mile trip pulling an M105A2, both at 54 MPH continous except for the few hills. The rest of the time she runs about 12-15 miles per day in city traffic, which is probably harder on her then the road work. The only complaint I have about the normally aspirated LD465 is that it is leaking about 1 to 2 quarts of motor oil per 1000 miles out the flywheel drain hole, all from the rear main seal, which needs changed out, but I have neither the indoor shop nor the means to pull the transmission myself, and the local large truck garages are scared of the deuce (based on size and unfamiliarity, I guess).
The only other noticeable problem is that she finally blew out the smaller, upper exhaust elbow from the muffler, which will be changed out shortly with the drop pipe from the manifold (exacerbated by no cap on the stack in military service & water in the muffler), but other then that the engine has needed very little attention other then normal inspection and adjustments. Among the adjustments, routine inspection and tightening of the short transmission - transfer case driveshaft and all other driveline flange bolts (this seems to be a recurrent problem and has something to do with the design of the driveline itself).
This truck, according to the great Guru of vehicle information, Dr. MedLog, went about 1200 miles in its final 5 years in the military and its two prior civillian owners (BullDogMack13 being the last), and most of her teething problems were to aging of rubber components and old tired batteries, and one new in tank fuel pump.
She probably won't outrun the average deuce, she can't outrun her shadow, but for her size, maintenance record and age (37+years), she has been a very reliable and useful truck, and chances are, she'll make it past 50 with care and access to necessary parts.
For my two cents worth, the Army much undervalued the M35A2 series trucks, they could take loads and beatings that the FMTV's won't or can't take, and I doubt that the FMTV family will make 60+ years in US Army service- the deuces did that. The money would have been better spent rebuilding the deuces with new engines, running gear and any other requisite modifications to bring them up to 2008 standards, then run them another ten or twenty years, the cost would have been less then developing and adapting the FMTV's.

Cheers,

Kyle F. McGrogan

1971 Kaiser Jeep M35A2 Wo/W "Saddam's Nightmare" Desert Shield/Storm and Vietnam Veteran Truck.
1968 Johnson Corp M105A2 Cargo Trailer
1967 Hercules MEP023A Gas Gen Set APU
1963 Swiss Army Cargo Unimog S.404.114 MB

 

[cranetruck]

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.....

 

[smgman]

Hello everyone . I am 100% new to the Duece world and just purchased my first Duece a month ago she is a 72 am general with whisler turbo . Shows 68,000 and some change on the odometer seems to runs good . I am waiting for filters and hope to get a little better performance after all filters are changed.


Love the forum looks like a wealth of info I need . Looks like I will be spending alot of time here reading and learning .



Jay

Woodstock Md.

 

[ETHOS]

this is cool, lots of good information and real world knowledge available

 

[Neosin]

I don't see how anyone could of looked at the multifuel engine as being one
that would take the field abuse. After being inside one they should of just went with a tried and true 4. Less moving parts, etc. It's funny if you look at the design it's almost like they went with a 4 design then went to 6. Maybe the 4 in the size they tried just didn't make the power. (I find it hard to believe) Shock in a valve system I would bet is what sent most of these engines to the grave yard. Blown head gaskets would of been from over boost conditions on long hauls with loads. Of course now days we have turbos, wastegates and electronic boost controllers to try and solve these problems.

I've thought about doing some trick turbo install with a variable vein turbo this would make a lot of things better. For one i could lower the compression ratio down to 16:1 or 18:1 instead of the 22:1 it has. (they wondered why it was blowing headgaskets lol)

This would making starting it much easier. You'd gain a low end torque and highend horsepower with a lot less stress on the engine. The idea of make power with boost rather than iron. If you make power with boost all you must do is cool it rather than overbuild the engine.

This would also give the engine about 400 - 800 rpm more powerband. (maybe, the stoke on these are a mess, with a better turbo you would shortin' up the stroke for better rpm range.

After my current projects in brakes lol, my love with engines is where i like to be, maybe i can find an engine to try these tests on the bench see what works etc...

I am as big of a fan of this engine as anybody - this is a quote from an offical Army monograph of logistics in Vietnam (Library of Congress Catalog Card Number: 72-600389), so don't argue with ME about what it says.

The author of this monograph, Lieutenant General Joseph M. Heiser, Jr., had been engaged in planning and directing logistical support to the U.S. Army soldier, other U.S. Services, and the Armed Forces of Allied Nations since his commissioning as an officer in the Ordnance Corps in 1943. Having served in the Southern Base Sector Command of the European Theater of Operations from 1943 to 1945, he became a staff officer of the Office of the Chief of Ordnance. He later served as the Executive Officer of the Ordnance School and Division Ordnance Officer, 7th Infantry Division, Korea. He was designated Commanding General, U.S. Communications Zone Europe in 1965. He then became, successively, Assistant Deputy Chief of Staff Logistics (Supply and Maintenance), Headquarters, Department of the Army, Commanding General of the 1st Logistical Command, Vietnam, and Deputy Chief of Staff for Logistics of the U.S. Army



A minor typo in the original document - "LD 427" should be LDS-427.

Best wishes,
David Doyle

"Service Support in Vietnam:
Transportation and Maintenance

Though not a maintenance fault, failures of multifuel engines created the requirement for a major off-shore maintenance effort and a sizeable supply problem. In January 1967, more than 300 5-ton trucks were deadlined in Vietnam because of inoperative multifuel engines (a similar condition existed for 2½-ton trucks) due to cracked blocks, blown head gaskets, valve stems and connecting rods. A study indicated that many failures occurred between 9,000 and 10,000 miles and that the units hardest hit were the line haul transportation units whose engines were subjected to continuous use (2,000 miles per month in Vietnam). The prospect for improvement at this point was negligible because of the lack of repair parts and overhaul capacity. Multifuel engines powered both 2½- and 5-ton trucks. A similar condition also existed in Thailand. The annual engine replacement rate of 6 per 100 vehicles per year increased to a rate of one engine per vehicle per year.
By the summer of 1967, an airlift program, Red Ball Express was put into effect in an attempt to alleviate the shortage of engines and repair parts. The Red Ball Express was designed to be used in lieu of normal procedures exclusively to expedite repair parts to remove equipment from deadline status. Reserved and predictable airlift was made available for this purpose. The seriousness of the situation led to a multifuel engine conference on 28 August 1967. The conference resulted in several recommendations, the most significant of which was that three multifuel engines, LD 427, LD 465, and LDS 465, were to be placed under Closed Loop Support management because of the inability of units in the field to cope with the maintenance problem. A further recommendation was made that return to the Continental U.S. be authorized for vehicles that could not be supported with multifuel repair parts or replacement engine assemblies. Because a large percentage of the producers' production capacity was consumed in end items assembly, some repair parts and new replacement engine assemblies were not readily available. Department of the Army approved the recommendations of the conference and directed that necessary retrograde, overhaul, and shipping operations be initiated immediately.
Although the conference had focused attention on the supply aspect and premature failure of engines, significant intangibles remained unsolved, including proper operation of vehicles and user maintenance. Because of the characteristic difference of the multifuel engine from the standard internal combustion engine, periodic maintenance and specific mandatory operational procedures differed sharply from procedures used with other vehicles and required closer attention. Simply put, despite years of testing effort, the multifuel engine did not possess the ruggedness and tolerance to withstand the abuses inherent in field operations."

 

[Neosin]

If you think 500,000 miles is cool, check out the guy over at http://powerstrokehelp.com

The old 7.3L powerstroke is the best of the best. He has well over 800,000 miles on this powerstroke. Taking care of the engine is key! My 7.3L powerstroke ford excursion has 130,000 miles and runs like it's new

There have been some very good posts on this topic. While some swear by the multi fuel some swear at it. I personally believe it is quite remarkable for the time it was designed in. First off the multi fuel engine is nothing more than a long stoke diesel engine that can operate on other fuels. The important thing to remember is that it is a long stroke diesel. Most long stoke diesel engines redline around 2100-2200 rpm. Long stoke engines do not like being over revved. It only takes once and the life of the engine is reduced. It may not happen today, maybe never, but that’s what causes more engine failures in the multi fuel than anything else. The multi fuel engine in most of these trucks redlines at 2600 rpm. I think it is a testament that the engines hold together as well as they do. With that said, I believe that if one were to place a new multi fuel engine in service, change the oil every 3000 miles and never once allow it to go over 2600 rpm the engine would run at least a half a millions miles. However if it is over revved at all it will have a shorted life.

 

[OD_Coyote]

If you think 500,000 miles is cool, check out the guy over at http://powerstrokehelp.com

The old 7.3L powerstroke is the best of the best. He has well over 800,000 miles on this powerstroke. Taking care of the engine is key! My 7.3L powerstroke ford excursion has 130,000 miles and runs like it's new

Even better than the 800,000 mile 7.3L Navistar is the Cummins with 1,000,000 miles.

http://www.dodgetalk.com/forums/archive/index.php/t-18020.html

 

[Recovry4x4]

opcorn:opcorn:

 

[Rolling_Eudaimonia]

I am as big of a fan of this engine as anybody - this is a quote from an offical Army monograph of logistics in Vietnam (Library of Congress Catalog Card Number: 72-600389), so don't argue with ME about what it says.

The author of this monograph, Lieutenant General Joseph M. Heiser, Jr., had been engaged in planning and directing logistical support to the U.S. Army soldier, other U.S. Services, and the Armed Forces of Allied Nations since his commissioning as an officer in the Ordnance Corps in 1943. Having served in the Southern Base Sector Command of the European Theater of Operations from 1943 to 1945, he became a staff officer of the Office of the Chief of Ordnance. He later served as the Executive Officer of the Ordnance School and Division Ordnance Officer, 7th Infantry Division, Korea. He was designated Commanding General, U.S. Communications Zone Europe in 1965. He then became, successively, Assistant Deputy Chief of Staff Logistics (Supply and Maintenance), Headquarters, Department of the Army, Commanding General of the 1st Logistical Command, Vietnam, and Deputy Chief of Staff for Logistics of the U.S. Army



A minor typo in the original document - "LD 427" should be LDS-427.

Best wishes,
David Doyle

"Service Support in Vietnam:
Transportation and Maintenance

Though not a maintenance fault, failures of multifuel engines created the requirement for a major off-shore maintenance effort and a sizeable supply problem. In January 1967, more than 300 5-ton trucks were deadlined in Vietnam because of inoperative multifuel engines (a similar condition existed for 2½-ton trucks) due to cracked blocks, blown head gaskets, valve stems and connecting rods. A study indicated that many failures occurred between 9,000 and 10,000 miles and that the units hardest hit were the line haul transportation units whose engines were subjected to continuous use (2,000 miles per month in Vietnam). The prospect for improvement at this point was negligible because of the lack of repair parts and overhaul capacity. Multifuel engines powered both 2½- and 5-ton trucks. A similar condition also existed in Thailand. The annual engine replacement rate of 6 per 100 vehicles per year increased to a rate of one engine per vehicle per year.
By the summer of 1967, an airlift program, Red Ball Express was put into effect in an attempt to alleviate the shortage of engines and repair parts. The Red Ball Express was designed to be used in lieu of normal procedures exclusively to expedite repair parts to remove equipment from deadline status. Reserved and predictable airlift was made available for this purpose. The seriousness of the situation led to a multifuel engine conference on 28 August 1967. The conference resulted in several recommendations, the most significant of which was that three multifuel engines, LD 427, LD 465, and LDS 465, were to be placed under Closed Loop Support management because of the inability of units in the field to cope with the maintenance problem. A further recommendation was made that return to the Continental U.S. be authorized for vehicles that could not be supported with multifuel repair parts or replacement engine assemblies. Because a large percentage of the producers' production capacity was consumed in end items assembly, some repair parts and new replacement engine assemblies were not readily available. Department of the Army approved the recommendations of the conference and directed that necessary retrograde, overhaul, and shipping operations be initiated immediately.
Although the conference had focused attention on the supply aspect and premature failure of engines, significant intangibles remained unsolved, including proper operation of vehicles and user maintenance. Because of the characteristic difference of the multifuel engine from the standard internal combustion engine, periodic maintenance and specific mandatory operational procedures differed sharply from procedures used with other vehicles and required closer attention. Simply put, despite years of testing effort, the multifuel engine did not possess the ruggedness and tolerance to withstand the abuses inherent in field operations."

What else does the report say? Did they compare the wear of the LDT series engines in the Temperate zones against these tropical problems? I mean that would be interesting to see if perhaps the problems of Vietnam and Thailand were environmental in nature or perhaps operator error given the climate? And what is a standard internal combustion engine? Does that mean a diesel engine setup to run only diesel, or a spark ignition engine? What do they mean by field operations and ruggedness? These terms are all ambiguous and seem to say little about the conditions that the engine faced. Perhaps people were driving the engine with too little coolant in 90+ degree temps at 2600rpm... That's surely going to decrease engine life as the oil brakes down and engine starts to increase it's wear due to friction. It seems to me that US Army read this report and pulled out this handy dandy manual to try and combat some of the problems they were facing.. see attached file.

But really I would love to just see the whole report and see their findings. It just seems that the section you've printed out lacks a baseline comparison.

 

[DDoyle]

There is not a baseline comparision - as I see it, they determined the average life of the engine was 9-10000 miles. To paraphrase a recent famous quote "You go to war with the equipment you have". These folks were evaluating how their equipment was holding up - not how equipment they might have had might have held up. As the title says, the title is "Service Support in Vietnam" - so operations in non tropical conditions would not be relavent to this topic.

After a quick Google search, I see that the entire historical monograph is now available on line at: http://www.history.army.mil/books/Vietnam/logistic/index.htm - or you can buy a copy from the Government Printing Office.

Best wishes,
David Doyle

 

[SasquatchSanta]

When the convoys used to go through Saigon they would always run at the highest RPM, in the lowest gear possible to maintain their desired/required speed. The object was to make a lot of noise and be as imtimidating as possible in an attempt to keep both Charlie and civilians from daring to get in the way. Sometimes you could tell when the guys in the convoys had recently been fussed with. There was a lot of RPM and noise. The message was "We're Bad --- Don't Even Think About It!"

 

[Rolling_Eudaimonia]

There is not a baseline comparision - as I see it, they determined the average life of the engine was 9-10000 miles. To paraphrase a recent famous quote "You go to war with the equipment you have". These folks were evaluating how their equipment was holding up - not how equipment they might have had might have held up. As the title says, the title is "Service Support in Vietnam" - so operations in non tropical conditions would not be relavent to this topic.

After a quick Google search, I see that the entire historical monograph is now available on line at: http://www.history.army.mil/books/Vietnam/logistic/index.htm - or you can buy a copy from the Government Printing Office.

Best wishes,
David Doyle

Yes, it would be very relevant because you need to develop a baseline for proper analysis... How you do it, could be to compare the wear of the temperate zone operators against the tropical climate zones so one could develop a proper service regime.

 

[Barrman]

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.

 

[hoopsoft]

Mine shows 71,000.. I guess I need to give the numbers to the guru so he can find out the history of mine.

 

[DDoyle]

Yes, it would be very relevant because you need to develop a baseline for proper analysis... How you do it, could be to compare the wear of the temperate zone operators against the tropical climate zones so one could develop a proper service regime.

Your goal is evidently not the same as that of those who commissioned the army monograph. You want to know why - as you can see if you read the monograph at the link posted (I have), this monograph does not address why, nor is it intended to - it simply says what happened. Which is exactly what it was intended to do. It is not intended to an engineering analysis of any system used in Vietnam.

Much like saying on December 7, 1941 the Japanese sank the battleship Arizona. That is what happened...just like these engines lasted 9-10000 miles in Vietnam. Why the Japanese attacked Pearl Harbor doesn't alter the fact the battleship sank.

Regards,
David

 

[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.

 

[Neosin]

Man I love diesel engines. I've never owned a dodge truck but i love the engine. I've owned newer chevy diesels duramax 6.6 LLY engine and that engine was a beast, however the iron in a 7.3L durmax is just awesome. it's only a 16 valve engine which means rebuild costs are half that of the 6.0 powerstroke or duramax (isuzu). If I ever have to replace my powerstroke in my excursion i might go to a cummins engine for it. My excursion now get s 24mpg at 70 on the freeway... And there is more i can do to it... havn't even done the ram air mod yet...

Point is, i love diesel engines. It's one of the reasons I bought a multifuel deuce. Love the wisseler turbo and something about a big inline 6 diesel...

Any of your good diesel engines you should be able to get 1 - 2m miles out of by just keeping the oil fresh and filters clean.

Even better than the 800,000 mile 7.3L Navistar is the Cummins with 1,000,000 miles.

http://www.dodgetalk.com/forums/archive/index.php/t-18020.html

 

[1stDeuce]

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

 

[Neosin]

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.

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.