Duece and a half

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I've seen that diesel military vehicles, like the old deuce and a half, can run on old motor oil. What makes them able to do this where our diesels can't?
 
Emissions. Even the mid-90s Dodge Cummins could use fry oil, used motor oil, heating oil, whatever you cared to pour into it (filtered for chunks of course)
 
Diesels will run on pretty much any kind of oil, the reasons I think are military vehicles still run on it is quite simply they are engineered that way.

For example the 1.9 XUD engine as fitted to many Citreons and Peugeots could run on pretty much anything, engine oil, used engine oil, used cooking oil(filtered) and virgin cooking oil not forgetting biodiesel.

Why could it do this?

Because the Bosch diesel pump was not reliant on the fuel for lubrication, but relied on the engine oil.

Any diesel will run on used oil, bio or cooking oil, just that due to lack of lubrication or simply being too thick for the pump to flow when cold the lump would suffer. Hence why people have twin tank systems that start on normal diesel and then have a seperate tank for cooking oil either used or virgin, I think they are heated aswell.

If you check I think you will find the diesel pumps are also lubricated by the engine oil.
 
Check out the CP4 injector pump that the Duramax, PSD and VW TDI use. The failure rates are insanely high. This is with "filtered diesel" it costs the Fords 12k + for a repair of a CP4. When it goes it TRASHES the fuel system. tighter tolerances maybe combined with SUPER poor build quality of the fuel systems for the NA market.
Bosh has admitted they never built the CP4 to run on NA diesel fuel. why the heck would you let a company fit it to a vehicle being sold here then????
The 6.9/7.3 IDI and the 12V would run on darn near anything.
Emissions SUCKs..
if a 6.0L gets 20mpg and a 6.4 gets 10mpg WHILE producing half the emissions and making it so friggen complex. WHY THE HECK are they waisting the time.
They are cutting costs to increase profit margins at the expense of the owners. Heck, I'm looking at a Dodge just for the stick shift and CP3
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and Dodge's build quality is horrific
 
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As a broad generalisation, if you have an in-line pump, like so many disels used to have, they can run on nearly anything that fits in the tank. Bosch rebuild procedure was to fill IP with SAE 30 after a rebuild.

A rotary pump, without viscosity control (heating) is simply asking for trouble, and even with viscosity control is still asking for trouble.
 
So let's say that I'm looking for one of these older diesels. Where would U steer me? 5.9 Cummins? What yr? What else could I do to it to make sure it would work on the ocasional dose of old, filtered engine oil, etc?
 
You would want the P-pump Cummins, or the inline IP used on older Mercedes IDI diesels, like my '82 300D. Contrary to what some say, I would be hesitant to run any old oil in a Stanadyne rotary (Ford/IH 6.9/7.3 IDI, GM 6.2/early 6.5) or Bosch VE (early Cummins Ram) or VP pump-they can still be easily damaged by water or junk in the fuel. Don't forget, fuel dilution of your oil or even jamming of piston rings can result from non-diesel oil that doesn't completely burn in the combustion chamber-that's why biodiesel is processed.
 
Originally Posted By: 05Blazer
Kuato,

What cummins engines do you speak of and what years? ARe you referring to 94-98 5.9L 12Valves?


I knew a guy that had a '93 Cummins Dodge. He had put used oil and vegetable oil in it and not had an issue, except I think lower mpg with the veggie oil.

Check this: https://www.youtube.com/watch?v=TAxw2HG70g4

I also knew a guy that ran his 80s MB diesel on jet fuel. (he was a mechanic and got the fuel for free.)
 
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you can run MoGas in a Duece and a Half.

You had to add motor oil in to lube the injector pump. I forgot the ratio. It was a fairly significant amount.

Kerosene, JP8....didn't matter. I'm sure we could have used the grease from the fryers at the Mess Hall (DFAC for you young troopers). It probably wouldn't have run very well but they didn't run that great anyway.
 
Originally Posted By: Spazdog
you can run MoGas in a Duece and a Half.

You had to add motor oil in to lube the injector pump. I forgot the ratio. It was a fairly significant amount.

Kerosene, JP8....didn't matter. I'm sure we could have used the grease from the fryers at the Mess Hall (DFAC for you young troopers). It probably wouldn't have run very well but they didn't run that great anyway.


Obviously when somebody's waiting for ammo, the emission profile of the vehicle carrying it is secondary.
 
There were some trucks, Mack I think, that used to cycle engine oil into the fuel tank and replenish the sump from a remote tank...a continuous oil change. The Mitsubishi 4M40 has a gear driven rotary pump, the lift pump is in the front of a VE pump, and instead of diesel leaking into the sump as you'd expect, the pump sucks engine oil into the fuel system. You know you have this problem when the fuel filter is black from engine oil. There are starting problems because a small amount of fuel drains from the lift pump, but the engine runs fine on black fuel.
 
when i was in the USA Army in the mid 70s. our old deuce and a half was a mulita-fuel engine, would run on, all diesel fuel, a mix of diesel/gas, or gasoline stright. but my 5 ton wrecker was a straight diesel.
 
I was a 63B Light motor vehicle mechanic in the Army. The engine in the olde 2 1/2 truck was a MAN design built under license by engine companies such as Continental, Hercules, and Mack. The fuel pump has a fuel-density compensator (FDC) on the end of the pump where the fuel line is fastened. Basically, the FDC "weighs" the fuel coming in and adjusts the injection timing. The operating theory is that denser fuel will burn more slowly, so the injection timing is longer to get through the injectors. If you use gasoline or similar (and it WOULD burn alcohol, paint thinner, solvents, literally anything that would take fire from a match), mix 1 QT of SAE 10 oil to 25 gallons to lubricate the pump.
FWIW, all of the land forces are now on one fuel to make supply simpler; and I believe it's JP8.
 
The engines in the olde Truck, 2 1/2 ton, 6X6, M-48, were compression-ignition engines designed by M.A.N. (Machinen fabrik von Augusburg und Nuernberg) built under license for the Army by Mack, Continental, White, and Hercules. The pump was a Bosch single piston distributor type, where the fuel lines from the pump to the injectors looked for all the world like reallly long spark plug cables. As the fuel entered the pump, it went through the Fuel Density Compensator. The density of the fuel would cause an adjustment of the quantity of the fuel injected, and change the injection timing. The theory was that the denser the fuel, the more energy. The denser the fuel, the more time it would take to burn.

IIRC, the Technical Manual called for 1 Qt. SAE 10 oil per 10 gallons of gasoline, just to lube the pump. It would get much lower mileage on gas, but it would go. I believe that even with a turbo, the output was 130 hp. But then the Army only planned on it going 35 mph in line-haul style operations.
 
The old ones would run on just about anything because the injection systems were a lot more robust and simple. The old injectors were just a poppet valve with a nozzle on one side, it fired once per compression cycle and didn't need to be too terribly precise in metering fuel. Same with the pumps, they ran at a couple thousand psi at most, The new fuel systems on these trucks are using electronically fired injectors that can fire 4-5 times per cycle and pumps that operate at 30 thousand psi. To do that everything must have very precise tolerances, a change in fuel viscosity or a little debris in the fuel and the whole thing falls apart and parts get damaged.
 
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