What Fuels Are Being Used in Multi- Fuel Engines?

[rsh253]

Hi Folks,

I'm new to this forum and the subject of Deuces in general. I've been reading a lot the postings and have been learning a lot.

I have a question on the fuels folks are using these days in their multi-fuel engines. I assume that diesel is normally used and other fuels as a back-up. With the cost of diesel being more than premium gas, has any body gone to using a mixture of gas & diesel? I use to have a car that would ping on regular, and at fill-ups I'd use 3/4 reg and 1/4 premium and that amount of premium was enough to stop the pinging. I was wondering if mixing gas & diesel could be done in a multi-fuel? Thanks.

-Russ

 

[FMJ]

http://www.steelsoldiers.com/index.php?name=PNphpBB2&file=viewtopic&t=14708&highlight=mixing+fuels

I'm sticking to Diesel with a bit of Marvel Mystery mixed in.

 

[ken]

The problem with gas is there is alot less BTU's per gallon. You milage will suffer alot. Although you will be paying less for gas. You won't go as far on it. Not to mention the loss of lube for the injector pump. You can burn gas. But it's a emergency fuel. Look at the alt fuels section. You will find alot of posts on the fuels we have tried. Everything you can think of have been burn though a multi. Hope this helps.

 

[FreightTrain]

I am using a 50/50 mixture of 87 octane and used motor oil in mine.No problems.I have run 100% 87 before in my truck and no problems and the pyro didn't show any dangers.Maybe a LITTLE lower on power and a MPG less in ecconomy but I didn't buy a MV for fuel mileage.

 

[tmbrwolf]

A lot of the engines were changed over to diesel / JP-8 onlyat the depot, if so do not use gasoline, here's how you can tell if it has been switched:
Look at the return line from the injectors at the injector pump, if it has an elbow instead of a tee it was set up for diesel only. If there is a tee then there is a line that runs behind the injector head to the compensator you can run other fuels. here's the statement from the operator manual about using gasoline:

Commercial gasoline, leaded, low -
lead, or unleaded, when research
octane number (RON) is 89 or below,
or octane number displayed on
retail gasoline pumps in CONUS is
85 or below "emphasis added"

We considered gasoline an emergency fuel only for several reasons:
1) I it may burn the pistons or cause pre-detonation.
2) It shortens the life of the high pressure pump and injector head due to lack of lubrication.
3) May cause the fuel filters to plug.

 

[FreightTrain]

Both of my trucks are converted(I converted one myself) but it it is still safe to use Gasoline in them.All that the above means is the injection pump no longer compensates the amount of fuel per squirt for the thickness of the fuels.It in no way changes the engine from Multifuel to diesel.100% of the multifuel capabilities are in the design of the Injectors,The heads and the pistons.The way the fuel is sprayed into the cylinder and the large pocket in the piston crown plus the swirling motion of the air being sucked/blown into the Cylinder to evaporate the fuel that was dribbled into the fuel cup in the piston.

 

[WillWagner]

I run mine on a diesel/gas mix. Gets 8 to 10 MPG, power os OK..pulls a loaded M105 up Cajon pass at about 30-32 MPH. I have also added mixed 2 stroke gas, some hydraulic oil/diesel/gas mix, kerosene/diesel/gas and NEW ATF/diesel/gas. All seems to run the same, but had a bit more white smoke with the ATF blend.

 

[tmbrwolf]

Freighttrain, I will respectfully disagree with you, Your truck you do with it what you like. If you get a rebuild out of Toole or Red River Army Depot's as I have the sticker on the engine says "Diesel Only" and the sticker further states the compensator must be hooked up to run alternate fuels and they leave you the means to do so on the pump, personally I would only run diesel if it's been converted, I agree that the design of the engine allows the use of other fuels but the compensator on the pump is part of that system, not to mention there are other good reasons not to use gasoline lack of lubricity etc.

 

[swbradley1]

opcorn:

 

[FreightTrain]

The compensator only keeps the horsepower the same for different fuels.That was the only job it was truely designed for.As for the lubricity.Your screwed no matter what way you turn today.Just about all fuel is the same.DRY!The new diesel mandated by the feds(Gee thanks you greenie weenies!!!) is super dry.Almost as dry as Kero.Not to mention much lower in energy.Yea,it is much cleaner but it has contributed to many older mechanically injected diesels to be scrapped since it is distroying pumps and injectors.The deuce will hold up better since the guts are hardened unlike a civilian pump.Although No matter what fuel I use I alway dump in a gallon of Motor oil or a 300 gallon shot of Powerservice for lubricity.

 

[emr]

FreightTrain is correct...on all acounts..Randy

 

[Rebelpride]

K1

I went to a get together with the deuce this past weekend. Right now onroad diesel is $4.239, offroad is $3.759, found kerosene for $3.409, and gas was $3.539. So I poured a gallon of ND 30wt motor in the tank and filled up with Kero. It wasnt any harder to start, the truck seemed to run quieter, didnt smoke as much during warm up, didnt seem to slow down goin up hills as fast, and maintained the same temp. reading as with onroad diesel. The only time that it ran hotter( over 200) was during the hottest part of the day and I was runnin' it at 50mph. It wasnt any harder to start I was thoroughly impressed.

 

[houdel]

RE: K1

Tmbrwolf - I have to respectfully disagree with you. FreightTrain is 100% correct. A multifuel is still a multifuel whether the FDC is bypassed or not. All the FDC (Fuel Density Compensator) does is exactly what the name says - it compensates for the density of the various fuels which may be used.

 

[rsh253]

Thanks for all the input guys. Very helpful. And I managed to generate some controversy on my first post!

 

[yellobronc]

 

[Alredneck]

Yeaa run what ya brung or what ya can get, me runin diesel with UMO and a lil ATF to top er off.

 

[DDoyle]

With respect to the fuel density compensator. Go take a look at the original Multifuel, the LDS-427. There is no fuel density compensator installed anywhere on the engine - and they also smoke a lot when running diesel. That is because the BTU per gallon of diesel is higher than that of gasoline, so on diesel they are running rich.

Never really given much thought, but I suppose that the timing could effect the multifuel capabilities of the engine (perhaps causing predetonation on gas), but IIRC, the trucks with the FDC bypassed have not had their timing changed.

Best wishes,
David

 

[kaiser2help]

I agree with all of you. I am playing outlaw and running #2. I am told with antiques prior to a certain year of MFG you can run alternatives.

 

[Jake0147]

The density compensator only adjusts the fuel rate. The fuel rate adjusts the response to the throttle pedal, and ultimately the overall horsepower and performance of the engine. Isn't the overall performance of the engine part of the specification of the truck? Wouldn't that mean that changing the performance would make the truck "out of spec"? My theory is that this is why the "diesel only" instructions are applied, so as to keep the performance uniform from one truck to the next. Not because it's harmful or detremental in any way to use alternates with the compensator bypassed.

 

[Miamirex]

#2 Diesel best, but must add the lubricants for pump and injector longevity. My question is what do people do in extreme cold. I once read the Germans used a 30% kerosene mixture for the very harsh russian winters, just so they could get their beasts started and prevent total gelling, cherrs.