Gas, Kerosene, Diesel Fuel Differences

[GlueGuy]

Somebody else correct me if I'm wrong, but my understanding of diesel fuel is that it would be a relatively "low" octane rating (maybe somewhere around 60 or 70 octane?).

Reason I believe this is a number of years ago, Chevron accidentally contaminated some 100LL avgas in our area with jet fuel (similar to kerosene). Net result was that instead of getting 100 octane fuel, we had something that was below 80 octane. Caused pre-detonation for everyone that had an engine built for 100 octane.

Result was that about 1300 aircraft in our area had damaged engines (mine too). Things like bent valves, and other internal damage not easily repaired.

Bad news was my airplane was one of those that had gotten damaged. /w3tcompact/icons/frown.gif. Good news was that Chevron ponied up the cost to replace the engine /w3tcompact/icons/smile.gif.

The GlueGuy

 

[skent]

Whats weard here is one of my old tractors had a "low cost fuel" option. The tractor had two gas tanks, one for gasoline (two gallons) and one for kerosene (17 gallons). The book is VERY specific that the engine must be started and fully warmed up on gasoline, then the fuel valve would get flipped over to the main tank and you would operate on kerosene. BUT you HAD to remember to switch back to the gasoline fuel BEFORE you shut off the engine or else you would have real problems trying to start on Kero.

I guess the main thing here is I'm talking about a 250 Cubic inch engine with a 5:1 compression ratio, HP rating of 33, and redline of 1325 RPM.

 

[GlueGuy]

I've never seen anything like that. However, I did drive a truck in the military that was a "multi-fueler". You could alledgedly run "any" kind of fuel in it. We mostly just put diesel in them, but occasionally would put in gas or kerosene.

The GlueGuy

 

[Harv]

<font color=blue>Harv, You may have it reversed.</font color=blue>

Wouldn't be the first time. /w3tcompact/icons/crazy.gif

I appreciate your thoughts, Gerard, but my comment was made back in early January, so I believe the statute of limitations is up. /w3tcompact/icons/wink.gif

 

[TraderMark]

skent...
I worked For Case for a number of years and one day a guy brought an irrigation pump in that was powered by an old Case engine. At first glance I thought it was a gas burner, but once I started working on it, I saw it had two tanks for fuel. I got curious and went to the parts manual and found that it too, cranked on gas and then ran on kerosene once it warmed up. First time I'd ever seen an engine run on kerosene through a carberator. /w3tcompact/icons/laugh.gif

BTW.... that old engine was old enough that it had poured babbit bearings. I really enjoyed rebuilding that unit.

 

[DavidH]

skent: I watch "classic tractors" on my satellite dish, and a lot of the old John Deere tractors from the 1930's used a gas engine that was called a pony engine. You would start the pony engine and this engine would then be used to start the diesel engine. After the diesel was started you shut off the pony engine.

DaveH

 

[TraderMark]

DavidH
Caterpillar used pony engines a lot too. My dad had several old D8's from the late 40's early 50's that used 2cyl pony engines to turn the big 6 cyl diesel and to heat it as well. The exhaust from the pony engine went through the intake on the big engine to warm it up, with the compression released of course.... then once it was warm, throw the lever to restore compression, throw the lever to engage the clutch on the pony motor and...... puttt....putttt......PUTTTTTT.... that old 6 cyl would fire off. /w3tcompact/icons/laugh.gif/w3tcompact/icons/laugh.gif/w3tcompact/icons/laugh.gif

Max RPM on that old baby was about 1200rpms but man was it strong.

 

[Anonymous Poster]

 

[cowboydoc]

John,
Here's a question for you. I went down to Mississippi to get some mares this weekend and up here in Iowa, Illinois, diesel is more expensive than gasoline. When you get down to Missouri, Arkansas, Tenn., and Miss. then diesel is less expensive than gasoline. Winterblend in all states, truck stops in all states. I asked them why and noone knew the answer. We're talking big differences too.

 

[MJB]

Running gas powered tractors on kerosene was extremely common from the very earliest gas tractor engines (around 1900) up until the early 1950s. At the time the cost of kerosene was much lower than gas. In order to run kerosene the engine had to have a fairly low compression ratio and a special heater box on the intake manifold to keep the air/fuel mixture warm. These engines were almost always overhead valve, even though flatheads were much more common in car engines. Old tractors usually had shutters on the radiator also to help them warm up faster. Kerosene has a lower energy density than gasoline so it delivered less power than gas, and was very difficult to start on, but the much lower cost made it attractive. The owners manual for my 1952 Case DC-4 has a complete set of instructions on how to start and operate a tractor with the "low cost fuel option". Now that kerosene costs more than gasoline there isn't much point anymore.