running gasoline/diesel mix in an emergency

[KnotYet]

Sulfur is not, nor ever was a lubricant. People became confused when they learned that ULSD had less lubricity. The assumption was made, and it has become lore, that the sulfur was providing the lubrication.

The reality is that the PROCESS of removing sulfur also removes the components of diesel that provided lubricity.

There are many articles available that explain the process and result. Here is one: https://axi-international.com/ultra-low-sulfur-diesel-ulsd/

Pedantism aside, while my statement may read as though sulfur is the now reduced
lubricant in diesel, I didn't say that. I suppose I should have said something like:

'Sulfur is contained in the long-chain molecules that the hydrotreating reduces
thus reducing modern diesel fuel's lubricity.'

 

[OldDan1943]

Neighbor, farmer, was proud of restoring a couple of his 'hit and miss' tractors.
About 2-3 ft fly wheel to spin by hand. Started it on gasoline and when the engine was warm, twist the petcock and presto, running on diesel. Engines were all cast iron.
We lived in Michigan and he needed something to do in the winter. Last I heard, he was still around at 109 years old.

 

[Slowmo]

As a former fuels & lubricants engineer do NOT ever, repeat ever, add gasoline to diesel. The problem is that it creates a potentially explosive vapor mixture in the fuel tank. Diesel alone has too low a vapor pressure to have a combustible mixture in the vapor space in the tank. Gasoline alone has a sufficiently high vapor pressure that the vapors in the tank are not combustible - there is insufficient oxygen. A mix of the fuels creates a mixture where the are gasoline vapors AND oxygen within the range of combustion, i.e. explosion. I've seen comments about adding things like ATF or other oils to the fuel. Don't do this either. Not because of fire but because the additives in the lubricants will foul your injectors.

 

[johnrupp]

this is copied directly from that article:

"when the few ag diesels in use were started by gasoline pony engines or with compressed air."

The MD diesel was simply a model M, same features and options, but with International’s newly upgraded gas-start diesel. While the MD engine was of a similar design to the WD-40, it had five rather than three main bearings and displaced 248 cubic inches versus 460. They both made approximately the same belt horsepower, which illustrated the improvements in diesel technology. Like the older IH diesel, the MD was two engines in one. For starting and warmup, it operated on gasoline but was switched over to diesel operation. That was innovative technology in the day, when the few ag diesels in use were started by gasoline pony engines or with compressed air.

To start the engine, the driver operated a compression release lever opening a third valve in the cylinder head, called the starting valve, uncovering a separate combustion chamber that both increased the combustion chamber size and exposed the spark plug. With the starting valve open, the engine had a 6.75:1 CR and used a tiny, fixed-orifice carburetor designed only to run the engine at a fast idle. At the same time, the control disengaged the distributor ground, opened a fuel valve in the carb and a butterfly valve that connected the gas cycle combustion chamber to inlet air and closed the diesel intake.


The diesel side of the 248-cid gas-start four-cylinder diesel shows the IH injection pump and dual fuel filters. They took clean fuel seriously, with a water separator (glass bowl) followed by a primary and fine secondary filters. The injection pump has it’s own fuel pressure gauge that warns the operator when the filters are becoming restrictive.

The gas side (cough, gag!) shows the spark plugs, distributor and tiny carburetor. There was no driver-controlled throttle on the gas side. The carb was big enough to run the engine at about 800 rpm for warmup. When warmed up, you switched the engine over to diesel mode.
The engine was cranked over using a 12-volt starter and would idle at 600-800 rpm. This was enough to warm the engine up as long as needed for diesel combustion to be possible. Though there was a choke, idle speed was not controllable by the driver. After warming up the engine for one to three minutes, the compression release lever was pulled back briskly. That closed the starting valve, shut off the gas to the carb, grounded the distributor (killing the spark), closed the gas intake manifold and enabled the diesel injection pump. The engine then began running on diesel with barely a hiccup. For the shutdown, you switched back to gas and shut off the engine with the ignition switch, making it ready for the next start.

Keith,

I don’t quite understand your post. There’s no doubt many early ag and industrial diesels used pony motors or compressed air to start. The CAT RD6 is a good example.

What made these International diesels unique was they started on gas then you switched to diesel after warmup. The three paragraphs after the one you posted goes into detail. If you’re interested there’s a few good utube videos on them.

Hope your weathers warmer than mine.

John

 

[Island Cessna]

What made these International diesels unique was they started on gas then you switched to diesel after warmup.

I ran an International TD6 dozer that had this type of engine. It was a complicated, obsolete oddity in the 1960’s, but ran well.

Worked on several Cat products of similar age with pony motors. They were more complex and expensive to build, but bullet proof reliable. The pony motor usually had a suitable sized (ie small) electric starter but could be rope started if needed. You could crank the diesel for as long as you had gasoline available. The pony motor exhaust heated the diesel intake air.

I worked on pony motor equipped No 12 Motor Grader, D6, D8 and D9 crawlers. They were the gold standard for reliable cold weather starting.

 

[OldDan1943]

Traditionally, diesels on submarine were/are air start.

 

[TowLou]

Not really an answer, but just some info. Gas and oil pipelines that transport fuels to tank farms around the US, push any intermix (gas/diesel combo) into the gas tanks and keep the diesel tanks pure as possible. Gas engines can tolerate impure fuels better than diesel in general, and they go to great effort (and fuel oil losses), to keep the product clean and pure.

Additional info, such mix is called transmix atleast from the fuel racks I filled up at. It was trucked away to be refined.