glow plugs on deuce?

[m16ty]

Why do diesels not have spark plugs

Some do . The first diesels in IH tractors started on gas and switched over to diesel. On one side of the engine they had a carb and spark plugs. The other side had an IP and injectors.

 

[greenjeepster]

Yes had a farmall 400 that was gas over diesel. That isn't really a diesel, but it was a neat old tractor.

 

[Keith_J]

Why do diesels not have spark plugs

The Diesel cycle relies on autoignition. At time of injection, the aerosol mist ignites almost instantly. If the delay is more than the total duration of the injection (low power), you get that diesel "knock". The delay is based on many factors, mostly due to the characteristic called cetane index. Cetane, a linear hydrocarbon with 16 carbons and 34 hydrogens, has the least ignition delay and is used as a standard.

Unlike a gasoline engine where the fuel must resist autoignition because all the fuel is present at time of ignition, diesels have a span of injection after primary ignition. This is why they can use fuels which autoignite.

 

[m16ty]

Yes had a farmall 400 that was gas over diesel. That isn't really a diesel, but it was a neat old tractor.

I'm curious as to why you say it isn't really a diesel? When switched to "diesel mode" it works like any other diesel. IH called them diesels.

Back in those days almost all diesels were hard to start. That's why IH went with the design they did and why the Cat and JD diesels started with gas pony motors.

 

[glcaines]

A little off-topic, but I once saw a Japanese military three-cylinder diesel GenSet from WWII that started with explosive cartridges like a shotgun shell. There was a separate chamber with a piston that rotated the crankshaft about one revolution. This was also a direct injected diesel and did not have glow plugs.

 

[greenjeepster]

The IH Farmall diesel was an attempt to enter the diesel market without completely retooling. They were set up to produce gas powered tractors so they essentially made a gasoline engine that ran on diesel. It did not have the compression that a diesel has. You could crank it all day long trying to start on diesel and it would not start. It really isn't a compression ignition engine; starting it on gasoline heated the engine up to the combustion point of diesel oil so that it could ignite at a lower compression. Once running on diesel you manually turn the compression stroke up. Bare bones it was a Farmall M gasoline engine with some heavy modification.