1920 Thermoil Model U 6hp diesel

[n8in8or]

I attended the local tractor show this afternoon and stumbled on a pretty cool engine. It was a little stationary diesel engine built in 1920! The owner had some literature for the engine on display and I took a picture of it.


I thought it was pretty cool how familiar the combustion chamber looked even 96 years ago. One main difference was that the fuel wasn't injected in. I spoke to the owner for quite a few minutes and he was also the one that restored the engine. He told me that rather than injection, a valve opened when the piston was on the downstroke and it would allow the fuel to be drawn in, then it would close to build pressure on the chamber which of course causes combustion. He said it can be quite finicky to start, especially when cold. When it is being cranky, he has a Honda 5hp gas engine mounted on a hand-held rig to turn the engine over instead of cranking it over by hand. I got to watch him restart the engine because he had to shut it down for regreasing (which he does every 1.5 hours). It actually didn't start too badly for being turned over by hand, but it hadn't cooled off too much in the time he repacked all the grease cups (maybe 5 minutes or a little more?). Another interesting thing about the engine is that of course it was marketed to run on just about any fuel but gasoline, but in order to do so you had to adjust the compression ratio......yes, the compression ratio! You did this by adding or removing shims in the 3 piece connecting rod! I wish I had taken a picture of the rod to illustrate this. He said the factory shipped the engine with a .012" shim and taking that out alone made a big difference depending on the fuel and conditions. It also affected timing as well. It was so cool talking to such a knowledgable man regarding such a unique engine.

Here's a quick video of it running. Enjoy.

 

[THEFERMANATOR]

The ricardo bowl design has been around for a long time, but not just in diesels, many flathrad gas engines also used it. The difference was they built it into the head instead of the piston top.

 

[Will L.]

Also the metulurgy changes helped improvements to the design. Ricardo was one smart puppy.

 

[n8in8or]

That's why I love going to tractor shows - everything is so much more out in the open on agricultural stuff, so you can see what people were trying when people will still trying to figure out what worked and what didn't. Plus at the shows you're more likely to see the stuff running and even working than you are at a car show. More of the tractor show guys actually work on there stuff too rather than just buying someone else's work. Anyway, it's cool to see what looks familiar and what doesn't.... There were some really smart dudes working on ideas back then.

 

[schiker]

Cool! Thanks for sharing. Yeah, I like seeing that stuff too. Hit and miss engines show up sometimes or other big 1 cylinder stuff at different events. I saw an old semi mobile cotton gin once powered by a 1 maybe 2 cylinder something but missed it processing the cotton. It was mounted on about a 16 foot flat bed trailer. Just neat to look at though. You just have to respect a guy that would sit on and operate some of that old farm equipment. One bad mistake and you were a gonner.

Yeah, ag type shows I would say are a bit more about the mechanisms than just looks. IMO a nice clean tractor is prettier and holds my attention more than a sports cars anyway. Another neat thing I saw once was if I remember right a John Deere tractor that was cut up to show side sections in different places by a trade school to show the internal shafts and bearings and passages etc . It had holes in the engine, transmission and rear axle etc .

 

[n8in8or]

Cool! Thanks for sharing. Yeah, I like seeing that stuff too. Hit and miss engines show up sometimes or other big 1 cylinder stuff at different events. I saw an old semi mobile cotton gin once powered by a 1 maybe 2 cylinder something but missed it processing the cotton. It was mounted on about a 16 foot flat bed trailer. Just neat to look at though. You just have to respect a guy that would sit on and operate some of that old farm equipment. One bad mistake and you were a gonner.

Yeah, ag type shows I would say are a bit more about the mechanisms than just looks. IMO a nice clean tractor is prettier and holds my attention more than a sports cars anyway. Another neat thing I saw once was if I remember right a John Deere tractor that was cut up to show side sections in different places by a trade school to show the internal shafts and bearings and passages etc . It had holes in the engine, transmission and rear axle etc .

That cotton gin would have been cool to see running. Too often the hit n miss engines are just sitting there putting along and not actually doing any work. I like to see and hear stuff actually working.

There's a show in Indiana that has a bunch of Amishmen and their Oil Pull tractors in attendence. They usually hook 3 or 4 Oil Pulls to a 20 or so bottom plow to watch them work. Pretty cool seeing them all work in tandem. Oh and the plow isn't hydraulic lift.....there's a platform on it where men stand on it and raise and lower the plow manually with levers. Good stuff indeed.

 

[ak diesel driver]

The cool thing about hit and miss engines idling is actually hearing how many times it turns over between firing. Pow chugga,chugga,chugga,chugga,pow,chugga,........

 

[NVW]

I think you got one too many chugga's in there Les
Grain elevators used them to run the grain legs.

 

[THEFERMANATOR]

The cool thing about hit and miss engines idling is actually hearing how many times it turns over between firing. Pow chugga,chugga,chugga,chugga,pow,chugga,........

Or if some fuel collects in the exhaust, you get a different pow mixxed in. I always set them to where you could just about put your hand in the flywherl before it would take off again. Used to have an old one, one of the most reliable engines I ever had. It had the crudest setup you ever seen. The carb was nothing more than a galvanized pipe cape drilled with holes, and a 1/4" fuel line run through one of them and an adjuster in the line.