Have you ever heard of a propane tractor? Take a look at the inner workings of one North Dakota man’s Minneapolice-Moline M5 LPG tractor.
I’m one of those people who tends to think that life was better back in the days when things were simpler, but just sometimes I have to admit that modern life, and the internet in particular, has opened doors for me that would otherwise not have existed.
For instance, without the internet, I doubt that I would have found this magazine, and I would certainly not have emailed the editor, Leslie, to ask if I could write some articles in her publication. Without the internet, neither would I have received an email from a reader called Donny Denfeld, who had read one of my articles on British tractors, and had a few questions to ask me about the sort of tractors that we collect here in the U.K.
By the time Donny and I had exchanged a few emails, I had learned that he was himself in possession of quite a substantial collection of vintage tractors, and I also came to understand that American tractor enthusiasts are much the same as British tractor enthusiasts. Whilst these enthusiasts come in a few different guises, I think they are essentially similar the world over.
Yes, tractor enthusiasts vary. There are scrupulously tidy tractor enthusiasts, whose spanners are all pinned to the wall in order of size, and there are messy enthusiasts, with workshops that look like a bomb has gone off in there. There are the types who religiously collect only one brand of tractor, those who only have the one tractor (perhaps a family heirloom tractor) and they have no intention of ever owning another. Then there is the enthusiast who just can’t say “no” to any tractor, especially if it is interesting looking and going cheap. Donny is this kind of tractor enthusiast. Donny’s collection is eclectic and his tastes are governed only by three things: Is the tractor fascinating? Is it a bargain? And, is it possible to get it home?
Cheap at twice the price
The tractor I wish to focus on today is Donny’s 1960 Minneapolis-Moline M5. This tractor ticked all of the boxes for Donny, and it wasn’t only a bargain: It was totally free! This tractor is of particular interest to me because it is powered by LPG, which is something that is almost unheard of here in the U.K.
Donny is a mechanic who works for a heavy equipment company in the North Dakota oilfields. One day his firm happened to be rebuilding a parking lot for a local sandblasting and painting business. While on site, Donny spotted an old tractor parked up next to a swamp. When the owner of the site came over to talk to the workman about his plans, Donny took the opportunity to ask him about the tractor. “Oh that …” the owner said. “If you want to come over on Saturday with a trailer, you can have it.”
This is the kind of offer tractor enthusiasts dream of, so Donny duly turned up on the Saturday morning with a trailer. The owner kindly helped him load the tractor and it followed Donny home. “I reckon it had been standing for around eight years when I acquired it,” he says.
Now a chap can’t be too fussy if he is getting something for nothing, but all the same, no one wants to bring home a bag of trouble. When Donny got the tractor home and began really looking at it, he could only hope that it didn’t have any big problems. It certainly looked pretty good, especially for something that had been standing out for several years. “The rear tires were still in good condition,” he recalls. “One of the front tires was flat, but the hood, the grille and the rear fenders were all in great shape.”
At that point, I was reminded of a couple of differences in how things are in our two countries. First, here in the U.K., we call a hood a “bonnet,” which I suppose seems a quaint and antiquated term for a shaped piece of tin that goes over an engine. The other difference is weather. Here in the U.K., we have a damp, maritime climate. That means our countryside is always beautifully green and lush, but it also means that our machinery rusts big time if it is left outside. I am always amazed how American readers tell of tractors that have been abandoned outside for decades and which haven’t fallen victim to the dreaded rust. Such tales are enough to make a person quite envious, as here so many abandoned wrecks are just too far gone down the line to repair.
Cleanliness and longevity of an LPG engine
Donny was happy to discover that LPG is rather kinder than other fuels. “Propane never really goes bad, so although the tractor had been standing for a number of years the fuel system on the M5 was still in great shape,” he says. “I did have to go through the regulator as the seals were dried, but basically all I had to do to get the tractor running was pull the spark plugs out, give them a clean and re-gap them, then get myself a new battery and the tractor just started up!”
An LPG-powered tractor is somewhat different than a petrol- or diesel-powered tractor. As Donny explains, “In a propane engine the gas is pulled from the tank as a liquid, then as it runs through a regulator (which contains hot engine anti-freeze) it is converted into a gas. This gas is then passed through a mixer which combines air with the LPG vapor, and then the mixture is sent to the cylinders.”
This system has a couple of advantages, one of which is cleanliness and the other is longevity. “LPG-powered engines can last up to four times longer than petrol engines,” Donny says, “because petrol is wet when it is mixed with air, and that will dirty the engine oil, but because LPG is in a vapor form when it enters the combustion system, the engine oil stays nice and clean and you can see that when you change the oil on one of these tractors. Instead of being black, the oil is still honey-colored.”
Pros and cons of a propane tractor
LPG was first utilised in about 1910, when chemist Walter O. Snelling managed to separate the gasses from petroleum, and in the process, he discovered propane. LPG (liquid petroleum gas) was used in 1918 for blowtorches and brazing torches, and a decade later it was used to power a refrigerator and a truck. Soon it began to be used for heating and cooking. In post-World War II America, some 62 percent of households used LPG for cooking and heating their homes.
In the days when there were very few cars on the roads, and even fewer tractors in the fields, fuel economy wasn’t too much of a concern. Initially, only the wealthy owned vehicles, so cost wasn’t a big issue, but as automobiles became more popular, and as farmers expanded their farmland and began to rely more heavily on their tractors, people began to question fuel costs, and they looked around for cheaper alternatives. In a country with a huge acreage of arable land, tractor fuel prices were a concern. LPG was seen as an excellent fuel because it burned cleanly, but most important, it tended to be cheaper than petrol (gasoline), though the cost did depend on one’s proximity to oilfields.
The Minneapolis-Moline company was ahead of its time when, in 1941, they offered an LPG-powered tractor as part of their U range. The U range had several variants, including wide-front, tricycle, high-clearance, industrial, gas-powered and diesel-powered, so the LPG version was another string to this very innovative company’s bow. Minneapolis-Moline could not only claim to have made the world’s first factory-produced LPG-powered tractor, but they could also claim that this tractor innovation provided 10 percent more power, was cheaper to run than other tractors, and its engine had a longer life span than that of other tractors.
Although MM was the first company to offer an LPG tractor, other companies soon followed suit, and during the 1950s and ’60s, LPG became a popular tractor fuel, especially in oil-producing areas. It was, however, never popular in the U.K. as a tractor fuel, so in British collectors’ eyes, Donny’s propane tractor is highly unusual.
As the company that had been producing LPG tractors for the longest period of time, Minneapolis-Moline had the experience to understand exactly what changes had to be made in tractor design to get the best out of LPG. Their LPG tractors featured high-compression heads and large cooling water jackets that helped direct the flow to the hottest parts of the engine. The company ended up producing several different LPG-powered tractors. As is the case with any innovative company, some of their ideas proved more popular than others. On the whole, though, it seems that this was a company that was forward-thinking in many respects, and which was never afraid to experiment with new ideas.
Father and son team up on propane tractor
As a mechanic who works away from home and who often finds it difficult to make the time to fix his own vehicles, Donny wasn’t daunted by the little issues that needed attention on the M5, like the gasket on top of the transmission that needed to be replaced. Donny is blessed to have a father, Larry, who shares his hobby, and Larry is usually more than happy to tend to some of the jobs that Donny doesn’t find time for.
The two tend to share their tractors, and it’s an arrangement that works well. Donny is often in a better position to find interesting tractors, but Larry is often in a better position when it comes to finding the time to get the more time-consuming jobs done. “For instance,” Donny says, “my dad went through both brakes for me, because they weren’t working properly and now, thanks to Dad, they are nice and sensitive.”
Donny also has a good network of friends who look out for parts for him. “A cast iron bracket under the outer radiator screen was broken. The LeSueur swap meet coming up and I wasn’t going to be able to go,” he says, “but a friend went and he managed to get a bracket for me.”
Keeping it original
As it is with most old tractors, the M5 is something of an ongoing project. There are a few little tasks that Donny would like to tend to, in particular the hydraulic system, which isn’t quite as it should be. “It looks like the previous owners must have had an issue with the hydraulic system, as they rigged up their own system by bolting a remote valve to the rear fender,” he says. That doesn’t look too good, so my dad has removed it, and I’m still searching for an original system to replace it with, as I want to put it back to how it should be.”
The old tractor runs nicely, and although it is semi-retired, it still pulls the disk harrow occasionally, and sometimes Donny uses it to cut weeds with, but he never works it very hard. “There aren’t too many of these LPG tractors near my home in Richmond, Minnesota,” he says. “If you head out west toward Montana, or south to Texas, there are more.”
Since I’ve never seen an LPG-powered tractor, I’m curious to know if it feels any different to drive.
“It’s just like any other MM to drive, really,” Donny says. “It’s just that it has a different smell coming out of the exhaust.” FC
Josephine Roberts lives on an old-fashioned smallholding in Snowdonia, North Wales, and has a passion for all things vintage. Email her at josiewales2021@aol.com.
Originally published in the March 2023 issue of Farm Collector.
