Minnesota Man Creates a Special Go-Getter
The completed Fairmont/Simplicity tractor showing the flat belt, belt tensioner and jackshaft pulley. Also shown is the clutch lever (orange knob) and shift lever (black knob).
This little tractor is the combination of a 1944 Fairmont railroad section car engine and a 1972 Simplicity Model 728 garden tractor. I restored the engine 30 years ago after finding it in Minneapolis. It had been resting on its flywheels on the floor of a garage for some time and was quite dirty. I was a little surprised when I gave it a push and found the flywheels would turn. Immediately interested, I asked if it was for sale. A few minutes and $30 later, I became a Fairmont owner.
I could hardly wait to place a call to Fairmont Railway Motors in Fairmont, Minn., to ask some questions about my new engine. The serial number, 66252, was all they needed to tell me the engine was a 1944 Model QBA, Series B, sold to the Minneapolis and St. Louis railroad in 1944. This was exciting! Back in 1944, we used to listen to the section cars, "putt-putts" we called them, go through our hometown of Lindstrom, Minn. The Great Northern tracks were only a couple of hundred feet from our house.
The restoration of the engine was made easier because nothing was broken and it had very good compression. The two rows of ball bearings on the pulley end of the crankshaft and the one row on the other end didn't seem to have excessive play, so I didn't have to remove the flywheels and crankshaft. After cleaning and sanding it thoroughly, I gave it a shiny new red and yellow paint job. I had the cast aluminum water hopper sandblasted by a local abrasive blasting company. The cast aluminum carburetor just needed to be cleaned inside and out. All the ignition parts were okay. An oak cradle now supports the gas tank between the flywheels over the crankcase. Often on section cars the tank was mounted on the chassis of the car, next to the engine.
Fairmonts use a Model T Ford-type buzz coil for ignition, and as luck would have it, one of the two coils in my engine stuff was painted gray and stamped on the side with "Fairmont Railway Engine Co." I mounted the engine on a wood base with a box on one end for the coil and a 6-volt battery.
I gassed it up with some 2-stroke mix, squirted some oil into the main bearing oil cup on the pulley end of the crankshaft, and closed the ignition knife switch. With the spark retarded about 10 degrees and one hand on each flywheel, I pulled it slowly through a couple of cycles. There was no turning it fast, because with 84 cubic inches of displacement, getting it over the top just once is an achievement. On about the third or fourth try, the old 2-stroke fired up with a real loud "Fairmont bang." The thrill I get when one of my engines starts for the first time is so exciting I just stand there and laugh. With no pipe or muffler it was very loud.
A month or so later, my wife and I took a trip to the Fairmont Railway Motors Co. We were warmly received and congratulated in obtaining one of their engines. They gave us a very thorough tour of their manufacturing facility, including the aluminum, cast iron and brass foundries. They also presented us with a brand new owner's manual and several gaskets they thought might come in handy.
For the next 30 years or so, I started the engine now and then just for fun. People within a block or two would hear it and sometimes come to watch.
The Fairmont needed some kind of wheels, so after being inspired by seeing a garden tractor at the Almelund Threshing Show sporting a hit-and-miss engine, I decided to find a tractor for my engine. I didn't have to look very far - one of my K-Mart breakfast buddies in the small engine and garden tractor repair business happened to have a 1972 Simplicity Model 728 without an engine. What luck!
I bought the tractor and immediately got to work removing the parts that weren't needed with the new power plant. I took parts off right down to the bare backbone of the little tractor, so all that was left was the front suspension at one end and the 3-speed cast iron transaxle on the other. I removed a lot of accumulated, oily, caked-on dirt with a screwdriver, then scrubbed the whole thing with solvent and a product called Melaleuca MelaMagic, a household cleaner. Without all the dirt it looked pretty good.
It took quite a few additional hours of prepping the tractor for its new paint. After I had the Simplicity Orange paint laid down, the tractor's chassis and sheet metal rear fender looked like new. I also cleaned all four wheels and painted them silver. The rear tires were still serviceable, but the front ones needed to be replaced.
The chassis needed four new holes to mount the Fairmont. Fortunately, the exhaust port on the bottom of the engine lined up with the hole in the chassis where the vertical crankshaft of the original engine passed through.
Now the task at hand was to design and make all the necessary parts to control the engine and get the power from its flat pulley to the v-pulley on the tractor's transaxle. I also had to come up with an exhaust system that would tame the Fairmont's loud exhaust.
The throttle and spark advance are controlled by rods visible in the photos. The drag on the spark advance is built into the engine. The drag on the throttle is created by the force of a tension spring dragging on the control rod. The exhaust pipe required a lot of thought and could not be dealt with until the jackshaft and drive belt path on the bottom of the tractor could be determined.
I turned the 4-inch crowned belt pulley for the jackshaft from aluminum stock. After experiencing some belt slippage, I added rubber lagging held on with screws and 3M Scotch Grip 1300 adhesive. The 1-inch diameter jackshaft runs on ball bearings at each end and has an 8-inch v-pulley in the center. The aluminum belt tensioner also runs on ball bearings pressed into each end. The tractor is articulated, so it has a longitudinal roller bearing structure in the center of the chassis. In order to route the lower part of the 86-inch v-belt from the jackshaft over the roller bearing structure to the input pulley on the transmission, I installed an aluminum roller running on ball bearings ahead of the structure. The tractor's belt tensioner pulley runs on this belt for clutching purposes. This pulley is controlled with the lever next to the steering column and can be operated either by hand or foot. Squeezing the brake on the clutch lever actuates a caliper that stops the input pulley of the transmission for clash-free shifting.
A cable attached through a pulley system to an arm on a common brake pedal shaft actuates the stock brake band on the transmission. Both foot pedals rotate the brake shaft.
I raised the seat 7 inches and moved it back about the same amount to keep the driver a comfortable distance from the engine. The batteries and coil are located in the box that serves as the seat riser. It was also necessary to lengthen the steering column and move it back.
The muffler is a replacement for a small Ford car and came with a convenient flange on the inlet pipe. Inch-and-a-half galvanized pipe makes up the exhaust pipe between the engine and the muffler.
Since its "completion," I have installed a Nippondenso alternator from a Honda passenger car to supply power to the headlights and tail light I added. The alternator runs at 1,200 RPM at idle. I arrived at the alternator speed by installing a 4-1/2-inch pulley on the jackshaft and a 2-inch pulley on the alternator. I then installed a belt tensioner to keep the belt from slipping. Because the coil for the Fairmont operates on 6 volts and the excitation for the alternator and lights operate on 12 volts, I am using two 6-volt motorcycle batteries running in series with the alternator across both of them and the buzz coil across just one of them. I also installed a choke for easier starting in these cold Minnesota winters.
It took me a little over a year to make the conversion. I spent many hours in my machine shop designing, fabricating parts and painting. I had a good time driving the tractor in six tractor parades, and just here and there during the 2004 season. Show goers really get a kick out of how the engine rotation can be reversed on the fly. Because first gear has a much higher ratio than reverse, I'm sometimes seen backing up in first gear with the engine going backwards to keep the speed down.
Contact engine enthusiast John L. Magnuson at: 4640 Ensign Ave. N., New Hope, MN 55428; (763) 533-5787.