|All photos with blue borders expand if clicked|
|John Deere Model R after 61 years|
|Model R pulling Compressor|
|Model R left side|
|Model R left side|
|Model R right side|
|Model R Operator platform|
|Model R Starting motor|
The 2 cylinder John Deere Model R shown here is an old friend of the VanNatta Family (could it be an antique farm tractor) which has lived with this writer literally most of this writer's life. What we see is a 1950 Model 'R' John Deere as manufactured by Deere & Co. It joined the family in 1954 at the astounding cost of $3,000, having sold new in 1951 for around $5,000.00. According to the John Deere's history quoted below, the Model R was introduced at about 34 Horsepower in 1949. This is possible, but all the product information sheets available in the early 1950's reported it as 45 hp on the drawbar and 50 hp on the belt.. In the tractor pull contests which require 'stock' tractors, this brute never fails to be the winning model in its horsepower class. After all, pulling power is primarily a function of weight, and since this machine is the heaviest tractor in its horsepower class, it wins. We've never taken this one to a tractor pull contest but we have seen this model there. It is no contest. In its day, it was the biggest thing on rubber tires that a farmer could buy. I recall in the first years that we had it, people would gather around to watch when this 'jonny popper' showed up to till a field.
A 2-cylinder engine of this type by its nature fires unevenly since it is a 4 cycle engine, but must have one piston up and one piston down for balance sake. When it lugs down, and it will lug way down) you start hearing very distinctly the cha-chug cha-chug. Put it in a real hard pull, and the torque roll will buck the front wheels up a little when the 2 cylinders fire one after the other, and then it will settle down for the 3/4's stroke, and then cha-chug cha-chug again.
According to a former John Deere design engineer with whom I spoke many years ago who claimed to have had a hand in the design of this tractor, the Model 'R' was designed against the CAT D-4 as a reference point. It was suppose to sell into the market for heavy tillage in Western Wheat fields and out perform a D-4 Farm Cat in every respect possible. It was to be cheaper, faster, more economical to operate, and get more work done. If this was indeed the design goal, it was accomplished.
You see prior to this time John Deere had been making tractors which ran on gasoline or stove oil and this model was their first production diesel model. The written history of Deere & Co John Deere's Company by Wayne G. Broehl, Jr. (Doubleday & Co 1984) reports on the advent of the Model R as follows:
By the end of the war, the Deere Manufacturing and marketing teams came to believe that the Model D was no longer commercially viable. Though it had been upgraded through its product live--mounted on rubber in the early 1930's, restyled in 1939, increased in horsepower in 1940--it was nevertheless becoming inadequate for the wheatland farms, which were growing bigger and demanding a standard tractor with even greater power. The goal now became increase power, and to generate the power from a diesel. By 1949 the company was a ready with its Model R, the first diesel-powered tractor Deere had ever manufactured. It was also the most powerful, rated at 34.27 horsepower at the drawbar and 43.32 at the belt. Charles Stone, by this time the vice president of for product development, impressed with the enormity of the new machines, said unequivocally, "We see the limit here to the rubber-tired tractor--after this, it has to be a crawler." (today wheeled tractors of more than 200 horsepower are not uncommon!)
The Model R had a gasoline-fueled auxiliary starting engine, which eased two problems that had plagued earlier diesels. Most diesel tractors had been started by the operator standing on the ground, manually turning a flywheel; the Model R was started by the operator in his seat pulling a lever. The earlier diesel had been notoriously difficult to start; the Model R auxiliary starting engine enhanced warm-up; allowing fast start even in cold weather. To the relief of everyone, the new tractor was greeted with enthusiasm by the trade; Deere was back in the running, with a good diesel engine.
This tractor has the classic 2 cylinder John Deere design with a horizontal engine. The huge flywheel hangs out on the left and the belt pulley/clutch on the right. The classic hand clutch consists of multiple dry disks inside the belt pulley and can be readily serviced (and realigned) by merely unfolding the cover from the belt pulley. the 'live' PTO is driven from a gear train which starts on the crankshaft inside the flywheel. Bore and Stroke are approximately 5.25" by 8" and maximum RPM is about 1000, RPM. It may be a coincidence--I doubt it--that the Bore, stroke, and RPM are identical to a configuration used by Caterpillar (with more cylinders) in their larger bulldozers dating back to 1937. Even the gasoline 'pony' engine or 'goat motor' is of a configuration similar to that featured by Cat on their smaller tractors of the era. Unlike the Cat Goat motors that used a float carburetor, Deere used a simple 'sucker valve' carburetor. The gas tank is a quart can that screws into a 'Mason jar lid', so to gas this tractor you actually unscrew the 'gas tank' from the tractor and fill it up and then screw it back on to the tractor.
The radiator holds an astounding 13 gallons of water and the engine lacks both a thermostat and a water pump. The radiator and the fan are generally higher than the engine and the cooling design relies on 'thermal-siphon' for its function (hot water goes up). Our tractor has an optional radiator shutter which helps in the 'warm up'. The goat motor has an electric start on it (unlike the Cats of the day which often used a rope start on the gas engine).
There are actually 2 levers used to start the diesel. One is a compression release on the Diesel and the other is the pinion control. To start the tractor, you first start the 'goat motor' as you would start any small electric start gas engine. Once it is warmed up, you release the compression on the diesel and engage the starting pinion to 'spin up' the diesel motor. You then open the throttle on the diesel and release the compression release. The engine should buck over and start at once. If it doesn't, you Shut off the throttle (to avoid excess diesel in the cylinders) open the compression and spin up again. The goat motor will just barely turn the diesel motor with the valves closed ( with compression) so some coordination of the throttle opening/ compression release setting is required. The difference between a battery start and a gas engine starter is that unlike the battery start, the longer you wrestle with it the easier it starts. This is because the goat engine shares a water jacket with the diesel and because the exhaust from the goat passes through a crude heat exchanger preheating the air entering the diesel. This engine features a 16:1 compression ratio and always starts immediately in above freezing weather conditions. As with any diesel, things become more interesting as you drop the temperature into the sub-freezing range. After all, a diesel relies on compression ignition, and to achieve this inside of a big blob of very cold cast iron is quite a feat. Sub zero F temperature are rarely seen in this writer's local, but over 40 years of experience with this machine in temperatures approaching zero from the top side have never produced a day when it was too cold for this tractor to start.
We've never been too sure the hour meter was accurate, but it says around 9,000 hours now. This tractor is still running on its original injectors and injector pump. Somewhere around 30 years ago, the tractor had an 'inframe' overall in which the main and rod bearings were replaced. and the cylinders were bored and fitted with oversized pistons. Actually the engine wasn't all that 'worn out ' then but a head gasket failed and let antifreeze into the cylinders which did not do nice things to it. The tractor is running on its 3rd set of tires which isn't too bad for a tractor built in 1950.
When we have plowed with it, we have generally used 3-16's though John Deere classed it at the time as a "4-5 plow tractor" on the basis of the classic formula of 10 horsepower to the plow. Years ago when our neighbors were running stationary threshers we rented it out to them one season to run a thresher (off the belt pulley). They reported that the most aggressive crew with pitchforks couldn't stall it. Deere needed their first diesel to be a reliable one and after driving this 46 year old tractor around for over 40 years, this writer is beginning to suspect that this tractor is reasonably reliable. At the moment we see no particular reason why it won't chug into the next century.
Deere equipped these tractors with pretty good internal expanding drum/shoe brakes and provided a decent hydraulic system which supports one remote cylinder. Features which we take for granted today which are lacking include power steering and a 3 point hitch. Both were unknown to farm tractors when this machine was built, though the power steering did begin to appear i n some tractors in the early 1950's. The operators platform features 360 degree air conditioning, and like all John Deeres of the day, is configured to that the tractor can be operated equally well standing up or sitting down. The platform is large and flat and the brake pedals can easily be applied either standing or sitting. Likewise the steering wheel is high enough to reach in the standing position even though it is not adjustable. The hand clutch can likewise be reached from the standing position. Indeed, one can get more force on the steering brakes while standing and can actually apply more leverage to the steering wheel as well so when the going gets real tough the tendency is to stand even though today the concept of standing up to drive seems odd.
This 55 year old tractor completed 50 years of service this year, having baled our hay every year for 50 years, plus done other jobs as well. One of the ironies of this photo is that the compressor in the trailer behind the tractor has a Deere Industrial engine which is about 2 feet long, but about as powerful as the engine in the Model R. The engine in the Model R is horizontal. The clutch is on the end of the crank shaft and is concealed inside the belt pulley. The flywheel hangs out on the other side of the tractor, and the tappet cover is nearly to the radiator.