Starting Systems for the Diesel Tractors
Two cylinder pony, V-4 pony, 24 volt starter

Beginning with the model R in 1949, Deere enginners had to figure a way of starting the big diesel engines. Hand starting; the very common way to start the tractor engines of the day, was NOT an option. While the R only had 416 cubic inches of displacement (in comparison, the kerosene fueled hand start D had 501 cubic inches), its compression ratio of 16:1 made hand starting with the flywheel impossible!

The electrical systems of the day could not handle the job either. 6 volt systems had no chance, and experiments with 24 volts failed as well.

So it was finally decided that a starting engine needed to be used. A starting engine is a small gasoline engine that is used to crank over the larger diesel engine. This concept had been proven successful with various earlier diesel engines, including some Caterpillar tractors.


Opposed two cylinder cranking engine
Used on the model R, often called "Pony Motors"

The R ended up with a Deere built and designed opposed two cylinder cranking engine, as pictured here:

	Arrow is pointing to front of "tractor" #1: Transmission. Underneath is the pinion (gear) for engaging the diesel flywheel. #2: Housing for optional rope pull start. Curved tube sticking out the top would have rope. #3: Cylinder, with sparkplug #4: Magneto #5: Gasoline tank #6: Electric Starter
	Arrow is pointing to front of "tractor" #1: Carburetor #2: Magneto #3: Cylinder, with sparkplug #4: Gasoline tank #5: Electric Starter

This little engine had a bore of 2.6 inches, and a stroke of 2 15/16 inches, with a displacement of 24.6 cubic inches. It idled at a quick 4000 RPM and when opened up, ran at 4400 RPM! Ignition was a Wico X magneto (modified to work in the opposite direction as most other Wicos). The engine was started with a normal 6 volt automotive starter, or in a pinch, with an optional pull rope (similar to small lawnmowers of today).

The cranking engine shared its coolant with the diesel and when running, it would heat up the water in both engines, like a modern block heater. The engine's exhaust was also routed around the diesel's air intake which warmed that air. Thus, the engine was ideal for use in colder climates, as it allowed all weather starting of the diesel.

For more details of the cranking engine engagement to diesel for starting and warmup, click on these pages:


The normal procedure for starting the R is as follows:
#1: Turn on fuel for cranking engine (C.E.)
#2: Start C.E. and let it warm up
#3: Decompress the Diesel engine, and engage the C.E. to the diesel
#4: Throttle up C.E. (if equipped with a throttle)
#5: Crank Diesel with no compression until it has oil pressure
#6: Release the decompression lever
#7: Advance diesel throttle, engine starts, disengage C.E.
#8: Shut off C.E. fuel, and allow C.E. to stop




V-4 cranking engine
Used on the model 80, 820, 70, and on some 830, 840, 720, 730
Often called "Pony Motors"

Deere's model 70 tractor was introduced with a diesel engine option for the 1954 model year. It's narrow hood and lack of avaliable space for a cranking engine required the design of a more compact C.E. A little more cranking power was needed, especially for the 70's bigger brother that was coming in late 1955 (the 80). Thus the V-4 cranking engine was born!

	Arrow is pointing to front of "tractor" #1: Transmission. #2: Carburetor #3: Valve cover, two sparkplugs are visible underneath #4: Distributor #5: Electric Starter
	Arrow is pointing to front of "tractor" #1: Air Cleaner #2: Pony Water Pump #3: Transmission #4: Transmission, pinion (Gear) for cranking diesel is underneath #5: Carburetor

As originally introduced with the 70, and used on the 80, the V-4 had a bore of 2 inches and a stroke of 1 1/2 inches, displacing 18.85 cubic inches. It idled at an insane 5000 RPM, and at full throttle turned 6000 RPM! Ignition was with a specially made Wico distributor, that had two coils, condensors, and points. It used a 6 volt system for the starter, but the distributor ran at a slightly lower voltage through a resistor, at about 4.5 volts. There was no provision for hand starting the V-4, so you had to have a good battery!

Just like the earlier R pony, the V-4 shared coolant with the big diesel, and warmed up both engines. It's exhaust was again routed around the diesel air intake to give that engine a breath of warm air.

Here is a picture of water circulation through the V-4 and diesel. Note the thermostat in the V-4 that allows it to warm up properly, before moving warm water to the diesel:


During the 80 production, there were few changes to the V-4. The only notable change I saw was the addition of a greaseable clutch release collar at #8001700.

With the beginning of the 820 tractors, the V-4s got new connecting rods and changed governor controls that gave it slightly slower RPMs. It now idled at a meager 4000RPM, and topped out at 5000RPM!

At #8203100, the pony motor recieved quite a few changes and the little engines even got their own serial numbers (starting with SE1000). The improvements included a new crankshaft with bigger main crankshaft journals, oil pump parts, cylinder heads, and a improved fuel system with a sediment bowl and oil pressure shutoff. The air cleaner was improved and moved so that it could be serviced without removing the tractor's hood. There were also changes in the water pump, govenor, and even the transmission! The crankcase also held an extra 1/2 quart of oil (1 1/2 total).

The normal procedure for starting an 80, 820, 830, or 840 with a cranking engine is:
#1: Turn on fuel for cranking engine (C.E.)
#2: Turn ignition switch to "I" postion
#3: Start C.E. and let it warm up
#4: Decompress the Diesel engine, and engage the C.E. to the diesel
#5: Throttle up C.E.
#6: Crank Diesel with no compression until it has oil pressure
#7: Release the decompression lever
#8: Advance diesel throttle, engine starts, disengage C.E.
#9: Shut off C.E. fuel, and allow C.E. to stop
#10: Shut off ignition switch after C.E. shutdown. Not doing so may burn up ignition parts!




24 Volt Direct Electric Start
Used on some of the model 830, 840, along with the late 720, and 730

Introduced in 1959, the 830 continued to use the proven V-4, but now that there had been time to iron out problems with a high voltage electrical system; there was an option for those that didn't want or need the advantages of a cranking engine (pre heating, non stop cranking): the 830/840 was given the option of a 24 volt, direct electric start.

Here is the starter used!

Picture provided by www.classicgenerator.com Thanks!
The new 24 volt system required a few changes. First of all, the small 6 volt battery box was replaced with one that could hold four 6 volt batteries wired in series (battery posts are connected negative to positive). This gave 24 volts, with a high amperage. Of course, this also required the use of a 24 volt generator.

However, all the accesories, such as lights; were only 12 volt! So the tractors had very complicated wiring!

With the 24V system, some things were removed, including the V-4 (of course), and its accesories like the gasoline tank, choke linkage, throttle linkage, fuel shutoff linkage, etc. This required a new instrument panel without the holes that these various controls needed. The cranking engine engagement lever was also removed, but the decompression lever remained. Removal of the V-4 also meant the tractor lost a half gallon of coolant. The diesel air intake was changed, as there was no pony exhaust to pre heat it. A crankcase breather was also added, formerly this was done through the pony air intake.

The 24 volt system was mainly for tractors used in warmer climates, but there were block water heaters and oil heaters avalible for use.

Starting an 830 with the 24 volt system was much simpler and quicker than the pony motors:
#1 Turn on ignition switch
#2 Push starter button
#3 Advance Throttle, diesel engine starts
#4 Turn off ignition switch

In cold weather or with a cold engine, the decompression lever could be used to allow the diesel to begin rolling over easier. It was then released, and the engine started normally.