The First WD-40
1935 McCormick-Deering WD-40

You’re forgiven if  “WD-40” brought something else to mind. Before that incredibly useful product was invented, there was an equally useful product with the same name. However, the two products couldn’t be more different: They began almost 20 years apart, and one is almost forgotten while the other has grown into a household name. While they both were trendsetters in their respective industries and deserve recognition, we’ll let somebody else cover the WD-40 that comes in a can; we’ll focus on the WD-40 tractor that was the first wheeled tractor in North America to run on diesel fuel. 

The World of Diesel-Powered Tractors

International Roots

The story starts with the engine, an idea that germinated with International Harvester in the late 1920’s. Leonard Sperry in the Gas Power Engineering Department headed up a project to develop a diesel engine for International. The initial goal was to use diesel in their newly developed crawler tractors, a concept which Caterpillar was jealously guarding. In the late 20’s, it seemed as if you even had a dream about a tracked tractor, Cat was gonna take you to court over patent infringement. The IH legal team finally got past that but found they were in a race with Cat over the development of a diesel-powered crawler as well. They lost that race, but not by much. Cat produced their first Model 60 diesel crawler in September of 1931 and International produced the first TD-40 in April of 1932.

Differences? There were many. The Cat 60/65 crawler was a much bigger machine than the IH TD-40 and had a much larger engine, 1,090 ci versus the IH at 460.7 ci. Power differed as well; the big Cat made 87 flywheel horsepower at 700 rpm while the IH developed 50.7 hp at 1,100 rpm. We don’t have a flywheel torque spec for the IH but figure the Cat’s 720 lbs-ft at 470 rpm probably has the IH beat. Another big difference was the starting method. The big Cat used a 2-cyl. gas pony engine and the IH started on gasoline for warm-up and then switched over to diesel. This was extremely innovative for the day. Both diesels started with a hand crank directly, or indirectly, in the case of the Cat’s pony engine.

The New W-40 Series

As the TD-40 and it’s new diesel were being tweaked, the major upgrades to the McCormick-Deering 22-36 wheeled tractor were being finalized and that new diesel was intended to be in the lineup. Dubbed the W-40 series, the first debuted in October of 1934 as a gasser, and the first diesel rolled off the line on April 16, 1935 with an initial production order of 25 per week and mixed in with many more gas or kerosene engine units. Diesel production soon ramped up as popularity increased. There were three tractors in the W-40 line, the WA-40 gasser, WK-40 kerosene and the WD-40 diesel.

IH had some bugs to work out on several levels. Initially, some air filter problems caused early engine failures but the elephant in the room was the same one faced by all diesel engine manufacturers of the day: short engine life due to poor lubricant quality. Among other issues, the paraffinic Pennsylvania crude oils cause ring and piston failures in as few as 850 hours. The cure came from Chevron, who developed a special oil from a West Coast crude called DELO (Diesel Engine Lubricating Oil). This increased diesel engine life from 1,500 hours to at least 3,000.

In 1935, the WD-40 had a retail price of $2,225 (about $39,000 in 2015 dollars). The WA-40 retailed at $1,350, so just like today, that diesel power plant added a fair bit to the cost. Lehman’s 1935 has a rear shaft PTO, which we think was a later option that a previous owner added in the distant past. Don’t ask about comfort options. They didn’t exist in this era.

As mentioned earlier, the International diesel made 460.7 ci from a 4.75-inch bore and a 6.5-inch stroke. It started on gasoline and then was switched to diesel after warm-up, while it was still running. It did this via auxiliary combustion chambers that were plumbed to a small intake with a tiny carburetor. With the compression release lever pulled back, a valve was opened from the main combustion chamber to the auxiliary, which contained spark plugs fired by a magneto. With the release open, the compression ratio was 5:1, and the engine could be turned over “easily” (so claimed the sales literature) via the hand crank. After running for a minute or so at 400 rpm on gas, the compression release disengaged, which closed the auxiliary combustion chamber, stopped the fuel to the carburetor and disengaged the magneto. With the compression release disengaged, the injection pump engages and becomes a direct injected diesel with a 17:1 compression ratio. This gas start feature would be present in IH-built diesels to almost 1960. By the way, all the International Harvester tractors were crank start until 1939. The WD-40’s gas-powered brother got an electric start in 1939, but the WD-40 diesel never did.



The W-40 series tractors were the standard tread big boys in the lineup. Bare—the diesel weighed in at 7,550 lbs. on steel wheels though working weight was more like 8,500 lbs. And yes, the W-40 was offered with both steel wheels and rubber pneumatic tires. Rubber tires were still a fairly big deal in the mid-30’s, but with the normal 32 steel lugs per wheel, the steel probably beat the rubber for traction, even if you were spitting out teeth to make the rated 4 mph top speed. On rubber tires, the top speed was 12 mph: fast for the day. The tractor used a 3-speed transmission, and the gearing was different between the rubber and steel tractors.

The sharp-eyed among you may see the “gasoline” decal facing the driver. Don’t freak. Remember, this tractor started on gas, and as a result, carried 1-1/4 gallons of gasoline in addition to the 31 gallons of diesel fuel. The only gauge was the water temp gauge.

The legendary “Armstrong” starter from the days before Mr. Kettering’s electric starter had been applied to many farm tractors. In watching owners start these, we can say it actually doesn’t look all that bad. Easily said by the one not doing it, of course, but swinging over a 461 cubic-inch engine by hand…how hard can it be?

The standard WD-40 tractors had the stuff that was considered important for the day, a temp gauge, seat and fenders. The seat was a pressed steel bucket with no back. Optional was a drum PTO, swinging drawbar, exhaust muffler, plus a lot of attachments for just about any type of farming. The four cylinder WD-40 tractors were a little behind the six-cylinder W-40 gas and WK-40 kerosene/distillate tractors as far as power is concerned (about a horsepower) but way ahead on fuel economy.

The WD-40 engine featured three main bearings and early on had poured babbitt bearings. Around 1937, they adopted copper-backed insert bearings. That year, the injector angle was also changed. The engine was dry-sleeved, had a pressurized lubrication system with an oil filter and used an injection pump designed and built by International.

The WDC diesel was International’s first and had nearly three years of service in the TD-40 crawler behind it by the time it debuted in the WD-40. It developed 51 flywheel horsepower from its 461 ci at a “screaming” 1,100 rpm. We don’t have a manufacturer’s torque rating, but we assume it had about 245 lbs-ft at that same rpm and likely quite a bit more at a lower rpm. The housing in front of the IH injection pump is a fuel filter. These pumps are getting tough to rebuild, and parts are scarce, but there are still experts out there that specialize in them.

If you are not a “red tractor” person, you may be confused with the interchanging of “International Harvester” and “McCormick-Deering” in this story. The McCormick-Deering tractors were products built by International Harvester. International Harvester was formed by the merger of the McCormick Harvesting Machine Company and the Deering Harvester Company in 1902, both of which were developing internal combustion engines and tractors at the time of their merger. Both were prestigious companies with lots of name recognition, so McCormick-Deering was a name that worked to bring fans of both to the company, plus settle a monopoly issue with the government over keeping two separate companies. By the end of the 1930’s, the McCormick-Deering badged tractors became fewer and the International Harvester or McCormick branded tractor began becoming more prevalent. By the late 1950’s, in the USA at least, the McCormick branded tractors were also gone.

The WD-40 was produced until 1940 and was replaced by the much-improved WD-9, which replaced it in the lineup as the big standard tread tractor. Total production of the W-40 line is listed at 10,059 with some 3,400 being WD. The WD-40 was a history-making tractor and one that helped push diesel into the mainstream of farming and commercial use in general. DW

Typical Specifications:
1935 McCormick-Deering WD-40

Engine: International WDC
Displacement: 460.7 ci
Bore & Stroke: 4.75×5.5 in.
*Rated BELT PTO Power: 48.79 hp @ 1100 rpm
*Rated Drawbar Power: 36.52 hp @ 1100 rpm
Compression Ratio: 17:1
Transmission: 3-speed
Weight: 7,550 lbs
Tires: Front- 34×6 steel, Rear- 50×12 steel, Front- 7.50-20 rubber, Rear- 12.75-20 rubber
*Fuel Consumption: 3.35 gph @ full power
Fuel Capacity: 31 gal.
*Drawbar Pull: 4,774 lbs. @ 5.45% slip
*Top Speed: 3.9 mph (steel) 12.4 mph (rubber)
*As Rated by Nebraska Tractor Test 246