Tractor heritage, news and features

Red Bulls

Each of us has a favourite brand or model of tractor which will get the pulse racing, and some are fortunate enough to have access to many books that deal with the history of companies and their favourite tractors. International Harvester wheeled tractors are widely written about. Entire books on the revolutionary Farmall models feed the hunger of enthusiasts for knowledge of the development of this breed; but what about the crawler tractors which shared the engines and styling of the letter series Farmalls?

A few books give details of specifications and the University of Nebraska test results for the International crawlers, but the history of the steel track machines seems to be passed over unnoticed.International Harvester was a diverse manufacturing giant famed for wheeled tractors; but as it watched the merged Best and Holt companies as the Caterpillar Tractor Company rapidly increase sales for its track-type tractors, International developed a range of competent machines during the tough years of the 1930s to compete with both Caterpillar and survivors of the Depression like Allis Chalmers and Cletrac.

A new range of tractors

By the end of the 1930s, International had a new range of diesel and distillate-engined tractors ready to replace the original TracTracTor models. Given the ‘in house’ styling to match the recently revised wheel tractors from the renowned industrial designer Raymond Loewy, the new TD series of crawler tractors looked part of one very large and powerful family.

The first tractor in the crawler range was the TD18; aimed at the Caterpillar D7 size tractor, the six-cylinder engine with its twin exhausts was a good machine suited to earthmoving. It was soon joined in 1939 by the mid-range TD-14 and TD-9 tractors with four-cylinder International diesels with the smaller three-ton TD-6 completing the line-up in 1940.

The sales figures prove the popularity of the T and TD family, which totalled around 146,000 tractors manufactured in the United States between their launch and the mid 1950s, when a redesign heralded thousands more TDs.

It is not only written details on the International crawlers that are in short supply for the enthusiast, but also parts for the TDs are very hard to find in the UK. Running gear and engine parts have long been scarce; service books appear quite often, so the knowledge is there, but the frustration is that the parts required generally are not.

Not deterred

The difficulties of parts supply has not deterred Jimmy Long from collecting International Crawler tractors built in the USA or Doncaster. Much of the stuff he has bought was at scrap price and often the haulage to get dead machines home exceeded the purchase price. A number of Jimmy’s friends locally also own International crawlers and each encourages the other to complete the more challenging parts of the restorations.

When Jimmy began his working career, he was involved with ploughing open hill land for the first planting of conifers in the 1960s. Some of the easier ground was ploughed using Doncaster-built BTD6 crawlers and specially designed single-furrow forestry ploughs.

The need for floatation required the BTD6 to have the long five-roller track frame and wide pads. Extra wide pads were built by welding half another worn pad with little depth on the grouser bar on the outside of the existing pad on the chain. This floatation track put strain on the running gear and transmission but the little BTD6s took it.

With examples of the BTD6 in his collection, Jimmy began to search for the larger International TDs. Finding tractors like the TD-9 and TD-14 in Britain was a difficult task. Like the American Army and Air Force, the British equivalents shared a preference for Caterpillar tractors, and the few Internationals were disposed of soon after the war at big dispersal sales.

A number of TD-9 tractors came to Britain through the Lend-Lease Agreement for agricultural use in both standard 44-inch gauge and wide 60-inch gauge. At 38.9 drawbar horsepower from a 334 cubic-inch four-cylinder diesel, the TD-9 was a close match to the Caterpillar D4 of 35 drawbar horsepower.

While the D4 relied on a horizontal two-cylinder petrol engine to start the main engine, International continued to use the petrol start diesel found on the earlier International TD-35 and TD-40 tractors. This original system had an automatic changeover from petrol to diesel by closing the third valve in the diesel cylinder head after a fixed number of engine revolutions. On the 1939 TD series, the operator decided when to change over to diesel once sure the engine had warmed enough to support compression ignition.

Watching Jimmy start the TD-9, on a cool day, the engine was changed over to diesel after about a minute. The 12-volt starting system to crank the main engine which was briefly a four-cylinder donkey engine started running as a compression ignition engine faster than its competitor without the chore of winding the starting rope round the Caterpillar donkey engine a couple of times and engaging the starting clutch.

The TD-9 was bought from Somerset. The tractor once had Bucyrus-Erie bulldozing equipment fitted, all but the front-mounted hydraulic pump had been removed. The tracks were rusted solid so the TD-9 was lifted onto the transport by a pair of wheel loaders.

Bought for scrap

The tractor was bought for scrap money which proved less than the haulage to get the thing home. The power take-off was found while the tractor was undergoing restoration and fitted a couple of years ago. Some cosmetic parts have still to be located, including the rear sprocket guards, proof that parts for these TDs are just not around in the United Kingdom. Since just under 60,000 of these tractors were built from 1939 to 1955, a suitable breaker for these parts could well be found in the USA.

A successful model

Moving up a model, the TD-14 arrived from a collector in Cambridgeshire who had begun the restoration and partially stripped the TD-14 before deciding to sell it. The TD-14 had worked on one farm all its life, which made it an attractive buy even in kit form for Jimmy Long, as his experience with the TD-9 suggested the TD-14 was worth a try at the money he paid for it.

The TD-14 was built in its original form from 1939 to 1949 when it was replaced by the TD-14A, which was manufactured until the mid 1950s. The first series gained a reputation for cracking cylinder heads and the A series had changes incorporated in the head design. Incorrect operational procedures when cooling a hot engine were the cause of many head failures with International petrol-start diesels. The engine should be cooled by idling for several minutes after prolonged heavy work, then changed to petrol running for a couple of minutes, then finally reset to the diesel position so that the third valve is closed and seated. As replacement cylinder heads are not readily found, care needs to be exercised with these diesels.

A significant difference

One significant difference between the pair of tractors concerns the gear box. The TD-9, like its smaller TD-6 stablemate, used a five forward speed gear box with one reverse speed. The TD-14 had six forward speeds and two reverse. This was achieved using a Hi-Lo selection lever on the left side of the gearbox. In its standard form, the choice of ratios was intended for bulldozing operations. There was an option for agriculture which gave increased travel speeds in third and sixth gear. Incidentally, the TD-9 could have two reverse gears, the additional reverse being substituted for the third forward gear. The common application of this would be for bulldozers and track shovels.

With over 26,000 TD-14s and more than 12,000 TD-14A tractors leaving the factory, it was another successful model for International Harvester. The TD-14 was quoted as 54 drawbar horsepower which placed the tractor against the Caterpillar R series D6 of 1941 to 1947. International used a four-cylinder 461 cubic inch engine running at 1350rpm in the original TD-14. After the cylinder head changes and lifting the governed speed to 1400rpm, the A series was reckoned to be good for another ten horsepower.

Two track gauges were available; the standard gauge was 56 inches which when supplied on 16-inch pads gave an operating weight of seven tonnes, while the wide model with a 74-inch gauge and 18-inch plates added around another half tonne to the tractor’s weight. The narrow gauge TD-14 is much more pleasing to the eye with its proportions.

Jimmy Long has to be admired for returning tractors from poor condition to useful running and restored machines when there is a high risk that vital parts may not still be about, which could make the tractor unrestorable after time and money has been lavished on the project. To see for the first time that pair of tractors parked in the field ready for the pictures with the spring sun catching the shine on the International red paint raised a smile of satisfaction; this was going to be a pleasant morning. And that’s no Bull!