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America's most exciting row-crop tractor International 1468 and 1568 tractors fill a marketing void
Oscar H. Will III

When International Harvester marketing executives learned of the development of a V-8 powered row crop tractor at Massey-Ferguson in the late '60s, they put the pressure on the Farmall Tractor Group to come up with a plan for a V-8 model of their own. "From my standpoint, the project idea emerged out of our marketing department," Ed Harnach, a retired IH engineer who worked on the 1468 project from its inception says. "The concept of a V-8 in a farm tractor at the time gave the image of power, and that was an attractive image."

The IH V-8 tractors sold from 1971 to 1976 were only a mild success, offering, for Farmers, little extra to the 6 cylinder tractors, besides looks, sound, and image. "The 1468 was essentially a 1466 with a few modifications for the DV-550 engine," Ed says. The engine was adapted from IH's Motor Truck division, and neither the 1468 nor the 1568 had more horsepower than their 6 cylinder counterparts.

"The tractor was a show piece and it looked real nice in the field," Dick Lantis says of the V-8 models. Dick farmed with the machines and sold them at his Stockton, Mi. International Harvester dealership. "They sounded nice under a load, but a little strange otherwise," Dick adds, making reference to the unique fueling system that fired only four of the cylinders when the work was light. "It could do the work, but so could a 1466 or 1566, and they had the simpler and more agriculturally proven 6 cylinder inline diesels," he adds.

With their distinctive twin exhaust stacks and heat-shielded mufflers, the '68s are hard to miss. Harold Schramm, a former IH engineer in the Advanced Projects group, says that the folks in the marketing department felt sure that the 1468, with its shiny heat shields and stacks, would appeal to the younger farmers, just as the dual stacked class 8 road tractors of the time appealed to the younger truckers. While they may be considered show pieces by many, and hotrods by others, the 1468 and 1568 had the same care in engineering as all other products that came out of the Farmall Group at IH.

From paper to production
"One of the biggest design hurdles on the 1468 was overcoming the nonstructural nature of the crankcase on the DV-55O," Ed Harnach says. Since the 549 cubic inch displacement DV-500 engine was designed for trucks, boats and stationary power systems, it was never meant to be part of a tractor's superstructure. And although IH had put side rails on their tractors for years, they really did not play a significant structural role. "Oh, we had side rails on all of the row crop tractors at that time," Ed explains, "but they were really for hanging weights and implements on the tractor; the real strength came from the engine tying the rear of the tractor to the front end."

"The solution was to design new frame rails and make them out of nodular cast iron," Ed explains. Since side rails were standard on IH tractors, Ed's group was able to make significant changes to the 1468's frame while keeping the look of the 66 series tractors intact. Thus the 1468 got its fore-aft strength from the frame and not the engine's crankcase. Marketing pieces on the 1468 make note of the stronger frame rails, but not the real reason for their incorporation into the tractor's design.

Once the big V-8 engine was hung in the chassis, Ed's project team tackled the difficulty of exhaust routing. Typical truck manifolds delivered exhaust toward the rear of the engine, which would have put the mufflers and stacks next to the operator's platform or cab if equipped. The heat, and the potential for burns to the operator was too great, so Ed's group designed a new manifold that collected the exhaust at the front of the engine. For added safety and styling, they also designed attractive yet functional heat shields for the mufflers.

Although most row crop tractors have their engines contained within their frameworks, the DV-550 didn?t fit neatly inside the traditional engine compartment for the 66 series tractors. In fact, some operators criticized the tractor because of the engine's overhang, which they felt would snag taller crops. Ed's worry about the width of the engine was more fundamental. "The engine stuck out beyond the frame enough that the hot manifolds would pose a significant burn hazard," Ed says. 'so we decided to add heat shields to the manifolds too.?

Initial testing with the shields in place indicated that they were effective; however, after several heating and cooling cycles, the fasteners that held the shields in place broke. "It took us a while to figure out why the half inch cap screws were getting their heads popped off," Ed says, as he explained that the final flexible mounting system allowed for expansion and contraction of the shield. With the 66 series frame modification and the DV-550 installation completed, the 1468 V-8 tractor was ready for production.

Amidst the excitement
The Farmall 1468 was released along with the rest of the 66 line in late 1971 with 133 hp the same as the 1466. By the time it was tested at Nebraska in 1972, the 1468's output measured 145 hp, which was matched by the 1466 and did not change until 1975 with the introduction of the 1568.

At its debut, IH advertised the 1468 as "the maximum in farm tractor prestige design." IH marketing literature claimed that the DV-500 engine was designed for farm tractor use and that it met all smoke emission requirements at the time. As a point of fact, the engine was not specifically designed for the tractor, but there were some ag-duty only specifications.

The DV-500's fueling was innovative and reliable in the 1468. When the load was light, the Bosch mechanical inline injection pump sent fuel to cylinders 1, 4, 6, and 7. When the need for power was greater, all eight cylinders got the juice. While this stepped injection system provided additional fuel economy, it sounded unusual and many operators modified the pump to bypass the system, sending fuel to all 8 cylinders all of the time.

The DV-550 featured a sleeveless integral cast block and crankcase. The crank turned on 5 main bearings for a 4.312 inch stroke which at the standard bore of 4.500 inches yielded 549 cubic inches of displacement. The pistons were cooled from below with a spray of high-pressure, filtered oil, and the combustion chamber was molded into the aluminum piston's dome.

While the Motor Truck division offered a turbocharged version of the engine called the DVT-550, it was never incorporated into an agricultural tractor. IH offered a number of turbocharged tractors during the life of the 1468, and a 1468 with a turbo decal on its hood is shown in the 1974 Buyer's Guide, but there was no such tractor. Later IH literature spoke directly to that marketing oversight. However, a number of vendors and engine builders offered dual turbo kits for the 1468, and often these up-rated engines failed when pushed hard.

"The DV-550 was not without its problems," Dick Lantis says. "It had poorer torque rise compared with the 6 cylinder diesels, and the lower end of the engine tended to be weaker too." In fact Dick recalls several V-8 tractors in the shop at his dealership with broken rods and/or cranks--generally the result of adding turbos and/or adjusting the fuel pump.

The 1468's engine delivered power to the rear wheels through a 14 inch diameter dry clutch in front of a dual range, four-speed, sliding spur-gear transmission coupled to a differential and bull-gear reduction final drive. Hydraulic 11-inch diameter dry disk brakes mounted outboard on the bull pinion shafts provided stopping power. In the standard configuration, the tractor had 8 forward and 4 reverse speeds. With the optional Torque Amplifier (TA), the operator had an effective 16 forward and 8 reverse speeds.

There was no mechanical linkage between the steering wheel and the front axle on the 1468. The system was completely hydrostatic, with an external cylinder actuating the steering arms on the adjustable wide front axle. The hydraulic system included a 9 gpm steering pump, a 12 gpm service pump, and a 3 gpm PTO clutch pump. The tractor was available with a host of hitches, drawbars, fenders, cabs and many other comfort and safety options.

By the end of its production run, just over 2900 of the 1468 model had been sold.

A few more ponies with an improved drive train

The horsepower wars of the '70s were relatively easy to wage by adjusting the fueling of an engine, adding a turbo, or just governing it at a higher rpm. But by the time 1974 came around, it was clear to IH engineers that the version of the 66 series drive train in the 1466 and 1468 was getting close to its hp limitations. To prepare for the inevitability of demand for higher horsepower, the Farmall Group began working on a new transmission and final drive as early as 1971.

The new modular transaxle design included a three-speed dual range transmission with outboard planetary-gear reduction to the final drive. This combination gave operators a choice of 12 forward and six reverse gears with the TA, which was standard equipment in the design. The wet, multi-disk brakes on this system were mounted inside the case and were plenty adequate for the increased stopping loads, although they were much more difficult to service. This drive train combination was able to handle well over 160 hp.

In 1975, the 1468 was replaced with the 1568 at 150 hp, and a new turbocharged 6 cylinder model 1566 with 160 hp was added; both utilized the new drive train. The older style 1466 was retained, and it was still rated at 145 hp.

The 1568 had an ?improved? version of the DV-550 engine with higher compression pistons and a higher pressure fuel system. The Bosch inline injector pump was changed to deliver fuel to cylinders 2, 3, 5, and 8 during low power operation. The cylinder heads were redesigned to provide more valve recess, which avoided interference with the higher dome pistons. There was still no turbo available in the 1568 from IH.

With the DV-550 pushed to its 150 hp naturally aspirated max, there was really no future for the 1568. The day of the IH V-8 show tractor was fast ending. Farmers had even less reason to go with the DV-550 engine than before--10 horsepower less -- with no durable upside. During its short production run in 1975 and 1976, the 1568 sold just 862 units, which to Ed Harnach was a disappointment. "We looked for sales numbers in the 10s or hundreds of thousands to measure real success," he says.

Today, the V-8 models 1468 and 1568 have quite a following among collectors and IH enthusiasts. Some of the tractors are sequestered in private collections, and some are still at work in the field. Many others were re-powered with the venerable DT-436 inline 6-cylinder turbocharged diesel engines found in the 1466 and 1566 tractors. Today, good, original condition examples of either V-8 tractor are hard to find.

IH set out to make a functional but showy tractor with the 1468, and they did that superbly after some key adjustments to the 66 series design. Whether either V-8 powered tractor lived up to IH's claim that it was "America's most exciting row-crop tractor" is really a matter of personal preference. However, when you see people's eyes light up, heads turn, and crowds gather when one of these machines is fired up at a show, you will know what the excitement was all about.

-Oscar "Hank" Will III is a freelance writer with a passion for machines and the people who love them. He retired from farming in 1999 and academia in 1996 and splits his time between his home in Whittier, CA, and his farm in East Andover, NH. He collects and restores vintage IH tractors and Cub Cadets, and travels the country in search of good stories. Write him at 13952 Summit Drive, Whittier, CA 90602 or call (562) 696-4024; email: willo@gettysburg.edu

Captions:

1468a.jpg: The 1468 Farmall made the cover of the Spring 1972 IH Buyer's Guide and is shown here pulling what appears to be an 8 bottom plow?which was not listed in the Buyer's guide. Note the aluminized mufflers and heat shields. This particular tractor is equipped with the optional pressurized cab and the exhaust stack extensions.

1468b.jpg: At its debut the dual stacked 1468 was rated at 133 hp. Once the tests were completed at Nebraska in 1972, the tractor had 145 hp and that didn?t change again for the life of the model.

1468c.jpg: In 1974, IH marketing focused a little too hard on the turbocharged lineup of 66 series tractors. Here, a naturally aspirated 1468 tractor is mislabeled and the caption calls the tractor a 1468 Turbo, and although it never indicates whether the tractor had one or two turbos?in fact it had none. In later marketing pieces, IH called attention to this error and corrected it.

1568a.jpg: A proud Dick Lantis at the wheel of his low hour 1975 International 1568. Dick has had the heat shields, stacks, and valve covers chromed, and unlike many original condition units, the injection pump still feeds only four cylinders under light load.

1568b.jpg: Left side view of the 1975 International 1568 owned by Dick Lantis.

1568c.jpg: Detail of the PTO and three-point hitch on Dick's 1975 1568 tractor. Note that even in 1975, the lower links were able to accommodate International's proprietary two-point Fast Hitch equipment.

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