MAY/JUNE 2010 ISSUE 009 26 by KENNETH UPDIKE ith the announce- ment of the new line of “Big Red” IH tractors in 1971 (aka the 66 series) a single model in a new tractor series was also announced. This tractor shared the same transmission and final drive as the IH model 1466. This new trac- tor had the same fenders and factory installed cab as the 1466. It even had nearly identical hood work and front grille. But something was very dif- ferent in it. Under the hood was an IH built V-8 diesel engine with a dis- placement of 550 cubic inches that cranked out 140+ PTO HP. This trac- tor had dual exhaust stacks that nearly screamed “look at me!! ...... I am a mus- cle tractor!!!” This was the Farmall model 1468 V-8 diesel tractor. 68 Series DIESEL TRACTORS
Transcript
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by KENNETH UPDIKE
i th the announce-
ment of the new l ine
of “Big Red” IH tractors
in 1971 (aka the 66 ser ies) a s ingle
model in a new tractor ser ies was also
announced. This tractor shared the
same transmission and f inal dr ive as
the IH model 1466. This new trac-
tor had the same fenders and factory
instal led cab as the 1466. I t even had
near l y ident ical hood work and front
gr i l le . But something was very di f -
ferent in i t . Under the hood was an
IH bui l t V-8 diesel engine with a dis -
p lacement of 550 cubic inches that
cranked out 140+ PTO HP. This trac-
tor had dual exhaust s tacks that near l y
screamed “ look at me!! . . . . . . I am a mus-
cle tractor! ! ! ” This was the Farmal l
model 1468 V-8 diesel tractor.
68 Series D I E S E L T R A c T O R S
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IH tested 2 different com-bustion systems, the pre-cham-ber turbulence type and the “M” system more commonly associ-ated with the M.A.N. brand of diesel engines from Germany. The “M” style combustion chamber/piston design proved to be the “right stuff ” for IH and they continued development of the engine with this system.
IH used brand name com-ponents on their tractor for the parts that they did not built themselves. These parts would be mainly, electrical, hydraulic pumps, rims, tires, seats clutches and engine system components. The inline injection pump for the DV-550 V-8 diesel was purchased from BOSCH as were the eight single-hole fuel injection nozzles. The injection lines were built from ¼” OD seamless steel tubing with ball ends to ensure good sealing over a wide range of injection line misalignment.
The DV-550 used dual full-flow spin-on type oil filters that were mounted to the engine oil cooler. These are located on the left-hand side of the trac-tor. These filters are fed engine oil from a gear-driven pump. After the oil is filtered, it passes
For IH, the engine choice for a V-8 diesel had to be one of their own. They chose to use the model DV-550 engine that was developed in the mid 1960’s. The DV-550 was developed at the same time as its little brother the DV-462. Initial research and development of these engines actually started in 1957. IH wanted to have a high
speed V-8 diesel engine that had performance characteristics and size similar to the existing IH large V-8 gasoline engines.
The advantages IH saw with this was to be able to use many of the existing engine production tools, a low total engine weight and weight to power ratio. Power would be made thru high RPM rather than displacement.
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through the oil cooler and then on to the main oil gallery. The crankshaft main, connecting rod and cam bearings are lubricated via drilled holes from this main oil gallery. The front and rear camshaft journals are cross drilled to allow oil flow to the rocker arms, timing gears and fuel pump cam. The pistons are jet spray cooled by excess oil from the pump that passes thru a regulating valve and on to the cooling nozzles.
The engine has dual ther-mostats that sit in a housing atop the dual belt drive water pump. A built in coolant bypass flow is used to allow circulation during cold startups. A coolant conditioner (water) filter was not fitted to the DV-550’s. Since the engine was not a wet sleeve design it was not necessary. The DV-550 was similar to many of the FORD tractor engines in that it was a “parent bore”….aka sleeveless engine. When the en-gine needed overhaul, the block needed to be bored oversize or if that was not possible, the block was bored and fitted with a dry type cylinder repair sleeve.
The dual spin-on style full flow fuel filters (primary and final element) are located on the RH side of the lower engine. These two filters trap any dirt particles before they can damage sensitive injection pump parts.
The DV-550 was originally designed as a truck engine for use in motor trucks. With its success proven in the truck line, the AG division “borrowed” the engine for their own application. It was common at IH for the AG and CE divisions to use engines that were initially designed and built by the truck group in their own applications. With the V-8 diesel engine procured and then mating it to the transmission/final drive of a 1466 tractor, the first model in the new IH 68
series, the 140+ PTO HP model 1468 Farmall was born.
The dual exhaust stacks were quick to catch ones eye when looking as that 1468. The engines valve covers have an aluminum paint color finish as do the exhaust shields on the manifold and mufflers. These contrasted nicely with the IH 2150 red and IH 935 white paint used on other parts of the tractor. On top of each valve cover is a black printed decal that says “International Diesel” to indicate that this V-8 power plant is an IH built item, not retrofit or repower.
Since the engine is a V-8 design, IH used two exhaust mufflers (one for each side) along with muffler shielding and exhaust manifold shielding to compliment its sharp looks.
Besides the obvious use of a V-8 diesel engine with its dual mufflers and manifold shielding the 1468 also had a unique run-
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ning feature. The tractor would fire on only four cylinders under light loads. While most think this was done for economy, this was actually done to smooth out the engine. Under a light load, too much fuel was being pumped into the cylinders and engine would run rough. When more load was applied and more fuel was needed, the other four cylinders kicked in and the engine ran on all eight. Many of the 1468’s and 1568’s had this feature disabled by their owners and their engines fired on all eight cylinders all the time.
From the clutch rearward, the 1468 used the 1466 drive train and final drive. This was larger and heavier than the other models of the 66 series when they were introduced in 1971. The larger final drive gears, bearings, shafts, brakes, ect. were needed to handle the extra horsepower of these tractors.
The list of standard and optional equipment for the 1468 was nearly identical to the 1466. A wide variety of tire sizes and wheel rim combinations along with a two-door enclosed opera-tors cab with heat-A/C, hydraulic seat suspension, two-post or four-post R.O.P.S. were all available to customize your 1468 to fit your exact needs.
The 1468 sold fairly well for IH with over 2900 of them being made from 1971 to 1974.
The 1468 was retired in 1974 and replaced with the new model 1568 V-8 diesel. The 1568 shared the same 3-speed transmission and planetary final drive that its newly announced 6-cylinder engine counterpart (model 1566) had. The 1568 also had the idle on four-cylinders feature like the 1468. The model 1568 was also designed in the very late 1960’s with a prototype tractor being seen in 1971 at IH’s Hinsdale Engineering Center’s back lot. It wasn’t until 1974 when both the
iH built only 862 of the 1568 V-8’s.
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SUPER
Farm Power
photos by
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tractors fuel screw was “turned up” and the race to make big horsepower was on.
The design of the engine’s lower end (crankshaft main bearing caps and the engine connecting rods) would fail from the added stress of turbo charging, usually tossing a rod thru the side of the block. Sometimes if you were lucky, only the cylinder bore was damaged and a dry repair sleeve could be installed. This author
had one such repair done to a 1468 that “saved” it and its still farming yet today.
Many 1468s & 1568s were also saved from the scrap yard by replacing the DV-550 engine with a DT-436 IH built 6-cylinder turbocharged in-line diesel engine, like the 1466 or 1566 used. The frame rails were switched as was the fan shroud and radiators to accommodate the 6-cylinder engine.
1566 and 1568 were finally engineered, tested and ready to build and sell to the farmer.
The 15 series tractors uses a planetary gear final drive and have internally mounted wet brakes. IH only built this series of tractors with a 3-speed (6 speed if equipped with T/A) gear box. You can not take the 4-speed gear box from say a 1066 or 1466 and mate it to the planetary style rear end like the 15 series has. They are not compatible.
The 1568 did not sell as well as the 1468 for 2 reasons. First, it was only built for three years (1974-1976). Second, since it shared the same 3-speed transmission as the 1566, its field working gear selection was limited vs. the 4-speed transmission offered in other IH tractors at the time. This may not seem like much, but in some tillage operations, it mat-tered allot. You either went too slow or too fast even if you had a Torque Amplifier.
IH built only 862 of the 1568 V-8’s. They were loos-ing their sales appeal and the IH built V-8 engines now were being installed only in IH’s large frame 4-wheel drives built by STEIGER. The V-8 diesel engine in those tractors was also an ex-truck division product, the V-800. Watch for more information on these tractors in a future issue of Heritage Iron.
In the 1976 model year IH converted the 66 series to the new “black stripe” decal version. These tractors were painted nearly all IH 2150 red with a black “hockey stick” stripe on the side of their hoods. These tractors were first shown in the fall of 1975 at the Farm Progress Show. They were actually built using many of the components that IH would be using in their forthcoming Pro-Ag line of trac-
tors, the new IH 86 series. IH built only 118 of the 1568 black stripe models and they are very, very hard to find now.
The torque reserve of any V-8 engine is not very good when compared to the design of an in-line engine. An in-line design engine can create more torque at lower engine speeds. V-type engines are made to run fast and have not much low-end torque. Speed and torque are polar opposites of each other. As engine rpm increase from an idle to rated rpm, torque rise increases for a bit then sharply decreases as the engine speed continues to increase. The 68 series V-8 tractors ran best when they were run wide open and not lugged down under heavy load.
Today, both the 1468 and 1568 are highly sought after because of their relative rarity to find and the fact they look like a hot rod muscle tractor. The IH 68 series can be put into the “hot rod like” tractor category, much like the 2255 Oliver and Massey-Ferguson 1155 do be-cause of their V-8 engines. The one item that sets the IH 68 se-ries apart from the other brands is that they have dual exhaust mufflers/stacks, which the others do not. Many of the 1468 and 1568’s being restored are having their cabs removed and fenders R.O.P.S. / canopy installed in their place.
The aftermarket companies did not forget the IH 68 series in any way. The M&W Com-pany (see HI issue # 3) built a twin turbocharger setup to fit the 1468 or 1568. Here dual turbos with individual air clean-ers added some extra “boost” to the DV-550 engine. One of the downsides to this was that the DV-550 was not designed to be turbocharged. Often times after being turbocharged, the
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Today there are still a few “1468” or “1568” series tractors running yet, but with a 6-cylin-der engine under the hood. You need to look at the tractor serial number tag to positively identify one. This would be your only identifier to finding its original model origin. The frame rails, radiator and fan shroud would need to be changed back to have the V-8 engine fit again.
Another short line manufac-turer, Thomure Manufacturing
(see HI issue #3) offers chrome plated manifold heat shields and exhaust muffler heat shields for both the 1468 and 1568. They have also built custom exhaust stacks with miter, curved tip, truck cut or straight cut piping. Painted, chromed or stainless steel finishes are also available. If you want to add more even more shine, Thomure also builds a chrome plated front grille. Contact them for more informa-tion on these items.
