Tractor Talk: Allis-Chalmers 8070, End of The Line

By the time 1985 rolled around, the agricultural side of Allis-Chalmers was 71 years old and the company was drowning in debt in the face of a faltering economy. Executives were selling off parts of the company and consolidating as much as possible, but the writing was on the wall. In May, the sale of the Ag side to Klöckner-Humboldt-Deutz (KHD) of Germany was finalized, forming a new company called Deutz-Allis. The factory was to operate through 1985, producing most of the Allis-Chalmers line rebadged as Deutz-Allis tractors. It was a sad time for the city of West Allis, Wisconsin, and a whole lot of workers. What remained of Allis-Chalmers had plans to get back into manufacturing in some fashion at some point, but that was not to be. Now, we need to turn back a few pages.

The late 1970s and early 1980s had been good years for Allis-Chalmers and several new lines emerged. One of them was the big 8000 series: the 8010 (107 hp), 8030 (134 hp), 8050 (152 hp) and 8070 (171 hp). They were the biggest tractors in the line except for the articulated 8550 models. The 8000 tractors were a logical successor to the 7000 line and upped the ante in just about every way, from styling to performance. They were introduced for 1982 and offered under the AC 8070 name to the KHD changeover and then as the Deutz-Allis 8070, which were tractors built in the West Allis plant, but sold as late as 1988. All versions of the 8070 were offered in rear drive or with front wheel assist. The front wheel assist made this a very capable heavy tillage tractor.

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The 670I in the 8070 was a highly evolved diesel at the end of its production run. It was originally developed for the 1963 D21 as the D3400 and underwent many upgrades from there. The first was an upgrade to turbocharging and a new designation, D3500, and a boost in power from 103 to 127 PTO horsepower. The Mark II engines came around 1973 with serious internal and external upgrades to accommodate flywheel power ratings of more than 220 hp. Minor tweaking continued to improve power and durability to the end of tractor production. It was a seven-main bearing, direct-injected engine with wet sleeves. The injection pumps used included Roosa Master, Simms, Bosch and AMBAC, the last of which is the pump on this late-model engine. — The 670I in the 8070 was a highly evolved diesel at the end of its production run. It was originally developed for the 1963 D21 as the D3400 and underwent many upgrades from there. The first was an upgrade to turbocharging and a new designation, D3500, and a boost in power from 103 to 127 PTO horsepower. The Mark II engines came around 1973 with serious internal and external upgrades to accommodate flywheel power ratings of more than 220 hp. Minor tweaking continued to improve power and durability to the end of tractor production. It was a seven-main bearing, direct-injected engine with wet sleeves. The injection pumps used included Roosa Master, Simms, Bosch, and AMBAC, the last of which is the pump on this late-model engine.

The 8070 was powered by the AC 670 series engine, specifically known as the 670I. Displacing 426 cubic inches, its ancestor dated back to the 1963 introduction of the D21. At that time, it was a “clean-sheet” engine design and started out in NA form, but had been turbocharged by 1965. It went on to power a lot of AC tractors and was a staple as a stationary engine and various other industrial uses. By the time the engine made it to the 8070, the AC 426-cid diesel was highly evolved. The 670I was optionally backed up by a six-speed gearbox with a two-speed range box and a full power shift in the six gears or a standard five-speed gearbox with a two-speed range box and a partial power shift (high/low in each gear).

Besides being at the top of their form mechanically, the 8000 series tractors were considered “lookers” and the Persian Orange and black paint, with white wheels, made for a nice-looking tractor. A full cab with two doors was standard and it was claimed the new cabs were 38 percent larger than previous and with nearly 40 percent more glass area. Cab filters kept the air clean and A/C kept it cool. A newly designed seat suspension kept the operator away from the chiropractor more often than previously. The control layout was brought into the modern era and the layout is still very fresh in appearance.

The business end shows the Category II/III three-point hitch, drawbar and dual hydraulic outlets.

The 8070 was among the last of a long line of Allis-Chalmers tractors that were rabidly popular in some parts of the country. AC was never at the top of the sales game, but always managed to field quality tractors in the top tier. The why and how of their demise has frustrated AC fans for decades, but judging by the 8070, they can at least take heart that the company went out with strong products. Only 2,354 of these tractors were built. DW