Like most Tractor manufacturers, the Oliver Corporation looked for other venues in which to sell diesel engines. One that kept them pretty close to their agricultural roots were power units. Power units had many uses in industry and agriculture. Primary uses were to run generators, pumps, sawmills, concrete mixers, conveyers, balers, air compressors, hammer mills, hoists, winches… anything that needed power where there was no electricity. They could be adapted to pieces of towed equipment, such as pull-behind combines and to self-powered equipment like surface compactors.

The 188-D was a 231 cubic inch Lanova six with a 3.50 x 4.00-inch bore and stroke and a 15.5 compression ratio. Maximum power was 49 horses at 2000 rpm but continuous power was 44.5 at 1800. Continuous torque was 142 lbs-ft @ 800. This unit was rated for a 19 KW generator (continuous) and to pump 750 GPM. At a peak load at 1300 rpm, this engine used 2.1 gallons per hour.

Oliver started producing diesel power units in 1950 and offered them with their full range of engines; gasoline, LPG and diesel. When they debuted, the primary line of Oliver tractors included the 66, 77, 88 and 99 so the power units corresponded by mounting the engines available in those tractors. To designate them, a “1” was added, so the 166 Power Unit had the same engine as the 66 tractor, for example. Rating varied little and there a few tuning tweaks necessary to suit the application. Besides some standardized units, Oliver offered to custom design for specialized applications.


Oliver had teamed up with Waukesha for many years to build their engines, gas or diesel. They all shared a similar architecture. The diesels were of the Lanova type, even though Waukesha did not use that combustion system. Waukesha used a Ricardo IDI chamber on it’s own diesels but since Oliver had the Lanova license, they produced special engines. The lower ends were very much the same between them, though Waukesha offered a few other variations of bore on stroke on the same architecture that Oliver didn’t use. The special engines were badged “Oliver Diesel” but sometimes are referred to as “Oliver-Waukesha.”

Three Oliver Power units on display, in the foreground the 177-D, next the 188-D and beyond that a 188 gasser (no “-D”). This is more or less how they came from the factory, with a Rockford clutch and a keyed shaft. The far gasser has the extended shaft setup, often used were a pulley drive (flat or v-belt) was to be installed. The 177 has the optional 20 gallon fuel tank, while the 188 was designed for a remote tank. All these diesel sued a Bosch PSB pump. They were used with or without side covers.

Starting in 1954, the Super Series 66, 77, 88 and 99 tractors debuted. The Power units carried the same designations, e.g. Super 166, Super 188, etc. As it related to the engines, the Super designation came with increased power outputs. The power boost came from bore increases, which was across the board, except for the 199. Tuning and sometimes being spun up a few hundred RPM contributed to the increase.

The 177-D was a 194 cubic inch six-cylinder Lanova diesel with the same bore, stroke and compression ratio as the 166-D four but with two extra cylinders. It was rated for 42.5 maximum power at 2000 rpm and 38 continuous horsepower at 1800. Continuous torque was 121 lbs-ft at 800 rpm. You could use this engine to run a 16KW generator or to pump 650 GPM of water. Instrumentation was adequate, with an amp gauge, oil pressure and water temp gauge facing this way and a mechanical tach facing to the rear. Fully loaded fuel economy for the 177-D peaked at about 1300 rpm and it used 1.9 gallons per hour.

The Super 166 got a 0.19-inch bore increase, going from 129 to 144 cubic inches. With that and spinning it up to 2000 rpm on the continuous ratings, it jumped from 27 to 37 maximum horses, and 24 to 29.8 continuous horsepower. The 177 got the same bore increase and rpm increase, jumping from 194 to 216 cubic inches, and going from 42.5 maximum horses to 49.5 (38 to 41 horsepower continuous). The 188 got a whopping quarter-inch bore increase to go from 231 to 265 cubic inches. Max power jumped from 49 to 60 horses and continuous from 44.5 to 49. The 199-D kept its original 302 cubic inch displacement and max power rating but by bumping it to 2000 rpm, continuous power went up from 56 to 59. The new rating gave all the Super series slightly higher work ratings in whatever venue they were offered.

The big guy in the ‘50-54 lineup was the 199-D. It was a 302 ci Lanova, with a square 4.0×4.0-inch bore and stroke and a 15.5:1 compression ratio. It cranked out 73 horses at 2000 rpm max and 56 at 1800 continuous. It was rated for a 28.5 KW generator or to pump 1,100 GPM. Torque was 203 lbs-ft at 1000 rpm continuous. The 99 Series diesel tractor it corresponded with was only built for a couple of years in ‘53 and ‘54.


In 1957, a fifth diesel was added to the power unit lineup, the Super 225. This unit differed in that it used a Hercules DD-339, which was a direct-injected diesel and part of a new line of DI engines from Hercules. Hercules produced a DD series power unit as well and it’s likely the Oliver was a rebadged version. From the few pictures we’ve seen, the tin may have differed between the Hercules and Oliver units.

The 166-D (“D” for diesel) was a 129 cubic inch, four-cylinder Lanova diesel with a 3.31 x 3.75-inch bore and stroke, a 15.5:1 compression ratio, producing 27 maximum horsepower at 2000 rpm (24 @ 1800 continuous). Torque output was 80 lbs-ft @ 800 rpm continuous. This engine had the power to run a continuously rated 10KW generator or push a 400 GPM pump.

The Oliver power units were offered through 1960 and then discontinued. The most likely reason for that is Oliver’s tough financial situation and being purchased that year by White Motor Company. White would soon purchase Hercules as well so the power unit part of Oliver’s operation became redundant. White would go on to purchase, and eventually consolidate, Oliver and Cockshutt. White would develop it’s own brand of tractor, face trouble and be folded into what is now AGCO. That’s for another article.

We couldn’t find a picture of a Super 225 power unit but did find this image of a Hercules DD-339 direct injected engine. It had a 4 x 4.5-inch bore and stroke and an 18:1 compression ratio. It had a 130 hp at 2800 rpm maximum rating, 100 hp at 2000 continuous. It’s shown here with a Roosa-Master pump but they also used Bosch pumps. This bare engine weighed in at 750 pounds.

The restored engines shown here were shot at the 2017 Portland Tri-State Antique Engine and Tractor Show. That year they were celebrating Oliver but we weren’t able to find the owner of these superbly restored Oliver power units. Restoring and collecting vintage power units has become a growing hobby in and of itself, but tractor collectors have long added complementary power units to broaden their collections.

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