The Oliver 1550 and 1555

OLIVER 1550 AND 1555

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OK, the 1550 was the second-smallest domestically built Oliver in the mid-1960s, but the 1555 was the smallest domestically built Oliver in the first half of the ’70s. The funny thing is, they weren’t really “small” tractors at all.

What’s interesting to note is that the 1550 was a direct descendant of one of Oliver’s most popular tractors, the 77 and Super 77 series, which had been built from 1948 to ’58 before evolving into the 770 in ’58. Even more fascinating is that the similar 77 and 88 series tractors had once been Oliver’s “big” tractors, but by the time the 1550 debuted for 1966, it had moved to the opposite end of the line—and it was still a six-cylinder tractor, no less! Starting in 1960, the White Motor Company began buying ag product manufacturers. Oliver was the first and became the cornerstone of a new ag manufacturing powerhouse. White soon acquired Cockshutt and Minneapolis-moline and began centralizing and homogenizing the technology while maintaining the brands. By the time the 1550 came around, the smallest Olivers were now coming from overseas—first from David Brown in England and later from Fiat of Italy.

Although it had been restyled and updated, the 1550 was a bit dated. Even so, it was still a popular utility-sized tractor, and it had an unbeatable reputation. The 50 series tractors were an update of the so-called “Thousand Series” that had debuted for 1960 in the form of the 1800 and 1900 to start; and later,

the 1600. The 50 series added new styling, a few features and power output upgrades across the line.

The 1650 diesel had debuted in ’64 with a 284ci, sixcylinder diesel rated for 66 PTO hp, but the Oliver sales department reckoned a lower-cost tractor in this general size range was needed to flesh out the line and replace the old—but popular—770.

With a downgrade to a 232ci diesel (which tested out to 53.5 PTO hp in Nebraska Tractor Test 943), voilà!—the 1550 was born. It had the advantage of being a few steps above the 48 PTO hp 770 and its smaller, 216ci diesel.

The 1550 had many advantages for farmers who needed a tractor in its power range. First, it was built on a final drive designed for more power, and that final drive had many proven, reliable years behind it. Standard was the six-speed spur gear trans, but Hydra-power Drive was an option. Hydra-power was a self-contained, two-speed splitter that could be used in any gear. There were many such devices on the market at that time, but Oliver made one of the better and more reliable ones.

The 1550 could be ordered as a Rowcrop with adjustable-tread rear wheels and either a dual- or single-wheel narrow front axle or an adjustable-width wide front axle. A variation of the Rowcrop wide front was a high-clearance model. A Utility with a

set-back adjustable front axle was listed, along with Wheatland or Riceland versions with a heavy, fixed front axle. The 1550 was built through 1969 until being replaced by the 1555 in late 1969 for the ’70 model year.

The 55 Series

By 1970, the Cockshutts had long since morphed into rebadged Olivers, and, gradually, so had Minneapolis-moline. Not many knew it at the time, but plans were afoot to consolidate the entire ag lineup under White badging. Well, maybe that wasn’t too surprising, because the tractors had begun to have a “White” emblem affixed and came to be known as White-oliver tractors. Still, updates were needed, and the 55 series was born.

For the 1550 models, that extra fiver didn’t amount to much. Mainly, it boiled down to styling and badging changes. The lineup remained the same—rowcrop, Utility, High Clearance, Wheatland and Riceland. Even though Oliver would develop a three-speed auxiliary gearbox (the Hydraul-shift), it would not be used on the 1555, which retained the optional two-speed Hydra-power.

The 1555 would soldier along through 1975; and, by then, the model line transition from the Oliver identity to the White would be largely complete.

Some Oliver tractors would make the transition to be restyled and rebadged as Whites, but the 1555 wasn’t one of them—at least not directly. The White 2-70 replaced the 1555 and 1655 models. Because the 1555 and 1655 were still very similar, differing mainly in engine size and power, the 2-70 could still be said to be a descendant of the 1550 and 1555 models.

The White 2-70 would continue into 1982. White, itself, would become part of AGCO in 1991, adding its remaining heft to that now-powerhouse stable of farm equipment.

Power for both the 1550 and 1555 came from a 232ci Oliver-waukesha six. Waukesha had its own IDI combustion chamber that dated back to 1946 but built the Oliver engines with Lanova heads (because Oliver had a license). Oliver had used a few Buda-lanova engines in the past and evidently liked them. The heads were cast in the Oliver foundry but were machined and assembled by Waukesha. The blocks were a Waukesha design that was a wet-sleeved, four-main engine that shared architecture with a gas engine of the same displacement. The 232 was essentially a big-bore version of the 216, which had been in production for many years. The basic design dated to the late 1940s. Although the earlier version of this engine used a Bosch APE pump, by the time the 1550 debuted, they had moved on to the simpler Roosa-master.

There aren’t a lot of differences between the 1970 1555 in the foreground and John Parker’s 1965 in the background. The striping is different, and the 1555 has headlights protruding from the grille, while the 1550 has the lights only in the fenders. Both of these are Utilities with the set-back front axle (which delivered a tighter turning radius). These images were shot at the 2017 National Threshers Association show in Wauseon, Ohio.

Another view of the 1550 (foreground) and 1555, with the grilles showing the main quick-reference visual difference between the two models.

The working ends of the 1550 and 1555 were largely the same (1550 shown). Most came standard with a three-point hitch and 540 rpm PTO, with a dual-range 540/1,000 rpm PTO.

One of the Oliver tractor resources the author trusts is Sherry Schaefer’s book, Classic Oliver Tractors. This is the second edition of a book that has long been source material for those studying the Oliver line. Oliver is in Sherry’s “DNA” because of her father, Oliver Schaefer (that’s really his first name!), who was an Oliver equipment dealer back in the day and still buys and sells tractors and parts.