In 1960, the American Big Three (General Motors, Ford and Chrysler) brought out compact cars to counter the increasing market penetration of small imports led by the German Volkswagen.
Ford鈥檚 was the straightforward, no-frills Falcon, Chrysler鈥檚 was the Valiant with its unusual slant-six engine, and Chevrolet鈥檚 Corvair was the most daring with a Volkswagen-influenced air-cooled, rear-mounted, flat-six engine, not a four like the VW.
Other GM divisions also wanted to get in on the smaller-car movement, so they borrowed some of the Corvair鈥檚 internal sheet metal body parts to develop their own slightly larger 鈥渟enior compacts.鈥�
The results were the 1961 Buick Special, Oldsmobile F-85 and Pontiac Tempest. Each had its own divisional styling and engineering cues, but the most technically daring was the Tempest.
For its powerplant, Pontiac created a four cylinder engine by simply cutting one bank off its 6.4-litre (389 cu in.) V-8 to create a 3.2-litre (194.5 cu in.) slant four. To reduce the big four鈥檚 roughness, Pontiac engineers used extra-soft engine mounts reminiscent of Plymouth鈥檚 1931 鈥淔loating Power鈥� system.
Pontiac鈥檚 half-an-eight not only reduced engine development time and expense, it kept production costs lower because the four could pass down the same engine assembly line as the eight.
Pontiac鈥檚 driveline was also very unusual for an American car. Although the engine was in the front, the transmission was in a unit with the differential, known as a transaxle.
Power went to the transaxle via a flexible, one-piece, 2,134-millimetre-long, 16.5-mm-diameter steel driveshaft that 鈥渟agged鈥� in the middle, earning the Tempest its 鈥淩ope-Drive鈥� nickname.
It was supported along the way by two steady-bearings and ran in its constantly curved condition so no universal joints were required. It also acted like a torsion bar to further dampen out some of the engine vibration from the big four. Rear suspension was independent, with swing axles and coil springs similar in design to the Corvair鈥檚.
The Tempest came with a three-speed manual transmission or two-speed 鈥淭empestorque鈥� automatic with a torque converter. The automatic had a novel feature: when the transmission was in high gear, 60 per cent of the power was routed through the torque converter and 40 per cent through non-slip mechanical gears. This split-torque contributed to better fuel economy by eliminating some of the slippage inherent in automatics, a problem later solved with a lock-up torque converter.
The four-cylinder engine鈥檚 horsepower ranged from 110 to as high as 166 in an optional high-performance version. There was no transmission hump with the rear-mounted transmission, although it sacrificed a half cubic foot of trunk space. It also brought the car鈥檚 front/rear weight distribution to the desired 50/50.
Pontiac claimed a number of engineering firsts for the Tempest: the first American four-cylinder car engine since the Crosley and Henry J; first American front-engine car with rear automatic transmission; first with a curved driveshaft; and the first split-torque automatic transmission with torque converter.
The four-cylinder Tempest鈥檚 acceleration was the slowest of GM鈥檚 senior compacts. Car Life鈥檚 comparison test of the three 1962 cars in December 1961 reported the 140-horsepower Tempest鈥檚 zero to 100 km/h at 15.9 seconds. The 135-horsepower V-6 Buick took 14.8, and the 155-horsepower Olds V-8 only 14.
The Tempest鈥檚 top speed was also the lowest at 142 km/h, compared with 153 for the Buick and 161聽for the Oldsmobile. But the Tempest did get slightly better fuel economy.
The motoring press was captivated by the Tempest鈥檚 technical novelty and was generous with its praise. Motor Trend magazine gave it its Car of The Year Award.
Alas, the Tempest鈥檚 technical innovation proved more seductive than its real-world performance. The driveshaft had a tendency to vibrate and rattle, the swing axles were prone to the same oversteering tendencies as the Corvair鈥檚, and that big four was a rough runner.
In spite of these shortcomings, the Tempest initially outsold its corporate stalemates, surpassing 100,000 sales in both 1961 and 1962. Then, in 1963, the Buick and Oldsmobile models both topped 100,000 while the Tempest slipped to less than 70,000 in spite of the availability of a 5.3-litre (326聽cu in.) V-8.
For 1964, Pontiac abandoned the curved driveshaft and rear transaxle and reverted to a conventional driveline.
That early Pontiac Tempest was an effort to appeal to those interested in an unconventional and innovative driveline layout and the increased interior space it provided. But the shortcomings outweighed the advantages, and it soon faded into oblivion.
The conventional Tempest that came after the rope-drive model did leave one lasting legacy, though. Its 1964 Le Mans GTO big-engine-in-a-light-car option would spawn the muscle-car era that lasted from 1964 to the early 1970s.
