1963 Pontiac Tempest a Car Without a Counterpart
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The 1961 to 1963 Pontiac Tempest A Car Without a Counterpart hen Pontiac’s Assistant Chief Engineer John Z. DeLorean addressed the Detroit Section of the Society of Automotive EWngineers on November 11, 1960, he told them about a radical, new small car that Pontiac was introducing. The name of the car was Tempest, and it featured a number of revolutionary technical break- throughs that he detailed for his audience. The title of his presentation was “Pontiac Tempest, a Car Without a Counterpart.” B Y J A M E S M . L U IKE N S lanning for the Tempest had actually begun together by a unique, curved driveshaft. For their remember that GM had not manufactured a 4-cylinder several years earlier when General Motors engine, they chose to cut the highly-proven Pontiac equipped car since 1928. The last,volume American Pdecreed that its Buick, Olds, and Pontiac divi- 389 cid V8 engine in half, using the right bank of car to use a 4-cylinder engine prior to the Tempest was sions were going to develop a line of senior compact the V8 to create a new 194.5 cid 4-cylinder engine the 1931 Ford Model A, and the last American car with cars for the 1961 model year. While Buick and Olds that utilized many V8 components. It is important to a 4-cylinder engine, period, was the Henry J of 1954. It took a relatively safe path and broke no new ground beyond a small-displacement V8 engine constructed of aluminum by Buick, Pontiac chose to throw con- ventionality out the window and design a radical, new small car that stretched the boundaries of originality and technology in nearly every direction. The design brief for the new, small Pontiac was that the car had to be able to carry six people comfortably with their luggage, provide the ride and handling of a large car, deliver outstanding fuel economy with lively performance, and provide exceptional value with clean styling. While some of these attributes seemed to be at odds with each other, the Pontiac team, led by General Manager S.E. “Bunkie” Knudsen, Chief Engineer E.M. “Pete” Estes and Assistant Chief Above: Starting in 1910 Giuseppe Merosi headed design for Alfa and after the war for Alfa Romeo. Below: Engineer DeLorean, set to work. It would be hard to In 1921’s Targa Florio, Giuseppe Campari was third in this much-modified Type 40-60 Alfa Romeo. imagine another time in the history of General Motors when this much creativity and leadership was massed Above: The Tempest four-door sedan was one of just two models available at introduction and handily outsold in one place at one time. the companion four- door station wagon model. The split grille styling theme, which Pontiac first introduced in 1959, was carried over to the Tempest models. Below: In order to highlight the new Tempest’s revolutionary Eventually, Pontiac settled on a front-engine car drive train, Pontiac released complete tech info, drawings, and photos of the new Tempest’s power train to the with a rear-wheel-drive transaxle that was to be tied media three weeks before they ever revealed the complete car. was against this backdrop that Pontiac strode forward confidently with their plans. In addition to having the advantage of using a proven engine design, the new four offered many cost-saving advantages as well. Of the 44 major components that made up the new 4-cylinder engine, 28 were able to be carried over unmodified from the V8, five were modi- fied slightly, and only 11 were totally different. Pontiac would offer the 4-cylinder powerplant in five different guises from 110 to 155 hp depending on transmission and carburetion selected. Interestingly, the 155 hpver- sion had more horsepower and greater torque than any production 4-cylinder in the world. In fact, it even had more horsepower than any American 6-cylinder engine available at the time as well. Equally unusual was the rear-mounted transaxle. Although other cars, including the Corvair, had a rear-mounted transaxle, they were rear-engined cars. No one had ever paired a front engine location with a rear transaxle. The transaxle was available in manual or automatic versions. The automatic was the most unusual, employing a split-torque principle. In low gear, all power went to the air-cooled torque converter, positioned behind the differential, and then to the transmission. In high gear, 55 percent of the power went to the torque converter and 45 percent went directly to the pinion gear. The split-torque principle offered greater efficiency while cutting power-wasting and gas-eating slippage. The overall result was improved downhill braking, a more solid feel at highway speeds, and a slight increase in mileage. Additionally, the varying ratio of the torque converter was still available for passing. As unique as the engine and transmission were, neither could hold a candle to the Tempest’s unusual, curved driveshaft. The “rope driveshaft” was so named because it sagged 10 3/4 degrees, or 3 inches, over its 7-foot length. The 3-inch curve of the shaft eliminated These 3/4 front and rear views show just what a clean and handsome styling job had been done on the the natural tendency of a long rod to whip and create Tempest Wagon. Nowhere does it give clue that something so completely unconventional is going on under its skin. The Tempest line grew in the spring of 1961 when a snappy two-door coupe was added to the previously available four-door sedan and station wagon models. vibrations. The shaft rode in two ball bearings, which turned. Most amazing was its size. Automatic trans- as a whole, the revolutionary driveline delivered a were placed at the one-third and two-thirds positions mission cars got a 5/8-inch driveshaft, while manual number of benefits. It provided nearly 50/50 weight of the shaft, and was bolted to the engine with six transmission cars received a 3/4-inch version. Both distribution, depending on engine and transmission bolts, with a splined flange used at the rear. In order to sizes were referred to as “thumb-sized” and were choice, and reduced the traditional transmission hump accommodate this shaft, the engine had a downward much smaller than the typical 2 1/4-inch driveshafts to a tunnel that was a mere 2 inches high in the front tilt of 5 degrees to the rear, and the nose of the differ- of the day. Because the Tempest’s shafts were only seat and 3 1/2 inches high in the rear seat. ential had a similar downward forward tilt. Thanks to turning at engine rpm, they did not have to be larger in After creating such a unique driveline, all that was this arrangement, no u-joints were needed anywhere. size to accept multiplied engine torque that had gone left to do was test it and sell it. Some of the testing The shaft was placed in tension by arching it through gear multiplication in a transmission. was done in full-size Pontiacs with the driveline tucked slightly, thus making it able to absorb the torsional Forged from 8660 triple-alloy steel, the curved underneath. In fact, Pontiac was the most frequent user vibrations of the 4-cylinder engine. The amazing shaft driveshaft was then heat-treated and shot-peened as of the GM Proving Grounds during this period. By the also twisted up to 30 degrees, much like a torsion bar well as coated to provide protection from flying stones time the vehicle was ready for market, Pontiac engi- would. This aided in damping the 4-cylinder engine’s and debris. In all, 22 different steps were performed neers had amassed more than 2.6 million test miles to vibrations. In fact, during prototype testing, the drive- after forging the shaft and before its installation. The verify the dependability of its revolutionary driveline. shafts were ordered in pairs and identified as torsion shaft rode in a hollow, upside-down, u-shaped channel In one last test, a new Tempest Sedan and Wagon were bars. Pontiac’s hope was that this subterfuge would dis- that joined the front and rear ends. A flat, pressed-steel turned over to six teenagers, who drove them around guise what they were really creating. The ruse worked, strip was spot-welded to the bottom of the tube to the clock in a 107-day marathon from July 1 to Oct. 15, and several news outlets leaked that Pontiac’s new encase the driveshaft. 1960, covering all 48 contiguous U.S. States and seven small car would have torsion-bar suspension. It was this unique channel that allowed the Tempest Canadian provinces. The results were very encourag- The curved shaft raised the natural vibration fre- to ride down the same assembly line as big Pontiacs ing, with each car only needing minor services and no quency above the highest speed at which the shaft and not a custom assembly line like the Corvair. Taken service or repairs to the unique driveline at all. F.F. Kimpner, another GM executive, was very forth- right in his address to the SAE on the Tempest driveline. He said, “When a new device is offered in competition versus a well-tried and proven one, the burden of proof is on the newcomer. The newcomer must start at, or above, the level its competition has reached.” No less than Mercedes-Benz was so dubious that such a drive- shaft would work that it built its own version.