From 1961 to 1963, the “senior compact” Pontiac Tempest had a novel powertrain layout featuring a front engine and a rear transaxle, connected with an unusual flexible driveshaft known as the “rope drive.”
Introducing the Pontiac Tempest
Although developing the Tempest and getting it ready for production in time was an enormous amount of work, the Pontiac engineers and designers who worked on the project were enthusiastic about it. The Tempest was one of the most technologically interesting models Pontiac had ever offered, and even the challenges it presented were colored with the excitement of doing something new and novel. We assume it was a matter of divisional pride as well; through their efforts, and thanks in no small part to the ingenuity of John DeLorean, they had succeeded in transforming an unwanted corporate hand-me-down into a unique Pontiac product.
When the Tempest made its press debut in early 1960, automotive editors were also very excited about it. Above all, the new Tempest seemed like Progress, a sign, along with the Corvair, that Detroit could offer more than senseless bulk and glitz. The Tempest was sensibly sized and seemed to give away little in technical sophistication to high-end European cars. It was the Motor Trend Car of the Year for 1961, and some reviewers optimistically declared that other automakers would rush to imitate it.
Convincing the public was another matter. The average compact car buyer did not know from transaxles, and the practical advantages of the front-engine/rear-transaxle layout were not always obvious. Yes, the Tempest nominally offered seating for six, but so did most domestic cars in this class, and the manual transmission’s floor shifter might require some tense negotiations with the front middle passenger. Yes, the drivetrain tunnel was lower than usual for a front-engine/rear-wheel-drive car, but the Tempest couldn’t boast a completely flat floor like the Corvair’s. Most gallingly, a four-cylinder Tempest was not substantially less nose-heavy than a Buick Special or Oldsmobile F-85, because the Trophy 4 engine weighed so much more than the aluminum V-8. (The Trophy 4 alone weighed more than the Oldsmobile Rockette V-8 and 61-5 Hydra-Matic transmission put together, and the Buick engine and transmissions were lighter still.)
In its favor, the Trophy 4 engine gave the Tempest peppy acceleration. Even in standard form, with an 8.6:1 compression ratio and a single-barrel carburetor, its gross output was 110 hp (about 82 kW) and a stout 190 lb-ft (258 N-m) of torque, comfortably ahead of the Corvair, Falcon, and Comet. With either transmission, buyers could specify a higher 10.25:1 compression ratio, adding a further 10 hp and 12 lb-ft of torque (about 7 kW and 16 N-m), and cars with the high-compression engine and TempesTorque got a hotter cam that added 20 hp and 5 lb-ft (about 15 kW and 7 N-m). Most interesting from a performance standpoint was the optional high-compression four-barrel version, available only with TempesTorque, which offered 155 hp and 215 lb-ft of torque (equivalent to about 116 kW and 292 N-m). That was enough to make the Tempest a fairly hot number for 1961, and unlike the rare Chrysler Hyper-Pak Slant Six, the Trophy 4 still wasn’t especially high-strung in this form.
With the base low-compression engine, manual shift, and standard 3.55:1 axle ratio, the Tempest could do 0–60 mph (0–97 km/h) in less than 15 seconds — decent for this class — with a top speed of about 92 mph (148 km/h). Adding the high-compression four-speed engine and the optional 3.73:1 axle brought 0–60 mph (0–97 km/h) times below the 12-second mark and allowed a top speed of around 100 mph (160 km/h), brisk for an American family car of the period.
Tempest buyers could also order the same 215 cu. in. (3,528 cc) aluminum V-8 that was standard in the Buick Special, although few customers did so. Initially offered only with a two-barrel carburetor, the V-8 was no more powerful than the four-barrel Trophy 4 and a good deal more expensive (listing for $216 extra), although it was much smoother than the Pontiac 4 and about 35 percent lighter, providing better weight distribution. Pontiac had no great enthusiasm for the aluminum V-8, which was offered mostly at the insistence of corporate management, and proved troublesome as well as expensive. Only 2,004 V-8 Tempests were sold for 1961.
Neither engine was especially thrifty. Although the Tempest had respectable fuel economy for an American compact of its era, even the base four was almost as thirsty as a V-8 F-85 or Special. This shouldn’t have come as a great surprise, considering that a four-cylinder Tempest was heavier than its Oldsmobile or Buick cousins, gave away only about 21 cu. in. (342 cc) to the aluminum V-8, and had considerably more displacement than many (slower) six-cylinder rivals. However, Tempest buyers assumed that a four-cylinder engine would be more parsimonious, and were annoyed to find that it wasn’t.
There were greater disappointments in store for buyers who DID know what a transaxle was and anticipated dynamics resembling a Lancia or other high-end European car. The Tempest’s suspension tuning was typical Detroit, viz., soft and under-damped in the interests of a compliant ride. (Stiffer springs and shocks were theoretically available, but Pontiac didn’t promote them, and they didn’t appear on the standard lists of factory or dealer-installed options for 1961.) As for steering, your choices were light and very slow with unassisted steering, or a bit quicker and really light with power assist. Either way, crisp steering response was not on the menu.
That was perhaps just as well, because the Tempest could be a handful when pushed, betraying its kinship with the cheaper Corvair and some of the compromises Pontiac had had to accept to bring the Y-body compact to market.
The Swing-Axle Follies
When the Tempest debuted, keen observers noted that its rear suspension looked suspiciously like that of the Corvair, despite protestations to the contrary by Pontiac officials. In fact, it was substantially the same suspension: swing axles with semi-trailing lower control arms to carry the rear coils and shock absorbers (which acted against the rear crossmember) and transmit acceleration and braking forces to the body. The Tempest’s front suspension was also Corvair-like, with coil springs and upper and lower control arms, the latter located by a short compression strut between the lower arm and the front crossmember. Like the Corvair, there was initially no anti-roll bar, although one would be added later in production.
As with almost every aspect of the Tempest, the Corvair suspension was specified for cost reasons. Pontiac was aware of its shortcomings — DeLorean actually designed and patented both low-pivot and simulated low-pivot suspensions that would have addressed some of those limitations (U.S. Patent Nos. 2,968,358 and 3,011,578) — but there just wasn’t room in the limited budget for anything else.
Some readers are no doubt familiar with the characteristics of swing axles, but a brief recap seems in order. In a swing-axle suspension, the differential is fixed (in this case, to the rear crossmember), with each axle halfshaft pivoting on a universal joint to allow the halfshaft to transmit power while also acting as a locating arm for the wheel. This has several advantages: A swing-axle suspension has significantly less unsprung weight than a live axle and allows each rear wheel to react independently to bumps, both factors that improve ride quality. However, a swing-axle rear suspension also has a high static roll center (13.6 inches (354.4 mm) above ground level, in the case of the Corvair), which increases the tendency to oversteer, and a short swing arm length, which means that each rear wheel undergoes significant camber changes as it moves up and down through its arc of travel. At certain angles, the axle halfshaft can also act as a lever, forcing the differential upward in an effect known as jacking. This can result in a type of extreme camber loss known as tuck-under, which means what it sounds like it means. On both the Corvair and Tempest, these issues were compounded by rear alignment that gave the rear wheels a bit of static positive camber (wheels tilted outward at the top) when unladen. The expectation was that the weight of rear passengers and cargo would compress the rear springs and give zero camber or slight negative camber, but in a lightly loaded car, the positive camber setting served to further reduce the bite of the rear tires.
The Tempest had at least two advantages over a Corvair with the same suspension: greater width (in particular a 2.8-inch (71-mm) wider track) and significantly less weight over and behind the rear wheels. However, with the same basic geometry as the Corvair, its foibles were similar.
Driven conservatively, the Tempest was docile enough, and its relatively neutral balance could make it feel poised and agile, belying the exaggerated camber angles the wheels assumed in even moderately brisk cornering. As with the Corvair, the problem was not that the Tempest would oversteer, but that the point of departure could arrive with little warning. The more candid contemporary road tests found the Tempest’s cornering limits surprisingly low and warned that catching the tail if it broke loose was not easy, a consequence of the slow steering. In December 1961, Mercedes-Benz engineer Rudolf Uhlenhaut, a driver of great skill, managed to spin and roll (or nearly roll; accounts vary) a Tempest during a demonstration at a press preview for the new Mercedes 300SE in Daytona Beach, Florida, bending a wheel in the process. The Y-body Special and F-85, with their conventional four-link live axles, couldn’t be called agile, but they were far less likely to swap ends.
Another area where the Tempest could provide unwelcome excitement was brakes. All of the Y-body cars had 9-inch (229-mm) drum brakes, but the Tempest’s had 12 percent less swept area than the Y-body Special and F-85 despite its significantly greater curb weight. The brakes faded heavily in hard use and lining life was unimpressive. The parking brakes’ ability to hold the Tempest on a steep grade also left much to be desired, which could give owners of cars with TempesTorque an unhappy reminder that the automatic had no parking pawl.
The Y-Bodies Change Course
The upshot was that for all its cleverness and engineering novelty, the Tempest was not a particularly outstanding entry in the now-crowded domestic compact field, even among its GM Y-body “senior compact” siblings. It was far from the worst of the bunch — it was much quicker than a Falcon or Comet, less eccentrically styled than the Valiant or Lancer, and cheaper than the F-85 or Special. It also had good snow traction and a more usable rear seat than a four-door Corvair. However, the handling limitations of the rear suspension and the uncertainties of the unconventional powertrain kept the Tempest from being seen as a safe choice. Consequently, while the Tempest was the bestseller of the B-O-P senior compacts and the only one whose sales reached six figures in 1961, it wasn’t by much: 1961 production totaled 100,783 units, a disappointing figure by GM standards.
By early 1961, even before the end of the model year, the sense of urgency that had driven the development of the X-100 project had largely faded. Although U.S. auto sales declined about 10 percent from 1960 to 1961, the arrival of the Corvair, Falcon, Valiant, and Studebaker Lark the year before had at least temporarily satisfied most of the American market’s appetite for compact cars. The market penetration of imported cars that had caused so much alarm two or three years earlier was now on the decline, giving U.S. automakers the confidence to resume ignoring the imports for a while longer.
This left the GM mid-price divisions with second thoughts about the entire senior compact program. Although bigger than the Corvair, the Y-body was still smaller than Oldsmobile or Buick were comfortable with; Pontiac proposed further enlarging the body shell as part of the 1963 facelift. None of the divisions was very happy with the NVH characteristics of the unit body, particularly in the area of road noise, which all three cars suffered at higher speeds. Mechanical commonality was considerably less than originally anticipated, which drove up unit costs, and the aluminum V-8 was proving an enormous headache from a manufacturing and service standpoint as well as being inherently expensive to build. Buick had already embarked on a crash program to create a cast iron V-6 from the V-8 design, using the latest “thinwall” casting techniques to keep the weight down, while Pontiac was looking at creating a de-bored and lightened version of its own V-8 to replace the costlier aluminum Buick engine.
Oldsmobile general manager Jack Wolfram and Buick general manager Ed Rollert wondered aloud if it made sense for their divisions to stay in the compact market. The Y-bodies weren’t doing much for the bottom line, and the sales force didn’t seem to know what to do with them. As for Pontiac, the Tempest was bringing in a respectable number of first-time buyers, but its production costs (particularly for the driveshaft, whose machining was costly and which had to be made in several variations that weren’t interchangeable) kept it from being a very profitable venture.
Moreover, by the time the senior compacts entered production, the expectations of the market had shifted. The name of the game was now “Monza,” as in Corvair Monza, the unexpectedly popular sporty version of the Corvair. Introduced late in the 1960 model year, the Monza had become an immediate hit, with its plush trim, bucket seats, and (optional) hotter image transforming the Corvair from bare-bones econobox to low-priced sporty car. For 1961, it gained the option of a fully synchronized four-speed gearbox, and Chevrolet extended the Monza trim series to include four-doors as well as coupes.
The success of the Monza had clearly caught Pontiac, Oldsmobile, and Buick off-guard — even more than it had Chevrolet, which was struggling to keep up with demand. Jack Humbert’s Pontiac design studio had created full-size clays of a Tempest coupe as early as July 1959, but with only four-door sedans and wagons in the initial lineup, the expectation had obviously been that most buyers would be looking for economical family cars to bridge the gap between smaller imports and “Detroit dinosaurs.” A floor shifter and the four-barrel engine might make for an entertaining combination in a Tempest Safari wagon, but it was no Monza.
It took until the New York International Automobile Show in April 1961 for the mid-price divisions to debut their first two-door Y-bodies. In a fit of better-late-than-never overkill, there were actually two different versions of the new body style: a standard coupe with a wide, slightly wrapped backlight and what Pontiac called a “Sports Coupe,” with a smaller rear window and more sharply creased sail panels for what Pontiac dubbed “town-car styling.” The latter, evidently deemed the more elegant or upscale of the two rooflines, was used for now inevitable B-O-P Monza-fighter: the Oldsmobile F-85 Cutlass, the Buick Skylark, and the Pontiac Tempest Custom Coupe.
At the New York show, Pontiac had shown off an upscale Tempest coupe called Le Mans, although unlike the Cutlass and Skylark, it had an extra dose of unrepresentative auto show frosting, including wire wheels, a padded vinyl top, a tachometer mounted on a short under-dash console, and a modified Trophy 4 engine with a GMC supercharger. As far as we’ve been able to verify, Pontiac didn’t apply the Le Mans name to the production Tempest until the start of the 1962 model year, but the late ’61 Custom Coupe had the Sports Coupe roofline and the requisite bucket seats, which were also offered on Custom sedans and Safari wagons. The base coupe had the other roofline and none of the fancy trim, but it assumed the role of price leader, with a list price starting $54 below the sedan and a significant $184 less than the Custom Coupe.
Because of their late introduction, the coupes accounted for only about 15 percent of 1961 Tempest production, with sales split almost equally between the base and Custom trim series. However, the two-door models would be an essential part of the Tempest’s future.