Mazda Cosmo Coupe. Photo courtesy Mazda.
At the dawn of the 1960s, Mazda was a little-known Japanese manufacturer of light-duty trucks, with a single urban commuter car (the R-360) to its credit. Like other Japanese automakers of the day, Mazda had great ambitions for its future, and it saw the Felix Wankel-developed rotary engine as the distinction it needed to rise above the rest of its Japanese competition. Just as the rotary engine was seen as bold and futuristic for its promise of performance in a compact, lightweight package, no ordinary car would do to introduce the Mazda name to a global audience. Looking for maximum impact, Mazda debuted its own version of the two-rotor Wankel engine in a futuristic sport coupe that seemed to blend the best of styling from both Europe and Japan. Calling its new car the Cosmo, Mazda forever cemented its reputation as a manufacturer of cars for those eschewing the shortest route between two points in favor of the most entertaining.
In the late 1950s, Felix Wankel’s innovative design for an entirely new internal combustion engine seemed to hold far more promise than the antiquated and inefficient piston engine. The rotary engine was able to produce impressive power from a much smaller and lighter package than traditional piston engines, and held the further advantage of having fewer moving parts to fail. Eventually, rotary engines became known for their smooth running and stratospheric redlines, though these benefits were not without offsetting drawbacks. In February of 1961, Mazda’s parent, Toyo Kogyo, became the fourth licensee of the Wankel engine from the patent holder, German automaker NSU.
Photo courtesy Basil McLaren.
Mazda’s work on the rotary engine began immediately after it had licensed the rights from NSU, and before delivery of the first NSU-branded engine even took place. By July of 1963, the company had completed two prototype 798cc Type 8A engines to begin testing, and for the 1964 Tokyo Motor Show company president Tsuneji Matsuda drove the first Cosmo prototype (now with an improved 982cc 10A engine) onto the show stand.
Still, problems with Mazda’s enhanced rotary engine design persisted. Apex seals, positioned at the tip of each rotor’s three lobes, wore quickly, causing the engine to lose compression (and hence, power) while increasing oil consumption and boosting noxious emissions. To solve this problem, Mazda’s engineers developed apex seals that used both carbon and aluminum in their construction, which proved to be far more durable than the previous hollow cast-iron design. In total, some 80 prototypes were built using the improved apex seal design, and the bulk of these (75 percent) were shipped to Mazda dealers as evaluation units. This allowed Mazda to generate a large amount of “real time” data on the engines in a fairly short period of time, and by the close of 1966 the design of the two-rotor, 982cc 0810 rotary engine was finalized. It would come to market producing some 110 horsepower, enough to get the lightweight Cosmo through the quarter mile in 16.4 seconds.
Production of the Cosmo coupes began in May of 1967, and the car featured far more than just a revolutionary engine wrapped in sensuous sheetmetal. Mazda was intent on using the Cosmo as a halo car, and each came with disc front brakes (coupled with rear drums), an independent front suspension featuring an anti-roll bar and an aircraft-themed instrument display that included a speedometer, tachometer, oil pressure gauge, water temperature gauge, amperage gauge and clock. Less than 350 examples of the Series I Cosmo were built before Mazda introduced the Series II car in July of 1968.
Series II Cosmo models built on the lessons learned from the Series I cars, and included such improvements as a more powerful (and less expensive) 0813 rotary engine, now rated at 128 horsepower and 103-lbs.ft. of torque; larger wheels (15-inch, versus 14-inch on the original models); a five-speed transmission (versus the original’s four-speed); power brakes (still with discs up front and drums in the rear); a longer wheelbase for improved ride quality and better interior room and a larger grille area for improved cooling and more distinctive styling. The Series I’s live rear axle and rear leaf springs were retained, but the improved Cosmos shaved 0.6 seconds off the original’s quarter-mile time, while boosting top speed from 115 MPH to 120 MPH.
Mazda constructed 1,176 Series II Cosmos models, but only six were known to have been imported into the United States. While that’s hardly a significant number, even for a low-volume manufacturer like Mazda, it did pave the way for later Mazda rotary-engined automobiles like the RX-2, RX-3, RX-4 and RX-7. In fact, as automakers like Mercedes-Benz, General Motors, Toyota and Rolls-Royce were beginning to abandon the idea of a rotary-powered future, Mazda stuck with its compact and (relatively) powerful engine, evolving it from the 0813 to the 12A, 12B and eventually the 13B and its many variants (including the complex but powerful turbocharged 13B-REW, as found in the last Mazda RX-7 sold in the United States). Mazda’s 13B-MSP Renesis engine, as used in the Mazda RX-8, has the distinction of being the final production rotary engine built by Mazda, though word is that Mazda is still pursuing the design of an improved rotary engine that blends improved torque with better fuel efficiency and reduced emissions.
Though the rotary engine’s thirsty nature and relatively low torque output make it suboptimal for use in mainstream production cars (and only somewhat suitable for use in sports cars), its compact nature and adaptability for multi-fuel use may someday make it the engine of choice for use in series hybrid automobiles (like the Chevy Volt), where an internal combustion engine is used to power a generator, providing electricity to power the electric drive and recharge onboard storage batteries. While both the Mazda Cosmo and the Mazda rotary engine may be out of production (at least temporarily), the engineering effort expended by Mazda on rotary engine design may once again pay dividends, helping to power hybrid-electric cars of tomorrow.