Mazda embraced the revolutionary rotary
As the Japanese automobile industry began to blossom in the 1960s, it was ready to start demonstrating its engineering prowess.
Honda produced its first car in 1962, the S360/S500/S800, a little roadster strongly influenced by motorcycle technology, right down to its roller-bearing crankshaft and chain-driven rear wheels. This was not surprising from the world’s largest motorcycle manufacturer.
Not to be left out, Toyota introduced the technically advanced 2000GT in 1965 with a doubleoverhead-cam six-cylinder engine producing 150 horsepower from just two litres, excellent for that time.
Toyo Kogyo, Mazda’s parent company, had had little meaningful automobile production before the Second World War, and after the war started modestly with a tiny 360-cc microcar launched in 1960. But Mazda was advancing quickly, and also wanted to enter the high-tech fray.
In 1961, Toyo Kogyo, along with several other companies, purchased a licence for the Wankel rotary engine that had been developed to a practical stage by its inventor, Dr. Felix Wankel, working with Germany’s NSU company in the late 1950s.
Mazda immediately launched its own rotary development program, which would gradually diverge from the NSU design.
The Wankel used a triangular rotor revolving eccentrically inside a housing shaped like a fat figure eight. The rotor produced expanding and contacting spaces between the rotor and housing, and these changing volumes created the intake, compression, power and exhaust phases of the four-stroke engine. There were three rotary surfaces, so one rotor was equivalent to a threecylinder engine. Rotors could be added to increase displacement and power.
Power came from an output shaft rotated by the rotor. Unlike a piston engine, the motion was all rotary.
NSU was the first manufacturer to introduce a Wankelpowered car, its NSU Wankel Spider two-seater roadster. It had a one-rotor Wankel engine and was shown at the 1963 Frankfurt Motor Show. Production started in 1964.
Toyo Kogyo introduced its second rotary-powered car, a prototype Mazda Cosmo sports car, at the Tokyo Motor Show in 1964. Production began in 1967. Its two-rotor, front-mounted Wankel sent power to the rear wheels through a four-speed manual transmission.
The Cosmo coupe was a stylish and sleek departure for Mazda. At only 1,168 millimetres high and 4,140 mm long, it was about the size of the contemporary English Austin-Healey.
The Cosmo’s rotary had two rotors, and although calculating the displacement was tricky, it was set at 982 cc. It produced 108 horsepower, outstanding for a 1.0-litre engine, particularly one weighing just 102 kilograms.
Suspension was by A-arms and coil springs in front and a de Dion axle (dead axle with universal-jointed drive axles) with leaf springs and trailing arms at the rear. Brakes were front discs and rear drums, and steering was by rack-and-pinion.
Performance of the Cosmo was about equivalent to a 2.0litre piston-engine car. In a retro test conducted in June 1993, Car and Driver reported zero to 100 km/h in 8.8 seconds and a top speed of 167 km/h.
The testers confirmed the rotary engine’s characteristic lack of low-speed torque. The outstanding feature was its utter smoothness, tempting drivers to rev far beyond the recommended 7,000-rpm redline.
After about 340 of the first Cosmos were produced, the model was replaced in mid-1968 by a revised edition with the wheelbase lengthened by 150 mm to 2,347 mm and engine horsepower increased by 20 to 128.
When production of this revised Cosmo stopped in 1972, 1,176 of them had been built, for a total of 1,516 first- and secondgeneration Cosmos.
Mazda started importing cars to North America with 1970 models, but the Cosmo was never officially imported, although a few found their way in.
The Cosmo name was revived in 1976 in a 2+2 rotary-powered coupe, but it lacked the style and panache of the original.
Mazda was the only auto manufacturer to stay with the rotary engine. Unfortunately for Mazda in the 1970s, fuel economy and emissions concerns were rising, and the rotary was considered a thirsty engine for its size, although not for its power. This, and its tendency to produce dirtier exhaust, forced Mazda to gradually switch most of its cars to piston engines during the 1970s.
But Mazda never abandoned the rotary, particularly engineer Kenichi Yamamoto, who doggedly persisted with the improvement of the rotary. It developed into a durable, powerful, high-tech powerplant that met current emission standards, and ultimately proved its durability when a four-rotor Mazda won the prestigious 1991 Le Mans 24-hour race.
The rotary was offered in the Mazda’s RX-7 sports car, followed by the RX-8, which was discontinued in 2011 due to slow sales.