1972 Mazda Cosmo; photo courtesy Mazda Canada
1972 Mazda Cosmo; photo courtesy Mazda Canada. Click image to enlarge

Story and photo by Bill Vance

As the Japanese automobile industry began to blossom in the 1960s, it was eager to start demonstrating its engineering prowess. Honda as just entering the automobile business with its first car, the S360/S500 roadster, in 1962. Honda was the world’s largest motorcycle manufacturer, and the little roadster was strongly influenced by motorcycle technology, right down to its roller bearing crankshaft and chain drive.

Toyota introduced its technically advanced 2000GT in 1965 with a double overhead cam, six-cylinder engine. It produced 150 horsepower from just two litres, which was excellent output for that time.

Toyo Kogyo, Mazda’s parent company, had not had any meaningful automobile production before the Second World War. After the war it finally got a modest start with a tiny 360-cc car launched in 1960. But Mazda was advancing quickly, and wanted to enter the high-tech fray to prove that it had really arrived.

In 1961 Toyo Kogyo purchased a license to develop and build the Wankel rotary engine that had been brought to a practical stage by Dr. Felix Wankel and Germany’s NSU company in the late 1950s. Several other companies, including General Motors, Curtiss-Wright and American Motors also purchased Wankel licenses. Mazda immediately launched its own rotary development program, which would gradually diverge from the NSU design.

The Wankel, as it was then called, uses a triangular rotor revolving eccentrically inside a housing shaped like a fat figure eight. The rotor’s path produced expanding and contacting spaces between the rotor and the housing wall, and these changing volumes create the four phases – intake, compression, power and exhaust – of the four-stroke engine. Since there are three rotary surfaces, one rotor is equivalent to a three cylinder engine. Power is taken from an output shaft internally geared to the rotor, and unlike a piston engine, the motion is all rotary.

NSU would be the first manufacturer to introduce a Wankel-powered car with the rear-engined NSU Wankel Spider, a small 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 was the second to introduce a rotary powered car. This was the Mazda Cosmo, shown in prototype form at the Tokyo Motor Show in 1964, and put into production in 1967. It had a two-rotor Wankel mounted in the front, driving the rear wheels through a four-speed manual transmission.

The Cosmo coupe was a departure for Mazda, being stylish and sleek and only 1,168 mm (46 in.) tall. At 4,140 mm (163 in.) long, and 1,575 mm (62 in.) wide, it was about the size of the contemporary Austin-Healey.

The rotary used in the Cosmo had two side-by-side rotors, and although calculating the displacement was tricky, it was finally set at 982 cc. It produced 108 horsepower, which was outstanding for a 1.0 litre engine, particularly one weighing only 102 kg (225 lb).

Suspension was by A-arms and coil springs in front, and a de Dion axle with leaf springs and trailing arms at the rear. Brakes were discs in front and drums at the rear, and rack-and-pinion steering was used.

Performance of this 1.0 litre Cosmo was very good, about equivalent to a 2.0-litre piston engined car. In a retro test conducted in June 1993, Car and Drive magazine reported a zero to 96 km/h (60 mph) time of 8.8 seconds, and a top speed of 167 km/h (104 mph).

A characteristic of the rotary engine was a lack of low speed torque, which was confirmed by the testers. The outstanding feature was its utter smoothness, even away beyond the recommended 7,000 rpm redline, which was also the peak horsepower speed.

After some 340 of the original Cosmos were produced, it was discontinued in mid-1968, and replaced by a revised model with the wheelbase lengthened by 150 mm (5.9 in.) to 2,348 mm (92.5 in.) and engine horsepower increased by 20 to 128.

By the time production of this revised Cosmo stopped in 1972, 1,176 of them had been built, for a total of 1,519 of the first generation Cosmo.

Mazda started importing cars to North America with 1970 models, but the Cosmo was never officially imported, although a few did find their way here. One of these, a 1972 model, is owned by Mazda Canada. The Cosmo name was revived in 1976 in a 2-plus-2 rotary powered coupe, but it lacked the panache of the original.

Mazda was the only auto manufacturer to stay with the rotary engine. Unfortunately for Mazda, in the 1970s concerns about fuel economy and emissions were rising, and the rotary was considered a thirsty engine for its size, although not for its power. This, combined with its tendency to have a dirtier exhaust, forced Mazda to gradually switch most of its cars to piston engines during the 1970s, although it never abandoned the rotary.

Mazda, particularly engineer Kenichi Yamamoto, doggedly persisted with the improvement of the rotary, developing it into a durable, powerful, high tech powerplant that meets current emission standards. It is offered here in Mazda’s RX8 sports car, the spiritual descendent of the original 1967-1972 Cosmo.

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