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The first fruit of Mazda's rotary project came surprisingly soon. The company had fielded its first modern production automobile in 1960, with the license from NSU to produce a rotary engine completed only in mid 1961. The COSMO SPORTS, or as it was known in the few countries it was exported as the MAZDA 110S was officially launched on May 30, 1967. This was the world's first twin rotor production car, beating even the NSU Ro80 by three and a half months. Mazda paid NSU hefty license fees for the use of the wankel design. All Mazda rotary motors bare a NSU casted serial number. The start of the Cosmo project was way back in December 1962, with Mazda's first twin rotor engine prototype in July 1963. The first Cosmo prototypes were produced by August 1963, and in October 1963 the head of Mazda, Tsuneji Matsuda drove the prototype (known as "project L402A") to the Tokyo Motor Show. This prototype had a 2 rotor x 398cc prototype engine known as the L8A. Interestingly, this engine used a combination of peripheral porting and side intake porting. resistance and keep the blade from rising off the windshield at high speeds. The first vehicle produced to include this "speed blade" innovation was a Mazda Cosmo produced by Toyo Industries link 
The prototype engines and cars progressed, and in April 1966 a pre-production run of 80 Cosmos were made, 60 of which were sent out as evaluation models to Mazda dealers in Japan, accumulating over 600,000km in 6 months. The engine used was the L10A , with 2 rotors x 491cc and "normal" side intake ports as used in all standard production Mazda rotaries. The peripheral ports were dropped and the engine size increased to give better operating characteristics. The design was finalized in late 1966 and production would have commenced soon after for the May 30, 1967 launch date. |
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The L10A was the designation for both the car's model name the engine name. This model was released on 30th May 1967. The car had many " high tech " items for the late 60's, such a de-Dion rear suspension, front disc brakes and the semi-aircraft dashboard. (With Tachometer, Speedo, Oil Pressure gauge, Water Temperature gauge, Ammeter and Clock) Apart from these items and the styling, most of the car was conventional late 60's sports car. Most of the specifications are listed below. The L10A Cosmo was apparently ONLY sold in Japan. The engine is perhaps the main point of technical interest, called the L10A . With 2x491cc rotors and 110 hp it featured the same "stroke" as the later 10A, the 12A, 13B and 20B. ("stroke" meaning that a 13B rotor would fit into a L10A rotor housing, but the 13B rotor is much wider... Incidentally the only production Mazda rotary with different "stroke" was the 13A, used in the Luce R130). The rotor housings are hard chrome plated cast aluminum, apex seals are aluminum impregnated carbon-found to wear under 1.0mm in 100,000km driving. (Before this "new" apex seal design the rotor housings had severe "chatter" marks, so Mazda was overjoyed to solve that problem.) The side housings were also made of cast aluminum ( the only production Mazda rotary ever to use this) They were sprayed with carbon-steel for wear resistance. The rotor was made from cast-iron and featured twin side seals and triple oil seals (today's 13B has only a single side seal and twin oil seals). Ignition timing was: Leading - 2° ATDC / Trailing - 7° ATDC The eccentric shaft was made from chrome-molybdenum steel. Most of the other techniques used in the engine are standard practice today (eg oil spray to cool the rotors, oil cooler, gear type oil pump, oil metering pump to put a small amount of oil into the intake, axial flow water cooling ...) The engine weighed 102kg and was L508mm x W594mm x H544mm. It should be noted that by 1967 standards the L10A Cosmo's performance was excellent. It's quarter mile time of 16.3s is quicker than a 1984 GSL-SE RX-7 which did the quarter mile in 16.4s (with a 6 port fuel injected 13B making 135hp and 5 speed manual - admittedly the RX-7 is a pollution controlled vehicle, but it still indicates how good the Cosmo was) |
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The L10B was also the designation for both the car's model name and the name of the engine. This model was released on 13th July, 1967. The newer version of the Cosmo was slightly updated, with a 5 speed gearbox, power assisted brakes and optional air conditioning (which fitted behind the seats on the rear parcel shelf), and the wheel base was lengthened by some 150mm, which tended to make the car look more balanced. The car was also given a much larger radiator grille for cooling. Larger 15 inch steel wheels were used. Finally, the overall weight was up by 50kg to 990kg. The engine (code number 0813) had more power (130 bhp), thanks to revised port timing and carburetion, however the basic design was unchanged. (The air filer enclosure was modified to have two intake tubes, the earlier Cosmo only had one). The L10B Cosmo was mostly sold in Japan, however as NSU granted Mazda a "world-wide" licence in 1968, a limited export program was undertaken. Due to the low volume / high costs the car was only sold to countries that had (or allowed) right hand drive cars, including France, Holland, Denmark, Belgium, Germany and Canada. None were officially sold in Australia, however about 5 have been privately imported, and 1 was officially imported for evaluation. Interestingly the exported cars were fitted with the earlier Cosmo's 110hp engine, 4 speed gearbox, 14 inch steel wheels, presumably avoid maintenance troubles. The export model was known as the MAZDA 110S (the 110 coming from 110 horsepower and the S meaning Sport). With 130bhp (20 more than the earlier Cosmo), the L10B was even faster, It's quarter mile time of 15.8s is only 0.8s slower than FC3S (2nd generation RX-7) 13B Turbo, with over 180hp at 15.0s. |
