A Wankel-powered Sports Car from Japan
As long ago as 1920 Felix Wankel, a German engineer, was studying the problem of the rotary piston engine as opposed to the conventional reciprocating piston engine, and he worked constantly on the theory until in 1951 he gained the support of the N.S.U. company in Germany. By 1957 N.S.U. had a rotary piston engine working, known as the DKM type, in which the piston and the casing rotated, but as this introduced complications in manufacture they produced the KKM type early in 1958, in which the casing was stationary and only the piston rotated. By mid-1959 the KKM was undergoing endurance testing and at the end of the year it was announced to the world in general. By this time Curtiss-Wright in America had taken out a licence with N.S.U. and the Japanese Toyo Kogyo firm were showing interest. In July, 1961, an agreement was signed between N.S.U. and the Japanese for a licence to continue development work on the KKM engine for the sole purpose of bringing the engine into practical use as soon as possible. The Rotary Piston Engine Development Division of Toyo Kogyo was formed in 1963 and work progressed to multi-rotor engines, with two, three and four chambers, and during that year a prototype sports car was built to take various versions of the Mazda-developed Wankel engine. By early 1965 endurance tests of 100,000 kilometres had been completed on the Mazda 110S, known also as the Cosmo Sport. After a very full test programme throughout Japan in all weathers and on their own proving grounds, the Mazda 110S was put into production and distributed to Japanese dealers during 1966, and they put the model through large mileage endurance and usage tests, so that by May, 1967, the car was ready for sale to the public, and May 30th marked the beginning of a new era in motor history, when the first production car powered by a rotary piston engine was put on sale.
Toyo Kogyo Ltd. are now probing world markets and the Mazda 110S appeared at Earls Court last October and the British concessionaires in Newbury, Berkshire, have been lending a demonstrator model to the Press with complete confidence. The two-seater fixed-head coupé model has a front not unlike a Marcos 1800, with an air intake under the full-width bumper, while the centre-section and tail are reminiscent of a baby Ford Thunderbird. The body/chassis structure is conventional steel and front suspension is by double-wishbones and coil-spring/shock-absorber units. At the rear the differential unit is chassis-mounted with universally-jointed half-shafts taking the drive to each rear wheel and these are sprung on long semi-elliptic leaf springs, while a de Dion tube ties the wheel hubs together. The twin-rotor engine has 500 c.c. combustion chambers and is the equivalent of a 2-litre conventional engine. It is coupled to an orthodox all-synchromesh four-speed and reverse gearbox, driving through a normal type of clutch, the power unit being mounted in the front of the chassis but quite a long way behind the centre line of the front wheels. Disc brakes are used on the front and drum brakes on the rear and the pressed-steel 14-inch wheels have fancy perforated covers. The front track is 4 ft. 1¼ in., rear track 4 ft. 1 in. and the wheelbase 7 ft. 2½ in., while the overall length is 13 ft. 7 in. With full equipment including built-in radio and electrically operated aerial the car scaled 2,086 lb. (18 cwt. 2 qts. 14 lb.). The engine runs happily on cheapest petrol.
The Mazda 110S is known as the Type L10A, with 10A rotary engine, and it has comprehensive instrumentation, neatly grouped before the driver, the dials with white figures on black faces, comprising ammeter, fuel gauge, oil and water thermometers, clock and 200 k.p.h. speedometer with total and trip recorders by Toyo, and a Nenso tachometer reading to “9” for 9,000 r.p.m., red-lined from “7.” Flick switches, recessed within the padded cowling surrounding the black instrument panel, operate the various services, including the two-note horns and electrically operated radio aerial, which is fitted at the offside rear of the body. These switches are clearly labelled in large white lettering, the symbols being in English, or rather American, and easy to understand if given a little thought—CL for cigarette-lighter and ANT for aerial or antenna, for example, although ROOM, at one end of the three-tier heater-control quadrants is an unusual one.
A well-balanced right-hand stalk on the steering column controls lamps-dipping after a conventional pull-out knob has put on the side/headlamps; the knob of this stalk is turned to bring in the wipers, which sweeps the screen in opposition, while pressing the end of the stalk operates powerful TNK washers; the horn button is in the centre of the wood-rimmed wheel. To alter wiper speeds there is a flick switch on the instrument panel and at the moment there is no headlamps “flasher,” but this will be rectified. The Clarion radio is built into the instrument panel, has “searcher” type tuning and two speakers, like small boxes with chromium trims, mounted on the rear window ledge where they reflect badly in the rear window and the mirror, so that you continually think something is following you! There is an inspection plate for the fuel contents gauge on this rear shelf.
The recessed Koilo headlamps have air ducting to obviate condensation but this allows road muck to splash in, which is not good, and there are four large rear lights, which all light up on braking. These operate even with the ignition switched off, which is a good parking or stopping point; two reversing lamps are fitted. The headlights give a good spread but lack penetration and are not really adequate for fast night driving, while the full-beam indicator light between the main instruments is positioned to blind the driver! It was so bad that it had to be covered over by masking tape to make it tolerable, but the rheostat controlled instrument lighting was good. The lockable fuel-filler is beneath a small flap in the centre of the tail, between the rear window and the hoot lid and is easily reached from either side of the car. The tank holds 12½ gallons and is mounted ahead of the rear axle and leaves about two gallons when the uncalibrated gauge reads “E.” There is useful stowage space with retaining straps, on a ledge behind the bucket seats and a drop-lid lockable facia glove box, the lid dropping frequently over bad bumps taken at speed, the noise of which was a bit starting to inattentive passengers. The boot is shallow but reasonably accommodating, its lid having to be unlocked for access, and the spare wheel is buried in the floor of the boot. The 12 volt 25 a.h. negative-earth G.S. battery with visible fluid level is firmly fixed on the left of the boot, the lazy-tong screw jack is clamped on the right and the jack handle is held in rubber clips under the boot-floor carpet. A neat little zip-fastener hold-all contains the tool-kit, which includes an inspection lamp that plugs into a socket on the right of the engine compartment.
Reverting to the interior, which is black with check seat material, there are large rotary controls on each side that open and shut air-extractor vents, and there are three neat warning lights, clearly labelled BRAKE, BEAM, OIL.P in front of the driver, the BEAM being dazzling at night as already mentioned. A good item is that the white needles of the ammeter, and oil and water temperature gauges all hang centrally downwards when all is well, so that a quick glance is sufficient. When the ignition is switched off the temperature gauges read minimum, instead of the usual minimum, so a defective gauge would soon attract attention. The central hand-brake is on the left of the prop-shaft tunnel on r.h.d. cars and does not inconvenience driver or passenger. A big plated knob under the instrument panel locks the extendable steering column, a good point being that the indicator/wiper stalk and mounting move in and out with the wheel. The interior door handles are beneath the armrests and the window-winder handles have rubber knobs. The external door locks are in the push-buttons and work in conjunction with long-travel inside sill-buttons. One key works door locks, fuel filler and ignition, but another is needed for the glove-box and boot lid. Excellent leg-room complements the firm but practical seats and Takata Kojyo seat belts are fitted, but a grab handle would be appreciated by the passenger in view of high cornering powers the car can develop on its Goodyear G800 tyres. Apart from an excellent map light on a gimbal mounting like an aircraft air-vent there is no interior illumination, which is a short-coming. The interior trim is black and done without ostentation, there are solid-looking wrap-round bumpers, orange side-repeaters for the flashing indicators and faired racing type external mirrors to supplement the adequate interior one.
Under the front-hinged bonnet the barrel-shaped casing of the twin-rotor Wankel engine is impressive beneath the big yellow Roki air-filter, on which servicing data is listed, in Japanese and English. There are two NGK8 sparking plugs mounted one above the other to each rotor chamber with Nonshin coils and two distributors, one to the upper pair of plugs and one to the lower pair of plugs. The ducted radiator has a plastic fan driven by a single belt which also drives the Mitsubishi alternator. Mazda summer and winter coolants are recommended for the radiator, and stamped on the bulk-head is “Made in Japan.” The minimum servicing intervals are every 2,000 miles, with engine oil changes every 4,000 miles and chassis greasing every 20,000 miles.
The price of the Mazda 110S is not yet finalised but should be around £2,700 and it is handled by Mazda Car Sales (G.B.) Ltd., Pearl House, Bartholomew Street, Newbury, Berkshire, while Cumberland Garage, Bryanston Street, London, W.1., look after service and maintenance. For further reading about this interesting car during a 1,825-mile road-test, read the article “Pistons Going All Ways” on page 278 of this issue.
—D. S. J./W. B.