MAZDA LUCE RX-4
The introduction of the Savanna lifted Mazda’s annual rotary production past the 100,000-unit mark, but Toyo Kogyo remained committed to offering the rotary in nearly all of its products. Next in line was the second-generation Mazda Luce, which arrived in October 1972. (Except for the rare front-drive R130, the previous-generation Luce had been offered only with piston engines.) Unlike its Bertone-styled predecessor, the second-generation Luce was designed in-house; the new car had sporty proportions, but drew criticism for its fussy detailing.
The Luce was initially offered as a four-door sedan in Special, GR, and GRII trim, or a two-door hardtop coupe in SX, GS, GSII, or luxurious Grande trim. (A four-door wagon — offered in the same trim levels as the sedan plus a Grand Turismo version with fake wood paneling — was added in 1973.) Non-rotary cars were once again powered by a 1,796 cc (110 cu. in.) SOHC four, but the rotary cars had the 12A engine with either 120 or 130 PS (118 or 128 hp, 88/96 kW) and offered a choice of four- or five-speed manual gearboxes or JATCO automatic. There was also a thermal reactor-equipped AP version, which became a popular fleet vehicle in Japan.
A facelifted Series 2 Luce arrived in December 1973, including a new front clip for sedans that made them look more like the coupes. Both coupe and sedan were now available in GT form, with wider tires, radius rods for the rear axle, and a new 1,308 cc (80 cu. in.) 13B engine with 135 PS (133 hp, 99 kW) and 133 lb-ft (180 N-m) of torque. The extra power made the Luce GT the fastest rotary Mazda since the Cosmo Sport L10B; Toyo Kogyo quoted a top speed of 121 mph (195 km/h) and a 0-400 meter (quarter mile) acceleration time of 15.8 seconds.
The first Luce exports began in early 1973, badged 929 in piston-engined form, RX-4 with rotary power. American buyers didn’t get the piston-engined Luce (the 929 wouldn’t be offered in the States until 1988), but the U.S. RX-4 arrived in early 1974. The RX-4’s sole engine was the federalized 13B, rated at 110 net horsepower (82 kW) and 117 lb-ft (159 N-m) of torque, mated to either a four-speed gearbox or the three-speed automatic. The five-speed gearbox wouldn’t arrive until 1976, part of an effort to improve fuel economy.
TROUBLE IN PARADISE
By the fall of 1973, Toyo Kogyo was riding high. Total passenger car production for the calendar year would be more than 450,000 units, up 50% from 1970. To accommodate its export business, the company now had assembly plants in Malaysia, Indonesia, New Zealand, and South Africa, with a new Philippine plant following in January 1974. U.S. sales for the 1973 model year had totaled more than 117,000, nearly twice the previous year’s figure.
By 1973, interest in the rotary engine was also reaching its peak. The pending U.S. NOx standards meant that nearly every automaker in the world was at least considering offering rotary power. GM was paying $5 million every six months on a $50 million license from NSU and Curtiss-Wright while promising that the two-rotor GM Rotary Combustion Engine (GMRCE) would go on sale by the 1975 model year. Nissan and Toyota had taken out licenses of their own in 1971 and 1972, while Ford hoped to get a leg up by acquiring a piece of Mazda. (Negotiations collapsed when Toyo Kogyo made it clear the rotary would not be part of the deal.) Mazda’s American advertising cheerfully pointed out that what other automakers were still struggling to develop, Mazda already had; the company built its 600,000th production rotary in 1973.
Despite that success, all was not rosy for Toyo Kogyo and the company was already facing a number of serious problems.
The first issue was currency exchange rates. Since 1949, the value of the Japanese yen had been fixed at ¥360 to one U.S. dollar. The Nixon Administration’s decision in August 1971 to abandon the gold standard, which had kept the value of the dollar relatively stable, led to the collapse of the Bretton Woods system of fixed exchange rates based on the dollar. Allowed to “float” on the currency trading market, the yen’s value quickly increased, climbing to around ¥270/dollar by 1973. That shift, combined with new U.S. tariffs on imported goods, led to an escalation in the U.S. prices of various Japanese-made products as manufacturers struggled to keep pace. That inflation affected all Japanese automakers doing business in the U.S., but was particularly troublesome for Mazda, whose rotary products had been fairly expensive to begin with.
The second problem concerned the rotary’s reliability and maintenance costs. Despite their mechanical simplicity, the Mazda rotaries were not necessarily any cheaper to maintain than a four-cylinder reciprocating engine; oil consumption was inherently high and early engines had two ignition systems to maintain as well as a prodigious appetite for spark plugs. Both J.D. Power & Associates and Consumer Union (publisher of Consumer Reports) reported problems with seal failures in federalized 10A and 12A engines. In sharp contrast to NSU’s experience, Mazda’s apex and corner seals turned out to be surprisingly robust in service — several automotive magazines did teardowns of high-mileage Mazda rotaries and found little wear in those areas — but the same was not necessarily true of the oil seals or the gaskets mating the rotor housings to the side plates. On early engines, those seals were rubber O-rings, which took a beating from the rotary’s considerable waste heat, limiting their lifespan.
By the 1973 model year, Toyo Kogyo had developed more durable seals, but some owners complained that the company was reluctant to replace the seals on earlier cars under warranty. Mazda’s U.S. organization responded in March 1974 by adding a three-year, 50,000-mile (62,500-km) warranty for new rotary models, but complaints about earlier cars eventually resulted in a lawsuit that was not settled until 1980.
The third problem was the rotary engine’s high fuel consumption. As we mentioned in Part 1 of this story, the rotary’s combustion chamber has a large surface area for its volume, resulting in reduced thermal efficiency; more of the heat of combustion is lost to the cooling system than in a typical overhead-valve piston engine. Furthermore, the large surface area can create an effect called wall quench, where some of the vaporized fuel mixture re-condenses on cooler areas of the combustion chamber (or even on the rotor itself) and passes into the exhaust stream without burning.
Fuel consumption was even heavier on emission-controlled cars thanks to their thermal reactors. The thermal reactor was essentially an afterburner, injecting fresh air into the exhaust stream to continue the combustion process. Although the afterburner’s purpose was to reduce hydrocarbon emissions at the tailpipe, the thermal reactor didn’t work effectively unless the exhaust leaving the engine had high levels of unburned hydrocarbons. To accomplish that, Toyo Kogyo opted for very rich fuel mixtures, making Mazda’s early emissions-controlled cars even thirstier.
By U.S. standards, the rotary’s fuel consumption only seemed unreasonable in comparison to four-cylinder rivals; it was roughly comparable in fuel economy to a big American six. However, when the U.S. Environmental Protection Agency (EPA) ran a 1973 Mazda RX-2 through the new EPA simulated fuel economy cycle, the RX-2 returned a dismal 10.6 mpg (22.2 L/100 km); the smaller RX-3 did little better. The EPA eventually adopted new test procedures intended to more accurately reflect real-world driving conditions (including the now-familiar city/highway split), but that did Mazda little good in the short term; the early test results put the Mazda rotaries in the same league as full-size American luxury cars with big V8s.
Kenichi Yamamoto, the head of rotary development, was already working on improving the rotary’s fuel economy, but political events elsewhere in the world were moving much faster, creating a crisis that would nearly become Mazda’s undoing.