Mazda still produces parts for its 13B rotary engine

Mazda has long been associated with rotary engines, but even though the Japanese carmaker has no immediate plans to develop a new sports car powered by such an engine, it still intends on keeping that legacy alive.

In an article posted on the Classic Mazda page, the company revealed that it continues to produce key components of its famed 13B rotary engine at its Hiroshima engine plant. Tetsuya Sato, a machinist with 36 years of experience in the factory, said that the machining tools used are unchanged from the past, although they require constant maintenance to ensure the parts are made to the highest degree of accuracy.

“Many people don’t know, but Mazda continues to manufacture rotary engines. They will be installed in new cars until the RX-8, but even after that. We continue to manufacture 13B repair parts and the engine body assembled with new parts. That is why this factory remains in this way,” said Sato.

Sato is part of a team of ten people that works in the factory, which has the ability to produce an average of 200 to 400 rotary engine parts that are shipped worldwide. The processes involved certainly require plenty of skill and experience to execute, as Yoshikazu Washio, another machinist with 35 years of experience, explains while making a groove on a rotor to set a part called an apex seal.

“The design of the groove width is 2 mm. On the other hand, it must be finished with an accuracy of -5 microns and plus 12 microns (1 micron = 1/1000 mm) by carefully and slowly scraping the rotor with a rotating whetstone,” said Washio.

“This task starts with carefully checking the thickness and condition of the grindstone before starting the process because the grindstone gradually becomes thinner over time. Also, should the surface of the grindstone be scratched, the inner wall of the groove will also be scratched,” Washio continued.

“Of course, if there is even a slight malfunction in the machine, it will ruin the rotor that has gone through many steps so far. So, it’s very important to keep making sure that you are in the best working environment every time,” he ended.

Meanwhile, factory foreman Hiromichi Abe said the 13B rotary engine actually has as many as 10 variations depending on the model and specifications of the vehicle it is installed in. “The finish of the parts used in each is different and they can be ordered from all over the world. Depending on the part, it may take one to two months to complete a part, and multiple parts might be combined into a single unit,” Abe explained.

A PDF posted at the bottom of the article shows a catalogue of rotary engine parts for the third-generation FD RX-7, with the most expensive item being a complete short engine that is priced at 860,981 yen (RM32,362). The FD and second-generation FC are currently part of Mazda’s heritage parts programme, along with the first-generation NA MX-5.