Wankel rotors of 13B The 13B could be the most widely produced rotary engine. It had been the basis for all long run Mazda Wankel engines, and was made for more than 30 several years. The 13B has no relation to your 13A. As an alternative, it is a lengthened Variation of the 12A, obtaining eighty mm (3.*Free of charge goodies may or may not still