Wankel rotors of 13B The 13B is the most generally manufactured rotary engine. It absolutely was The premise for all long run Mazda Wankel engines, and was produced for more than 30 a long time. The 13B has no relation towards the 13A. As an alternative, It's really a lengthened Variation in the 12A, possessing 80 mm (three.The parents at JJSmotor