A snap ring, similar in appearance to a piston ring, is installed on the gear before it is pressed back into its rotor recess, thereby permanently locking the gear in place. The process of retaining rotor gears involves the removal of the rotor gear and the cutting of a matching groove in both the outside diameter of the gear and in the recess of the basic rotor where the gear sits. While it is possible to tap the gears back down with a plastic hammer, the problem will persist until the rotors are replaced with retained rotor gear components. 005', little movement is required to jam the rotor between the side housings, causing damage. Since the stock rotor side clearance is about. If your engine will run near or above 8,500 RPM for extended periods of time, the rotor gears will very likely 'move away' from the basic rotor. If you do not intend your engine to run above 8,500 RPM the stock rotor is satisfactory, requiring only a careful inspection of the seal and bearing clearances, as well as the maximum width of the rotor. We utilize a CNC machining process to produce our Super Light-Weight Rotor assemblies that are packaged as a completely balanced unit, including retained rotor gears, and front and rear counterweights. Material can be removed from any rotor to further lighten it while retaining the strength necessary for high RPM operation. Therefore, the 1984-85 12A rotor is the best choice. The power difference between the 12A rotors is negligible (at optimum ignition timing) except for one factor - the 1984-85 model was lighter. However, 1974-75 12A engines have a symmetrical combustion chamber (and will interchange front-to-rear) while 1976-85 rotors were asymmetrical in the combustion depression. Only one style of rotor is available for the 1974-85 13B engine. The rotors used in the turbo engines are lower compression, as compared to their non-turbo counterparts- 8.5:1 vs.

However, the 1986 and later rotors should never be used in 1985 and earlier engines due to geometry and compression ratio differences. Up until the introduction of the RX-8, the 1989-95 rotors were the lightest production rotors and can still be installed in the 1986-88 engines if you also include the matching front and rear counterweights. Over the years, Mazda has reduced the weight of the rotor assemblies in an effort to improve performance. Engine RotorsĪll Mazda rotors consist of two (2) main pieces: the basic cast iron rotor and the steel rotor gear that is held in the basic rotor by 9 or 12 roll pins. Racing Beat's carbon apex seals for high RPM and racing applications.

Satisfactory rotor