Rolls-Royce 20/25 - starter motor clutch bits



motor shaft


The complete motor without its clutch assembly.  The splined on the shaft end have two short, double-width, splines to accommodate the dog plus one longer double-width spline for the nut that holds the friction disks.

pinion & cage


The forward-facing end of the clutch cage and the pinion that connects with the starter ring on the flywheel.

pinion back


Both of the previous components inverted.  The central bush on the pinion acts as a limiter for the hollow shaft.  The washer, shown uppermost here, is free to rotate and supports the large spring.



From the left: the shaft and return spring; threaded nut that carries the friction disks; end plate; dog nut.

The dog nut is left hand thread and locks the end plate against the machined ring on the right of the carrier nut.

cap and ring


The end cap for the clutch assembly and the lock ring that holds everything in place.

spring body


Two of the cage legs have been damaged.  The locking slot has completely snapped off one leg and is half-missing on another.  The cage has been in this condition for at least 20 years nd has caused no problem.  Internal spring pressure is relatively light and the circular lock ring will still keep everything in place.

The block at the bottom of the picture is inverted.  The brass pressure plate is spring loaded to avoid damage to the pinion.  The main internal spring locates against the flange.