Me too! In my die cast C motor 10545. Bush seized onto the spindle, well tight! Had to split it longitudinally with a hacksaw blade. Polished the spindle & fitted the the pinion from my '48 B motor which has what appears to be a cast iron? sleeve. The inside of that sleeve had plenty of natural lubrication grooves, it gave the distinct impression of having been drilled in manufacture, not bored, and certainly never honed!
So is there a preference for sleeve material?
I need to make a new bush to replace the alloy one, I am leaning towards cast iron, an old sash window weight could be good?
There is a note in Instruction sheet 6 "The Timing Gear" page 3 under breather valves. It says the one piece cast iron type ET141/1 was found to be unsatisfactory under racing conditions and if fitted, should be replaced with one or the other of the composite pattern ET141/1AS which has a bronze sleeve or ET141/3AS which has a cast iron or light alloy sleeve.
Not sure why the one with the cast iron sleeve is preferable to the one piece cast iron one.
Mine has a bronze bushing and the gear is stamped ET49/1, so a !/@ time pinion, but no keyways.