The large section at the top housed a set of spring loaded centrifugal weights and the shaft drives the oil pump at the bottom.
Obviously the first job was to strip it down in to its component parts. Then the usual cleaning up, etc, etc. Eventually it turns in to this:
Ensuring the oil pump had the correct thickness of cover plate joint took a while. To thin and the gears were tight against the cover plate. To thick and there would be to much clearance between the cover plate and the gears which would result in a noisy and inefficient pump. The task was done by trial and error with multiple 0.5mm joints (all hand cut) until the correct thickness was achieved.
New joints where made for all of the other mating faces and, after a bit of fiddling around the final result:
Another bit ready to fit come the time of the great re-assembly.