[DavidG]

ursus,

With respect, it was not a quirk, but rather intentional as the hole was covered for a reason, namely to avoid excess oil from getting on the shaft and possibly working its way upward with the rotation of the shaft and fouling the points. That upper bushing was not an ordinary solid brass bushing, but rather was porous to feed the shaft oil very slowly. The same special material was also used for the bushing on the front of the shaft in V8 distributors.


If you replace the upper bushing with one made of solid material you will most certainly starve the upper shaft of lubricant.