The distributor has a minor failing in that the oiler (brass knob above - most are steel) lubricates only the lower bushing of the distributor shaft.
Aftermarket available is a shaft and cam retainer screw that is drilled and has a small oil port aimed at the upper bushing.
But you can use your oilcan and "gush" oil through the lower brass/steel oil cap. A surplus of oil MAY get that upper bushing. Excess simply follows the distributor shaft back into the engine.
Joe K