There should not be a significant amount of oil going into the gearbox through my drilling when the engine does not breath into the primary with a decent seal on the crank. With a reed breather somewhere on the engine there should be a net depression in the crank case so only air from heat expansion in the primary needs some venting. Anyway , I´d rather have "all that oil" going into the gearbox than all over the engine from the dynamo leak .
To be open, there will be another year or so of restauration work for me to find out what way the oil will go. A non-functioning crank seal may throw out oil via the dynamo - but same flaw on the crank may suck primary oil into the crank case when you have a net depression in there from an effective engine breather. So whatever happens at the dynamo "breathing spot" or my drilling into the gearbox filler depends on some other factors - more things to think about . . . . .
Vic
To be open, there will be another year or so of restauration work for me to find out what way the oil will go. A non-functioning crank seal may throw out oil via the dynamo - but same flaw on the crank may suck primary oil into the crank case when you have a net depression in there from an effective engine breather. So whatever happens at the dynamo "breathing spot" or my drilling into the gearbox filler depends on some other factors - more things to think about . . . . .
Vic