I'm floored .
Looking at how that vac advance is mounted thru the case, with the vac canister remote from the body, with a rod the the case, I couldn't imagine how vacuum could be created inside the body, never mind how wet those things get inside, while off-roading, absolutely amazing .
For all i know, taking it apart for inspection knocked a piece of swarf out that i didn't see that was corkscrewing the oil up like someone else suggested.
I have no idea why it was doing it before, and why it doesn't appear to be now. Im bumfuzzled.