Dripless packing
Dripless packing is the only way to go. I have it installed on Moonrise and my bilge has very little or no water in it. This type of packing doesn't require leakage to cool the packing while the shaft turns. To answer your question though, the engine / shaft bilge is normally isolated from the main bilge to prevent oil leaking (or spilled) from the engine from inadvertantly being pumped overboard. If you decide to connect the two bilges I would suggest getting one of those tube oil catchers and just lay it in the bilge to catch the oil.