[Marshall V. Daut]

Brass is softer than the cast iron engine block, so I suspect someone had screwed in a bolt first, ruining the pipe threads. A brass fitting was a post-stupid mistake attempt to correct the problem caused by the bolt. But the pipe threads in the block were already ruined. If you have access to pipe thread taps, try re-cutting the threads in the block. The incorrect bolt, followed by the brass fitting, may have changed the threads to the point that a good tap might give you enough usable threads to seat the plug. The deeper you can go with the plug, the better (unless it bottoms out against the oil pump, which is not a good thing). After re-threading the engine block hole, coat the plug with a good goop, as previously recommended, and screw it in as far as you can. But until you can get that plug to grab engine block threads, simply gluing the plug in place will not work. The pressure at the this spot in the oil pump is amazing. It will squirt oil halfway across your garage floor with the engine running! Simply gluing it in place and expecting that poor little plug to resist such pressure over the long haul is wishful thinking.
Marshall