Another "after" picture as in after I had mopped up the mess. We did some testing on the heli-parking ramp outside the shop and after running a ~40secs, in a simulated AX run, I hear a loud squeal from the belts and the engine sound changed.
Shut off engine, climb out and discover a substantial trail of fresh Mobil 1 running from the head down the block, and the crank pulley has a nice fresh layer of said oil. Eventually determined that the oil passage hex plug backed out of the head -
See here: http://www.pbase.com/aw11mr2/image/118659766; http://www.pbase.com/aw11mr2/image/118659963
- I attempted to insert a similarly sized bolt, and then went to a test day. In the first run, the bearing spun.