[Jamesp]

I've been thinking about this problem and it seems clear that space is too limited to reach in and grab the lost fastener. You may be able to "walk" the fastener out of the block using neomydium magnets from the outside of the case. The magnetic field should easily penetrate the aluminum. I looked at the case geometry at it appears there may be clearance to move the fastener out of the well it is in using magnets from the outside of the case then to the point you say you can see with your endoscope then over to the opening in the block over the oil pan then into your hand. This will require rare earth magnets but seems like the best shot to me. The magnets never enter the case where they would stick to every ferrous thing in there you don't want them to. If you need pics I can post them after I'm home from work. And now, back to lunch!