The Stovebolt Site Forums The Shop Area Engine Shop what about a bore endoscope to inspect cylinder for debris?

Here's the one I bought (actually, two - one for me and one for son-in-law).
Wireless endoscope
It works under gasoline (used mine to inspect the fuel pickup in my boat when I had a problem with it). You can use your iphone to take a video which works better than still pics as the wire th camera is on is hard to hold still if extended very far. The camera is pretty small and would easily fit into a spark plug hole.
Would work pretty well to look into a cylinder, IMO.