Very nice videos and pictures. No, the looseness in a valve guide wouldn't cause 0 PSI compression. The tightness you described with the exhaust valve is not unusual, but might indicate carbon build-up on the stem- from valve guide wear or the stem O ring seal leaking.
As a bit of insight, make sure all the valve springs are installed right side up- the ones in your picture are correct, with the close coils at the bottom. A spring being upside down won't cause 0 compression, but it likely will lead to valve breakage, a hole in a piston, a lot of noise and shaking before you stop the engine, then 0 compression in that cylinder. But from all evidence, you aren't there yet- fortunately.
I agree with atomarc- there is still something missing here. Back to a malfunction with your compression gauge? While that likelyhood seems to have been eliminated by your previous checks, your disassembly and accompanying pictures haven't shown any explanation for the loss of compression. What did the engine sound like when you did the original compression check? With all the spark plugs out, and the gauge attached to a cylinder with zero PSI, you would only hear the normal starter "whirring" of no compression, not the usual "grunt" (for lack of a better word) of compression. Do you remember what you heard for that test?
Harvester
