Now I see where your inspiration has come from being around the small engine manufacturing industry.....your skills at recreating stuff from memory is quite awesome...
Wow I have never clicked the little bell until this video, so thats a lawnmower deck? I thought of stacking a few engine on top of each other but never a radial.
I read the comment about audio quality. I can hear you just fine and my desktop speakers are from the mid 90's! Love what your doing and looking forward to part 7. I would suggest using an assembly lube in place of oil for assembly, it's tackier and stays in place better than oil for initial startup. Once the engine is running, it mixes right in with the oil.
What a beautiful job you have done here. So far I don't quite understand how the ignition system works as there is one magnet on the flywheel but I am sure I will discover later. Could be that the magnet is not used. Pulling off a handmade Radial engine is I am sure very difficult as I have seen other youtubers try and fail.