Originally Posted by Chris W

In regards to ringed pistons not working well as diesels, I wonder if a purpose built modern ringed engine might actually work rather well.
For those who know a bloke called Lauri Malilla, he makes his own ringed control line stunt engines and has mentioned that most production ring setups are woeful.
Get the bore perfectly round, a correctly gapped well fitting ring and most might be pleasantly surprised as to how well they can seal.