Let me present to you my last engine. It is the second version of a 32cc I made last winter. The modifications I made this time have reduced the displacement at 26cc. It works better but I have still problems with the seals. Currently they are still quadring seals like on the first version and my previous engines. This last version has convinced me that this kind of seals are not suitable for this use. For the third version, I will try PTFE seals that I will machine myself.
My goal is to make CHP. Not with this one, it's only an experience to try to find an architecture which will be efficient and easy to make in the same time. I know that a lot of persons tries to achieve for the same goal. I hope it will interest you.