I did check with Horizon Hobby and it appears the repair costs would be at least as much or more that purchasing a new DLE 55RA. It seems a shame to me that one can't purchase parts and repair these engines ourselves. I think I could get by with a cylinder mounting ring with bolts and three valve push rods. I already have the push rods but the cylinder mounting ring is just not available. I am not sure I would have ventured into the radial engine world if I had realized one could not obtain repair parts. It looks as though I may also have a parts engine available. One thing that is so tempting is I have a new DLE 55RA sitting in its box under my bench. I was going to put that engine in a plane that I have not yet started but it may just end up in the Howard.
Best wishes and good safe flying.
Heli-NuBee (AKA Roger the radial rabbit)