Hmm, I couldn't disagree more. A lapped system requires extremely precise machining and very careful control over the materials. A ringed system seems to be almost entirely dependent on the particular batch of iron you get, and the rest of the piston/liner, etc can be extremely crude by comparison. It seems to be a complete crap-shoot when it comes to batch-to-batch variations. Ringed systems were designed in the steam engine era when it was literally impossible to hold tight tolerances, and thus you added a spring element that conformed to whatever machining inconsistencies were present.
Hmm, I should think longer to be able to say what I have in mind but I'll try anyway:)
Yes, lapping and honing needs extreme precision, but that kind of precision is difficult to specify. It's a bit more artistic than usual machining. But in mass production, average results are acchieved more easily than in making of good ringed setups, with machine grinding and hand finishing.
I fully understand your thinking but still, the faults and failure modes that you describe are largely results of bad metallurgy, materials, tolerances etc, as I wrote earlier.
Why would you not put the same extreme precision and correct metallurgy into a ringed setup? Because that's what was missing in the time when you got your traumas.
Another thing is that the very basis of a modern lapped engine technology is largely a result of tinkering of the other guy behind our little engine, Rob Metkemeijer. So technically we could do whichever, lapped or ringed.
I think that by choosing the ringed, Rob eliminated lots of variations that may occur with lapped geometry, certainly it would take much longer to find the optimal geometry. And the integrated cylinder structure, close to ideal metallurgy and piston porting eliminates quite well the hot spots that are a main reason behing instability.
I have had similar discussions with Yuriy Yatsenko, he is also quite interested in ringed engines but he can't make them with the required repeatability and precision.
In ST etc. era, manufactury costs were certainly less than costs of producing lapped engines, but if you want to do it well, it becomes very time consuming and cost-ineffective.
L