ORIGINAL: Ram Jet
Yes, I agree. Fuel/oil/nitro combo requirements for each engine are as varied as prop diameter and pitch. Most of us just don't bother to experiment. I'll be interested in Frank Bowman's view on this end gap issue. Honda recommends an end gap of .0118 on my 500cc 4 cycle single. If the .004"/1" piston diameter guideline were applied .014" would be acceptable. At .0197 honda specifies replacement. It looks like Honda leans toward .0035/inch. Interesting.
Bill
4 stroke model engine and 4 stroke engine with oil in the pan are the ring gap not the same. We should not have larger ring gap in the 4 stroke engine with its own oil lubrication system in that oil consumption will not increase and in addition there is an oil scrape ring that keeps the oil away from the combustion space.
For small ring gap leads to the ring expands and running tight in the cylinder. For a large ring gap leads to compression loss. Right gap size in the upper and lower limits in the ring gap for 4 stroke engine model is not easy to measure. The engine are running without problems and it comes enough oil out of the crankcase means the ring gap are in the "right sized gap"