Flypast111 here again with information regarding PAW 40TBR engine RUN-IN;

a) After 5+ 2oz engine break-in/run-in events, the engine showed non-functional high rpm operation … back & forth resonance … short-slow-run-stop operation …
b) Acquired an electric starter, backed-out compression T-screw, and attempted starter-powered high rpm operation => heard “metallic pop” sound coming from cylinder … clearly a “stuck/frozen” contra-piston condition …
c) Wandering needle valve repaired as follows => used Sullivan Proflex yellow large fuel tubing (PN-S216) placed over split-brass needle asy. … helps keep “squeeze” on split-brass mount ... seems to work so far ...
d) Refueled with self-made diesel fuel (above) and fired engine … success … ahhh soo good!
e) Engine RUN-IN proceed with two (2) more 2oz runs until … yeeewooow! … during third (3rd) 2oz run (eighth 2oz run since new) the engine rear screw-in backplate “popped” out … engine run up-down-slow rpm to nearly instant stall–stop!
f) Inspection … rear backplate appears to be in good working order except for light metallic roughness in first one-quarter (1/4) turn of machine thread … engine motor case mating thread appears to be in good working order as well …

Question: what is the “required” repair to reassemble engine rear backplate? (no gasket present)

Proposal: clean backplate and engine case thoroughly … use silicone sealant applied to backplate near mating surface seal (near threads) to engine block case … screw rear backplate into engine case with finger tightness plus one-eighth (1/8) to one-quarter (1/4) extra turn … to snug part to engine block case … allow joint silicone sealant to cure overnight … next-day, ready for engine operation again …

So please review the above and advise if this is a “correct” repair or otherwise … Flypast111