Oh, yes im late here...this engine is an Plain Bearing Raduga 7M, yes...

Paulino please put this engine in the trash somewhere, the piston of this thing isn't aluminum, it is cast iron and it is much to heavy.
This engine when running will shutter your RC in to parts. In a east german magazine was 30 years before was an article where the author
tried to solve this problem by making cut outs from the piston and removed as much as possible from the crank pin end of the crankshaft,
it will be run better but still is vibrating like hell. I got such a thing a half year ago with a bunch of other dumped engines, I don't even
looked at it closer since I already had such a thing around 1980...

Regards,
Holm