Personally, id suggest using a 0w/30 car engine oil, as afterall, this is designed for engines and use in engine cylinders. transmission oils and ordinary oils can be attacked by the residue left by combustion in the engine cylinder, causing more harm than good.
this stuff is thin enough to be recommended for turbo engines and their high temperatures way beyond what an r/c will reach and also contains enough addatives to reduce the corrosive effects of combustion residue inside the motor.
Ok, so you may have to buy a 1ltr bottle, but think how long it will last you as compared to the high price you pay for a minute little container of sewing machine oil.
