Castrol M is there racing castor oil which is very suitable for these high reving glow engines but i must say i don,t like to use castor oil as a total lube compared to years ago when this was the only oil before any synthetic oils came on the market, running straight castor does eventually clog bearings and glaze piston liners so it is prefered to use castor as a percentage with a synthetic oil, i use 18 percent synthetic and 2 percent castor. even model engine manufacturers state to use a simular oil mix. not castor only.