PCV for MF 135

The draft tube on most tractor engines takes these same gases and vents them overboard to the atmosphere. The products of combustion are ideally CO2 & water vapor but some other compounds are also produced,some of which are combustible and some of which aren"t. Oil particles are among the constiuents of typical blow by gases. Very little if any raw gas is contained in blowby gas unless the carb is misadjusted and/or the engine is badly worn. I don"t see why there would be any appreciable effect on the oil change interval since it doesn"t make much difference whether you pass the blowby gas from the crankcase to the manifold or from the crankcase to the atmosphere. I don"t know what you mean by the "air box" but if that is up stream of the carb then you"ll risk fouling up the inside of the carb with blowby gas. If I were going to do this I"d tap the intake manifold downstream of the carb but I don"t understand what you hope to gain by doing this.