This research aims to develop parts for Advanced Fuel/Oil Filtering Re- circulation applicable to this kind of regulation proof engines. These parts can play a role of converting traditional air emission type crankcase into recovery type crankcase so that the engine can deal with environmental regulations, which do not allow minimal amount of toxic gas discharge. For the experiment, test method and specially made testing equipment are prepared. The results showed that Oil separation efficiency of the Cyclone type crank case oil separator was higher than one of the partition wall type in bench test and that Emission gas of the cyclone type oil separator was higher than one of the partition wall type in vehicle test.