Lubricating and breather system in engine

摘要

A lubricating and breather system is provided for use with a crankcase and a cylinder block in both a horizontal-type engine and a vertical-type engine, in which the discharge of a blow-by gas and the circulation of oil separated from the blow-by gas into the crankcase can be reliably performed. When the engine is of a vertical-type, it includes a crankcase which is disposed so that a second bearing boss is located above a first bearing boss. The second bearing boss is provided with an annular chamber into which splashed oil produced in the crankcase is passed. A breather chamber is provided in a cylinder block to communicate with the annular chamber, and includes a first return bore provided in a portion thereof which is a lowermost portion when in the horizontal-type engine, and a second return bore in a portion thereof which is a lowermost portion when in the vertical-type engine.