4-CYCLE INTERNAL-COMBUSTION ENGINE

摘要

PURPOSE:To make a smooth returning of lubricant from a cam chamber to an oil pan by a method wherein each of the lubricant returning port at the crank chamber and the lubricant returning port at the cam chamber is independently opened into the oil pan. CONSTITUTION:The lubricant dispersed into a crank chamber 28 is returned into an oil pan 51 through an oil return passage 62. The lubricant after its lubrication for a cam shaft 36 is returned into the oil pan 51. A return port 66 of the oil return pasage 62 and a return port 67 of an oil return passage 65 are placed adjacent to an opening 68 formed at a relatively narrow part which is positioned substantially at a central part of the oil pan 51, respectively, and separated to each other by a partition wall 69 projected at the under surface of a cylinder case 20.