Abstract: An engine is equipped with a variable valve timing mechanism, which is operated by a working oil to change rotating phase of a camshaft to thereby change the valve timing, and includes an oil passage formed in a chain case and an oil passage formed in the cylinder head so as to be communicated with the hydraulic actuator, in which the oil passages communicate with each other at a contact surface between the chain case and the cylinder head, and the working oil is supplied from the hydraulic control valve to the hydraulic actuator. The variable valve timing mechanism further includes a block disposed independent of the chain case between an inner wall of the chain case and an end wall of the cylinder head, and an intermediate oil passage formed in the block and including communication openings in which one of the communication openings is offset in position from another one thereof.

Abstract: An engine is equipped with a variable valve timing mechanism, which is operated by a working oil to change rotating phase of a camshaft to thereby change the valve timing, and includes an oil passage formed in a chain case and an oil passage formed in the cylinder head so as to be communicated with the hydraulic actuator, in which the oil passages communicate with each other at a contact surface between the chain case and the cylinder head, and the working oil is supplied from the hydraulic control valve to the hydraulic actuator. The variable valve timing mechanism further includes a block disposed independent of the chain case between an inner wall of the chain case and an end wall of the cylinder head, and an intermediate oil passage formed in the block and including communication openings in which one of the communication openings is offset in position from another one thereof.

Abstract: A chain case structure of an engine includes an oil pump is disposed in a chain case and driven by a crankshaft of the engine and an oil pump case. The oil pump case includes an oil strainer mounting portion, an oil suction passage communicating the oil strainer mounting portion with a pump chamber, and a chain guide portion protruding toward the one end in the crankshaft direction of the engine and extending along an outer periphery of a timing chain. The oil strainer mounting portion is disposed below the chain guide portion, the oil suction passage portion is expanded from a wall surface of the oil pump case toward the engine and extended toward the chain guide portion, and the oil strainer mounting portion and the chain guide portion are connected by the oil suction passage portion.