An oil cooling structure of an engine is provided that is capable of enhancing cooling performance of oil while preventing an increase in number of components or an increase in required space from being involved as much as possible. In an oil cooling structure of an engine in which a transmission case is attached to one end wall of an engine body, and a transmission mechanism for an accessory drive is provided in the transmission case, the transmission case is formed into a potlid-shaped body having a plurality of rib walls along a front-rear direction, and is attached to an engine front wall with an engine cooling fan, and case inner chamber portions partitioned by the rib walls in the transmission case are configured as a transporting passage of oil circulated by an oil pump.

A seal structure for an internal combustion engine comprising: a cover side seal member which extends on upper surface sides or lower surface sides of both of an engine main body section and a chain casing and pressed and held against a cover member; a casing side seal member arranged at left or right end section of one end surfaces of the engine main body section onto which the chain casing is attached and pressed and held against the chain casing; a receiving concavity formed to extend on a junction surface of the chain casing to the cover member; and an extremely thick connection block section formed integrally on one end section of the casing side seal member, fitted into and retained by the receiving concavity, and projected more toward the cover member side than a junction surface of the chain casing to the cover member in a free state.

A case that houses a chain includes a first cover member fixed to a cylinder block and a cylinder head, and a second cover member arranged on the opposite side of the cylinder block and the cylinder head from the first cover member. In an intermediate part, which is a part of a confronting wall of the first cover member between the first flange and the second flange, a cover-side rib is provided, having a height so that a distal end of the cover-side rib is not in contact with the cylinder block.

A sealing structure for a front cover of an engine includes a front cover made of resin of an engine in which a through-hole, into which a boss part of a torsional damper is to be inserted, is provided, and a sealing apparatus to seal between the through-hole of the front cover and the shaft part. The sealing apparatus includes a support ring that is made of resin and has an annular shape, and an elastic body part that is made of an elastic material, has an annular shape and is attached to the support ring. The elastic body part has an annular seal lip that contacts the shaft part such that the shaft part is able to slide, and the support ring is bonded to the front cover.

The overhead camshaft engine (10) includes a cylinder block (11), a crankcase (12) attached to a lower part of the cylinder block to define a crankcase chamber (32), a bearing retaining member (60) attached to a part of the cylinder block, a crankshaft (20) rotatably supported by a pair of bearings (21, 22) supported by the cylinder block and the bearing retaining member, respectively, and a crankshaft pulley (53) attached to a part of the end of the crankshaft projecting outward from the bearing supported by the bearing retaining member.

A case for an endless transmission member includes a first case member attached to a vehicle-mounted internal combustion engine and a second case member attached to the first case member. The first and second case members define an accommodation chamber that accommodates an endless transmission member looped over rotating bodies of the engine. The first case member includes a communication hole that connects the accommodation chamber to the inside of the engine. The first or second case member includes a guide rib that guides lubricant from the accommodation chamber to the inside of the engine. In an orientation of the case when the engine is installed in a vehicle, the guide rib is provided along part of the lower side of the opening edge of the communication hole including the lower end of the opening edge.

A cover for an internal combustion engine is configured to be attached to an engine main body so as to cover a timing chain or a timing belt. The cover for the internal combustion engine includes insertion holes configured to receive a crankshaft or a camshaft. The cover for the internal combustion engine includes a first member made of a hard plastic and a second member made of a material different from the hard plastic. The first member is produced by insert molding with the second member embedded in the first member. A periphery of at least one of the insertion holes in the second member includes a joint surface that is joined to the first member. The joint surface includes annular grooves surrounding the insertion hole, the annular grooves being arranged in a radial direction of the insertion hole.

A marine engine comprises a powerhead having an engine block, a cylinder head and a crankcase containing a crankshaft. Operation of the marine engine causes rotation of the crankshaft. A crankcase cover encloses the crankshaft in the crankcase. A supercharger is on the crankcase cover, the supercharger being configured to provide charge air for combustion in the powerhead. A cooling passage conveys cooling fluid between the crankcase cover and the supercharger so that the cooling fluid cools both in the crankcase and in the supercharger.

A sealing structure for a front cover of an engine includes a front cover made of resin of an engine in which a through-hole, into which a boss part of a torsional damper is to be inserted, is provided, and a sealing apparatus to seal between the through-hole of the front cover and the shaft part. The sealing apparatus includes a support ring that is made of resin and has an annular shape, and an elastic body part that is made of an elastic material, has an annular shape and is attached to the support ring. The elastic body part has an annular seal lip that contacts the shaft part such that the shaft part is able to slide, and the support ring is bonded to the front cover.

A cylinder head cover structure for an engine includes a cylinder head cover. The cylinder head cover includes a metal cover member forming one end of the cylinder head cover in an engine length direction and a portion adjacent to the one end, and a resin cover member forming a portion of the cylinder head cover other than the metal cover member. The metal cover member is provided with a cam angle sensor attachment to which a cam angle sensor is attached, the cam angle sensor detecting a rotational position of a camshaft of the engine.