An engine includes a crankcase defining a crankcase space, a first shaft disposed at least partially within the crankcase and supported for rotation by the crankcase, and an oil pump coupled to the first shaft and operable to draw low pressure oil from the crankcase and discharge a flow of high pressure oil. A pressure relief path is positioned to selectively receive a portion of the flow of high pressure oil and a pressure relief assembly is coupled to the pressure relief path and is arranged to spray the portion of the high pressure flow that passes through the pressure relief passage against an interior surface of the crankcase.

An internal combustion engine for a motorcycle includes a rear cylinder head, the rear cylinder head being provided with a camshaft, an exhaust rocker arm rocked by the camshaft, an engine valve closed/opened by being push-pressed by the exhaust rocker arm, and a rocker arm shaft swingably supporting the exhaust rocker arm. In the internal combustion engine for the motorcycle, the rear cylinder head is provided separately from a holder member, the holder member being provided adjacently to the rear cylinder head, the camshaft is rotatably supported by the holder member, and the holder member is provided with right and left rear side walls and internal combustion engine supporting portions, the right and left rear side walls supporting the rocker arm shaft, the internal combustion engine supporting portion being supported by a vehicle body frame.

Described is a crankcase and a method for assembling a multi-part crankcase. The method can include providing a cylinder block and a bearing tunnel upper part. The cylinder block has a plurality of threaded holes into each of which a stud screw is screwed, where the stud screws protrude from the cylinder block. The bearing tunnel upper part has a plurality of through-holes, where each of the through-holes is arranged coaxially to a corresponding stud screw. On a side facing the cylinder head, each of the through-holes has an internal thread having a first direction of rotation. A plurality of threaded sleeves, each threaded sleeve has an internal thread that has a second direction of rotation, an external thread that has a first direction of rotation, and a driver profile for inserting a screwdriver tool in a positive-locking manner, are provided.

An engine block, an engine sub-assembly, and method for providing and manufacturing an engine block. The engine block includes a plurality of cylinder barrels positioned in the engine block, at least one oil jacket channel formed in the engine block, and an oil inlet port positioned in a peripheral wall of the engine block and connected to the at least one oil jacket channel. The at least one oil jacket channel includes a plurality of curved channel sections. Each curved channel section in the plurality of curved channel sections extends about at least a portion of a circumferential portion of a respective cylinder barrel in the plurality of cylinder barrels. The at least one oil jacket channel extends between adjacent cylinder barrels of the plurality of cylinder barrels in the engine block.

An engine includes: a cylinder block that has a cylinder included in a combustion chamber; a crankshaft that is placed in the cylinder block; a flywheel that is mounted to one end portion of the crankshaft; and a flywheel housing that is placed on a side of one end face of the cylinder block in a direction of the crankshaft and that houses the flywheel. The flywheel housing has a blow-by gas path through which a blow-by gas passes.

A system for making a hybrid cam bore sand core with metal chills for an engine block includes an engine block cast of an aluminum material. A camshaft bore extends through the engine block. A cam bore sand core with at least one metal chill is positioned within the camshaft bore. A body portion of the at least one metal chill is positioned in direct contact with a cam bearing surface of at least one cam bearing member during casting of the engine block to increase a cooling rate of the at least one cam bearing member and create a crystalline material depth of the cam bearing member having enhanced mechanical properties.

A system for making a hybrid cam bore sand core with metal chills for an engine block includes an engine block cast of an aluminum material. A camshaft bore extends through the engine block. A cam bore sand core with at least one metal chill is positioned within the camshaft bore. A body portion of the at least one metal chill is positioned in direct contact with a cam bearing surface of at least one cam bearing member during casting of the engine block to increase a cooling rate of the at least one cam bearing member and create a crystalline material depth of the cam bearing member having enhanced mechanical properties.

An internal combustion engine includes a crankcase that rotatably supports a crankshaft, a case cover that liquid-tightly covers a side of the crankcase, a cylinder block that is joined to the crankcase and divides a plurality of cylinders in a V-type arrangement in which the cylinders are disposed above a virtual horizontal plane including a rotational axis of the crankshaft and intersect each other at a bank angle, a to-be-detected body that rotates integrally with the crankshaft, and a detection sensor that is mounted from the outside on the crankcase at a position higher than the virtual horizontal plane and is made to face a trajectory of the to-be-detected body to generate a pulse signal in response to movement of the to-be-detected body. This provides, in a so-called V-type internal combustion engine, a structure for disposing a detection sensor that can detect the angular velocity of a crankshaft with high precision.

A structural frame is provided. The structural frame includes a bottom surface, first and second cylinder block sidewall engaging surfaces, the first and second cylinder block sidewall engaging surfaces positioned above the bottom surface at a height that is above a centerline of a crankshaft support included in a cylinder block when the structural frame is coupled to the cylinder block.

A marine engine has a cylinder block comprising first and second banks of cylinders disposed along a longitudinal axis and extending transversely with respect to each other in a V-shape so as to define a valley there between; and a lubricant cooler located in the valley and extending parallel to the longitudinal axis. The lubricant cooler has a lubricant conduit that conveys engine lubricant parallel to the longitudinal axis and then transversely to the longitudinal axis to the cylinder block. The lubricant cooler further has a cooling conduit that conveys cooling fluid alongside the lubricant conduit to thereby cool the lubricant conduit and the engine lubricant therein.