Systems and techniques for identifying abnormal exhaust valve performance of an internal combustion engine may include receiving exhaust passage temperature signals from a plurality of exhaust passage temperature sensors, each exhaust passage being fluidly connected to one or more exhaust valves of the internal combustion engine, the exhaust passage temperature signals being indicative of respective exhaust passage temperatures. The method may further include comparing one or more of the exhaust passage temperatures, identifying a caution exhaust passage temperature, from one or more of the exhaust passage temperatures, that deviates from one or more of the other one or more exhaust passage temperatures, and outputting an abnormal exhaust valve performance indication based on identifying the caution exhaust passage temperature.

A technique for testing a pushrod valvetrain in an engine includes replacing an original pushrod with an instrumented pushrod (IPD) which includes a sensor configured to measure strain and/or motion. The engine is then operated, and the output of the sensor is monitored for anomalies. Diagnosis and repair of identified defects may then follow.

A marine outboard motor having an internal combustion engine is provided. The internal combustion engine includes an engine block having at least one cylinder and a valve train comprising a cam, a valve assembly including a valve spring, a roller finger follower, and a pivot post. The pivot post extends from a fixed body of the engine block and defines a contact surface about which the roller finger follower pivots when deflected by the cam during use. The pivot post is moveable relative to the fixed body in a first longitudinal direction (A) against the action of the valve spring. A removable shim is disposed between the fixed body and a portion (182) of the pivot post to space the pivot post from the fixed body in the first longitudinal direction (A) and thereby reduce an amount of lash between the cam and the roller finger follower. The removable shim is dimensioned to fit at least partly around a shaft portion of the pivot post.

A valve opening and closing timing control device includes a drive-side rotating body that rotates synchronously with a crankshaft of an internal combustion engine, a driven-side rotating body that rotates with a camshaft of the internal combustion engine, an electric motor that controls a relative rotation phase of the drive-side rotating body and the driven-side rotating body, a motor control unit that controls a current supplied to the electric motor, a current sensor that detects the current flowing into the electric motor, a regulation unit that determines a regulation phase in which the relative rotation phase is mechanically limited in an advanced angle direction and in a delayed angle direction, and a regulation phase detection unit that detects the regulation phase based on when the relative rotation phase in which a change is stopped by the regulation unit is reached and a current value detected by the current sensor increases.

A valve opening and closing timing control device includes a drive-side rotating body that rotates synchronously with a crankshaft of an internal combustion engine, a driven-side rotating body that rotates with a camshaft of the internal combustion engine, an electric motor that controls a relative rotation phase of the drive-side rotating body and the driven-side rotating body, a motor control unit that controls a current supplied to the electric motor, a current sensor that detects the current flowing into the electric motor, a regulation unit that determines a regulation phase in which the relative rotation phase is mechanically limited in an advanced angle direction and in a delayed angle direction, and a regulation phase detection unit that detects the regulation phase based on when the relative rotation phase in which a change is stopped by the regulation unit is reached and a current value detected by the current sensor increases.

An internal combustion engine includes a cam-actuated rocker arm assembly with a solenoid-actuated latch that provides for cylinder deactivation or variable valve actuation. The solenoid has an inductance that varies significantly in relation to the position of a latch pin as it translates between latching and non-latching configurations. A sensor is positioned to monitor a current or a voltage in a circuit that includes the solenoid. Diagnostic information relating to the operation of the rocker arm assembly is determined by comparing data collected from the sensor over a first period to data collected from the sensor over a second period.

A marine outboard motor having an internal combustion engine is provided. The internal combustion engine includes an engine block having at least one cylinder and a valve train comprising a cam, a valve assembly including a valve spring, a roller finger follower, and a pivot post. The pivot post extends from a fixed body of the engine block and defines a contact surface about which the roller finger follower pivots when deflected by the cam during use. The pivot post is moveable relative to the fixed body in a first longitudinal direction (A) against the action of the valve spring. A removable shim is disposed between the fixed body and a portion (182) of the pivot post to space the pivot post from the fixed body in the first longitudinal direction (A) and thereby reduce an amount of lash between the cam and the roller finger follower. The removable shim is dimensioned to fit at least partly around a shaft portion of the pivot post.

In one embodiment, a method is provided. The method includes receiving a signal representative of an engine vibration transmitted via a knock sensor, wherein the knock sensor is disposed in an engine. The method additionally includes deriving a valve wear measurement during operation of the engine based on the signal. The method further includes communicating the valve wear measure.

A method of setting a tappet in an engine. The method includes setting a crankshaft at a predetermined crankshaft rotation angle. A cam coupled to the crankshaft is configured to provide cam lobe lift when the crankshaft is set at the predetermined crankshaft rotation angle. The cam lobe lift translates a tappet screw, coupled to the cam, towards a valve by a distance less than a gap defined between the valve and the tappet screw. The method also includes adjusting the tappet screw such that a zero gap tappet clearance is defined between the valve and the tappet screw.

An engine servicing system includes a motorcycle that has an engine. The engine has a cylinder head, an intake valve and an exhaust valve. A mount is provided and the mount is selectively coupled to the cylinder head. A plurality of bolts is provided and each of the bolts extends through the mount and engages the cylinder head at predetermined points on the cylinder head to retain the mount on the cylinder head. A compression unit is provided and the compression unit is removably coupled to the mount. The compression unit engages each of the intake valve and the exhaust valve such that the compression unit selectively compresses each of the intake valve and the exhaust valve. In this way each of the intake valve and the exhaust valve may be serviced while the engine is mounted in the motorcycle and without removing the cylinder head from the engine.