Tecumseh Products Company

Gar M Adams

Erik J Christiansen

Roberto Molina

James W Moorman

Thomas A Immel

Kyle I Kubista

Rodney J Balzar

A drive train for an overhead valve engine, including a cam gear driven by the crankshaft, the cam gear supported for rotation in the cylinder block externally of the cylinder head and having a cam lobe mounted thereon for actuating a pair of rocker arms mounted for rotation in the cylinder head, which in turn actuates intake and exhaust valves in the cylinder head. A first lubrication passageway is provided in the crankcase of the engine to communicate oil, pumped from the oil sump by a combination oil pump and governor assembly driven from the crankshaft, to the upper crankshaft bearing. A second lubrication passageway is provided in the crankshaft and communicates oil from the upper crankshaft bearing to the coupling between the crankshaft and the connecting rod. An air cleaner body includes an integrally formed fitting extending therefrom, which fits within an opening in the breather cover to directly communicate the breather chamber with the air cleaner, wherein the air cleaner body may be mounted to the cylinder block in an easy, one-step operation in which the fitting is inserted into the breather cover opening and the air cleaner body is fastened directly to a mounting flange of the carburetor.

Mid cam engine

A drive train for a four stroke, overhead cam engine is provided, comprising a crankshaft, connecting rod, and piston assembly for reciprocating the piston within the cylinder bore of a cylinder block. An internally profiled cam gear is driven around an axis perpendicular to the axis of the cylinder block. A pair of follower arms extend from a pair of rocker arms and engage the cam profile to actuate intake and exhaust valves in the cylinder block. An intermediate gear is driven by the crankshaft at half speed to drive the cam gear, and may also be used to drive an additional device, such as a combination oil pump and governor. The cam follower arms may be disposed in an overlapping crosswise arrangement generally parallel to the cam gear, or may be disposed perpendicular to the cam gear.

Drive train for overhead cam engine

An overhead cam engine with a drive train including a crankshaft, connecting rod, and piston assembly for reciprocating the piston within the cylinder bore of a cylinder block. A cam ring rotates on the same axis as that along which the piston reciprocates, and has lobes on its upper surface for periodically actuating a pair of rocker arms which open and close intake and exhaust valves located within the cylinder head. The cam ring is driven at half speed by the crankshaft through a gear train arrangement including a timing shaft disposed on an axis parallel to the piston axis with gears at both ends for connecting the crankshaft with the cam ring.

Overhead ring cam engine with angled split housing

A single cylinder, internal combustion engine with a dry sump lubrication system. The engine includes an engine housing in which the overhead camshaft and crankshaft are rotatably supported, and the housing includes an integrally formed cylinder and head. A timing belt disposed externally of the engine housing interconnects the crankshaft and camshaft, and a piston connected to the crankshaft reciprocates within an internal bore provided in the engine housing cylinder. The cylinder wall around the internal bore is of a generally uniform thickness and circumscribed by cooling fins such that the cylinder resists bore distortion during operation. Dry sump lubrication is obtained by an external oil reservoir connected to a pump which supplies pressurized oil to the bearing journals of the camshaft. A portion of the oil at the camshaft bearing journals flows through passages provided within the cylinder to lubricate the bearing journals of the crankshaft. The reciprocating motion of the valve assemblies controlling intake and exhaust of the combustion chamber pumps the oil which lubricated the camshaft back to the external reservoir. The reciprocating motion of the piston similarly effects a high pressure within the crankcase cavity to pump oil which has lubricated the crankshaft back to the external reservoir. The inventive engine further provides for the mounting of flywheels within the crankcase cavity in conjunction with an external, lightweight fan for engine housing cooling, as well as employs a cast in valve seat for the overhead valve assemblies.

Overhead cam engine with cast-in valve seats

Overhead cam engine with integral head

A single cylinder, internal combustion engine with an engine housing in which the overhead camshaft and crankshaft are rotatably supported. The housing includes an integrally formed cylinder and head. A timing belt disposed externally of the engine housing interconnects the crankshaft and camshaft, and a piston connected to the crankshaft reciprocates within an internal bore provided in the engine housing cylinder. The cylinder wall around the internal bore is of a generally uniform thickness and circumscribed by cooling fins such that the cylinder resists bore distortion during operation. The inventive engine further provides for the mounting of flywheels within the crankcase cavity in conjunction with an external, lightweight fan for engine housing cooling, as well as employs a cast in valve seat for the overhead valve assemblies.

Overhead vertical camshaft engine with external camshaft drive

Overhead cam engine with dry sump lubrication system

A cast cylinder for an internal combustion engine having an intake valve cavity located on one side of the piston bore, an intake bore for communication with a carburetor located on the other side of the piston bore, and an internal passageway cast therein communicating the intake bore and the intake valve cavity. The internal passageway is curved and circumscribes a portion of the intake bore. A walled hollow tube having initially closed ends is embedded in the cast cylinder during casting as a permanently retained casting core. Subsequently the ends of the embedded tube are machined open to communicate with the intake valve cavity and the intake bore, respectively, to define the internal passageway.

Method of making a cast engine cylinder having an internal passageway

Cast engine cylinder having an internal passageway and method of making

Method and apparatus for counterbalancing an internal combustion engine while maintaining a lubricant flow path for supplying lubricant to a crankshaft connecting rod journal is disclosed wherein a generally cylindrical mass of crankshaft material is removed from a region of the crankshaft located coaxial with the connecting rod journal for engine balancing purposes with that removed mass including a portion of the lubricant passageway which supplies lubricant to the connecting rod journal. The region is then bridged by a tubular lubricant conduit to re-establish the lubricant path to the journal. Preferably the lubricant conduit is tubular and press fit into the existing passageway portions on opposite sides of the region with the lubricant passageway typically being a hole of uniform circular cross section extending oblique to the crankshaft axis of rotation and with the hole inside diameter substantially matching the outside diameter of the tube.

Lubrication scheme for pressure lubricated crankshafts with

A vented fuel reservoir filler cap having a check valve positioned intermediate an inner surface of that cap and an annular gasket seated in the cap so that both the gasket and check valve will in turn be captured between the cap inner surface and the fuel reservoir filler when the cap is in the reservoir closing position is disclosed with the check valve comprising a disc-like support with an elongated valve cavity carried by the support and having openings near opposite ends thereof with a valve member captive within the valve cavity and movable between a position near one cavity end for closing the valve and a position near the other cavity end allowing the valve to remain open. The spit resistant characteristics of the cap are enhanced by providing a baffle intermediate the check valve and an aperture in the fuel cap for venting the reservoir and may be further enhanced by providing another baffle on the side of the check valve opposite the first baffle. Inadvertent inversion of the reservoir allows the valve member to move into a valve closing position minimizing leakage from the cap aperture.

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Elkhart Lake, WI, United States of America

Gar M Adams