Abstract: Air intake systems having filters are useful for removing airborne particles from the air flow. When two filters are used in two separate air systems, one of the filters could become restricted before the other and require more frequent service. The subject air intake arrangement includes a balance tube connected between a first air supply and a second air supply to balance the rate at which the filters become restricted. This arrangement of components will tend to draw more air through the cleaner filter until it is restricted the same degree as the other filter.

Abstract: A multi-fuel engine is capable of running on lead free gasoline, leaded gasoline, and liquid propane. The engine has a valve seat and an exhaust valve. The valve seat has a seating surface. The exhaust valve has an axis, a seating face, and is of dimensions sufficient for seating of the valve on the valve seat. The seating surface has a width in a range of about 2.30 to about 2.90 millimeters and defines an included angle in a range of about 110.degree. to about 130.degree. relative to the axis of the exhaust valve. Apparatus forcibly urges the seating face against the seating surface at a force in a range of about 200 to about 245 Newtons.

Abstract: In an engine having an elongated block terminating at one end in a flywheel housing, a flywheel with at least one timing mark on its periphery and rotatable within the housing, and spaced lifting eyes secured to the engine so that the engine may be lifted from a support, the improvement wherein the flywheel housing has an opening in its generally uppermost surface through which the timing mark may be viewed and one of the lifting eyes includes a base defining a closure for the opening. Bolts removably secure the base to the flywheel housing about the opening to (a) close the opening and (b) secure the lifting eye to the engine.

Abstract: A bolt-on exhaust brake for an internal combustion engine includes a damper movable to open and closed positions, and an air cylinder actuatable to move the damper to its closed position. The damper is openable upon back-pressure reaching 30 psi, so as to avoid damage to the engine.

Abstract: An exhaust gas recirculation system is provided for reducing the content of oxides of nitrogen in the exhaust of a diesel engine. The system is effective in recirculating variable amounts of exhaust gas back through the engine in relation to engine load by being operatively controlled in response to predetermined settings of the engine's fuel supply system.