Abstract: According to the present invention there is provided a poppet valve assembly comprising a plurality of simultaneously operated poppet valve members slidably mounted for movement between their open and closed positions by their stems the axes of which are not all parallel, a rocker mounted for rocking movement about a rocking axis transverse to each valve stem axis, the rocker having a valve stem engaging tappet element for each valve for engaging an end face of the respective valve stem, the respective lengths of the valve stems, being such that the tappet elements are not all in the same plane through the rocker axis in such a manner that simultaneously for each valve, in an intermediate part of the valve lift travel, a line from the rocker axis to the point of engagement of the tappet element with the end face of the valve stem is perpendicular to the valve stem axis.

Abstract: A three-cylinder four-stroke internal combustion engine has first and third diametrically opposed pistons and a third piston arranged to reciprocate on an axis at right angles to that of the cylinders. A connecting link assembly is connected at its upper end to the second piston and at its lower end is slidably guided in the engine casing and carries a counterweight. The connecting link assembly has a central parallel sided transverse opening in which can slide a drive block rotatably mounted on a crankpin portion of the engine output shaft which has balance weights. The first and third pistons are interconnected by a further connecting link assembly which is connected to the crankpin in a similar manner. The first and third pistons reciprocate in quadrature with the second piston and the counterweight so that the combined effect of the reciprocating masses is one mass concentrated at the axis of the crankpin and thus readily balanced by the crankshaft balance weight.