Abstract: The invention relates to a hydraulic engine with radial pistons, comprising girders which transmit the thrusts of the pistons and rest against strips secured to the cylinder block.The surface of the cylinder block has a degree of roughness at least equal to the following values given in reference to the currently applied norms 0.25 .mu.RA; 15 .mu.Rt; and 8 .mu.Rp.The invention finds its application in the production of a reliable engine.

Abstract: The invention relates to an engine with radial pistons 9, which are coupled to elastic return means 25 for free-wheeling operation.Said elastic means are constituted by springs 25 whose number is equal to that of the pistons and by levers 21 mounted to pivot, each with respect to a piston 9, about an axis parallel to the axis of rotation 6 of the cylinder block 7, and equal in number to the springs, whereas each spring 25 is coupled to two levers 21, each lever constituting the bond for two springs 25.An application is the production of a hydraulic engine which is reliable and of simple design.