a single journal bearing replaces three bearings in applications where one arm is rotary supported by the inner diameter bearing surface of the journal bearing and another arm is rotary supported by the outer diameter of the bearing surface and the journal bearing is fixed so that it cannot rotate . in a v - shaped piston engine the female piston rod is rotary supported to the inner diameter of the journal bearing for driving the shaft crank journal affixed to the fly wheel and the male piston rod is rotary supported for articulated motion to the outer diameter of the journal bearing . in another embodiment a roller bearing is mounted withing said journal bearing and serves to rotary support the shaft crank journal of the fly wheel .