Abstract: A rotary car washing cell includes a platform for supporting an automotive vehicle and rotatably coupled to a base for rotating the vehicle about a fixed axis. The platform includes a guide rail disposed along a predetermined path on the platform. A support frame is fixedly secured to the base. A wash arm assembly for spraying fluid onto the vehicle is slidably supported by the support frame for radial movement with respect to the fixed axis. The wash arm assembly including a cam follower for engaging the guide rail during rotation of the platform, whereby the wash arm assembly is radially displaced with respect to the fixed axis in response to the rotation of the platform about the fixed axis.