Depending on its design, a universal joint can accommodate a large angular variation between its inputs and outputs. This speed fluctuation increases with the angular difference between the shafts. V Valve float A high-rpm engine condition in which the valve lifters lose contact with the cam lobes because the valve springs are not strong enough to overcome the momentum of the various valvetrain components. The onset of valve float prevents higher-rpm operation. Extended periods of valve float will damage the valvetrain.
Most valve lifters have an oil-lubricated hardened face that slides on the cam lobe.
The collection of parts that make the valves operate. Viscous coupling A particular kind of fluid coupling in which the input and output shafts mate with thin, alternately spaced discs in a cylindrical chamber. The chamber is filled with a viscous fluid that tends to cling to the discs, thereby resisting speed differences between the two shafts. Viscous couplings are used to limit the speed difference between the two outputs of a differential, or between the two axles of a car. A valve used to limit the boost developed in a turbocharger .