Abstract: In variable displacement engines, a portion of the intake valves have deactivatable valve lifters. When the engine conditions are such that some of the cylinders are to be deactivated, the intake and/or exhaust valve lifters in those cylinders are deactivated. Operation of the mechanism inside the lifter that is actuated to deactivate the valves can be harmed when particles in the engine oil get inside. To prevent small particles entering the valve lifter, a small filter is provided just upstream of the orifice into which oil enters the valve lifter. In other embodiments, a wire mesh formed into a coil is inserted into the recess. In some applications, a cage with snap-fitting connectors is installed over the filter to keep the wire mesh in place and properly coiled. The cage also fits into the recess. Such filter may also be applied to a hydraulic lash adjuster feature in a lifter.