An anti-rotation guide for preventing rotation of a roller follower valve
lifter in an internal combustion engine. The guide has an outer surface
for engaging an engine bore and an inner surface for slidably receiving
the lifter. One end of the guide includes an anti-rotation feature for
cooperating with a mating feature on the lifter, preferably flats
although other configurations are contemplated within the scope of the
invention. The anti-rotation feature may take any of a plurality of
shapes, including but not limited to an arm and tang, a flap, and an
orifice flat. The guide is installed from an opening in the engine bore
proximate a camshaft disposed in the engine block. The cooperating
features prevent axial rotation of a lifter within the sleeve but do not
inhibit axial or reciprocal motion of the lifter.