Engine valve lifters, 1, are assembled into a guide, 2, for shipping and installation into an engine block. This guide has the additional purpose of maintaining the cam shaft lobe to lifter roller alignment while the engine is running. There have been instances, with the current anti-rotation measures built into the lifter and guide, 3,4, where the lifters have rotated in the litter bore of the engine block causing major damage to the engine. A way to increase the torque required to rotate the valve lifter in the lifter guide is adding recesses with associated sharp edges to the outside of the lifter to guide contact point, 5-9. This contact edge is most effective when the lifter is used with a non-metal or nylon guide. The relative softness of these guides, especially at operating engine temperalures, creates an extra moment force because the sharp edge of the lifter body "bites" into the guide material, 10. Testing has shown greater than 50% increase in torque needed to rotate a lifter in the guide socket.
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