Electrical Observation of Lubricant Film Between a Cam and a Lifter of an OHV Engine

The paper describes an electrical method to observe formation and break down of a lubricant film between a cam and a lifter through electrical voltage (conductivity) variation.

Break down of the lubricant film increased with decreasing oil viscosity, increasing valve spring load and growth of pitts on the lifter surface. The process of film formation during running-in and cold start was also studied.

A computer-aided data processing system was developed to obtain the relations between the cam angle and the average electrical voltage across the lubricant film.