Abstract: Apparatus for preventing cam walk in an automotive engine of the type including engine block with a cam shaft having one end extending from the block and coupled to the engine's crank shaft by a timing chain includes a timing chain cover fastened to the engine block and covering the cam shaft and the timing chain, with a thrust pin coupled between the cover and extending axial with the cam shaft. A low friction thrust button is adjustable fixed to the thrust pin, so as to permit adjustment of the dimension between the extremity of the cam shaft and the low friction bearing means, thereby reducing "cam walk" during high performance operation of the engine.The assembly may include a metal spacer interposed between the cover and the block.