Thus the spring holds the end of the push rod at all times against the periphery of the cam.
This push rod, in some instances, is a small bar of special steel that slides in guides of long-wearing bearing alloy.
The valves are operated through a push rod and rocker arm construction, which is 7⁄16′′ and exceedingly light.
This is primarily intended for taking up any wear that may occur at the ends of the push rod or valve stem.
Stiffening the spring, however, will be of but little help if the stem or push rod is tight in the guides through which it slides.
A spring of extremely large diameter returns the valve; a second spring located at the cylinder base handles the push rod linkage.
The cam and push rod design is extremely ingenious and the whole valve construction turns out very light.