Side-Valve operation – The side valve engine still has a camshaft, which opens and closes the valves in a timed sequence. As the camshaft moves around the lobes push the tappets up, which in turn pushes the valve stem unlike the OHV engine design, the OHV has rockers which use leverage to open the valves. The Side Valve design directly moves the valve open and closed. The valve springs pressure closes the valves port.

Image Copyright © Nicholas Seal. Do not copy.