Description & Operation: Camshafts

This engine is a dual overhead camshaft (DOHC) type, which means there are 2 camshafts. One camshaft operates intake valves, and other camshaft operates exhaust valves. The camshafts sit in journals in cylinder head on top of engine. They are held in place by camshaft caps. The camshaft journals of cylinder head are drilled for oil passages. Engine oil travels to camshafts under pressure where it lubricates each camshaft journal. The oil returns to oil pan through drain holes in cylinder head. The camshaft lobes are machined into solid camshaft to open and close intake and exhaust valves, precisely correct amount, at precisely correct time. The camshaft lobes are oiled by splash action from pressurized oil escaping from camshaft journals.