Pic. 2.20. The valve mechanism of Mazda 6 car engines: 1 - camshaft; 2 - timing chain drive; 3 – an asterisk of a camshaft; 4 - tensioner lever; 5 - chain tensioner; 6 - crankshaft pulley; 7 - chain guide; 8 - valve assembly; 9 - cam; 10 - oil control valve (OCV); 11 - the actuator of the variable valve timing system
Each cylinder has two intake and two exhaust ports. 16 valves are directly actuated by two camshafts. Model L3 engines use a variable valve timing mechanism that provides the best timing for opening or closing the valves, depending on driving conditions, constantly changing the phases of the intake camshaft (pic. 2.20).
Pic. 2.21. Diagram of valve opening and closing of Mazda 6 engines: 1 - TDC; 2 - variable area; 3 - release; 4 - inlet; 5 - NMT