TIMING GEAR
Multiple link primary and single row secondary chains drive the camshafts of each cylinder bank. The primary chains transmit drive from 2 sprockets on the crankshaft to each intake camshaft sprocket. The secondary chains transmit drive from the intake camshaft sprockets/variable valve-timing units, to the exhaust camshafts. A key locates the 2 drive sprockets on the crankshaft. The crankshaft's torsional vibration damper retains the sprockets in position. The intake camshaft/variable valve timing units and exhaust camshaft sprockets are non-interference, non-keyed fit on their respective camshafts; the drive being transmitted by the face-to-face friction load produced by the variable valve timing unit/sprocket-securing bolt. Each chain has a hydraulic tensioner operated by engine oil. The primary chains are lubricated via oil squirt tubes located at the front of the engine block, near the crankshaft drive sprockets. A jet of oil from the end of each secondary chain tensioner lubricates the secondary chains. The primary chain tensioners act on pivoting flexible tensioner blades. The secondary chain tensioners act directly on the chains. Guide rails are installed on the drive side of the primary chains.