A variable timing camshaft drive assembly for an internal combustion
engine utilizes a single cam phaser, driven by an engine crankshaft,
capable of operating multiple camshafts carried on multiple banks of an
engine. The cam phaser is carried on a hub extending from a mounting
member attached to an engine block. The cam phaser includes an input
sprocket and an output sprocket separated by a phasing device capable of
altering the phase angle of the sprockets relative to one another. A
first timing chain connects a drive sprocket of the crankshaft with the
input sprocket of the cam phaser and a second timing chain connects the
output sprocket of the cam phaser with the driven sprockets of the
camshafts. As the phasing device alters the phase angle between the input
and output sprockets, the phase angle between the camshafts and the
crankshafts is altered.