Ti-VCT cam phasers · Focus Mk3, opened up

Vane rotors: fixed to each camshaft, turned against the sprocket by oilOil in the advance and retard chambersDegree wheel: ● intake opens · ○ exhaust closes · the arc between is overlapThe 1.6 Ti-VCT (1596 cc, 79 × 81.4 mm, belt-driven twin cams on bucket tappets) can turn each camshaft against its sprocket while running. Inside each sprocket a vane rotor bolted to the cam sits in oil chambers; an oil control valve sends engine oil to one side of the vanes or the other, so the cam advances or retards and the valves open earlier or later. At idle both phasers sit parked on their stopper pins with the valves barely overlapping. At part load the exhaust cam is retarded to hold some exhaust in the cylinder (less pumping loss, less NOx); at full load in the mid range the intake is advanced and overlap is greatest; near the red line overlap shrinks again. Ranges follow the axes of Ford's published Ti-VCT timing maps (intake opening from 20° after to 30° before TDC); the map in between is an illustration of the behaviour Ford describes, not Ford's calibration. The engine is drawn 120× slower than real.

Interactive figures of a Ford Focus Mk3 sedan (C346, 1.6 Ti-VCT, PowerShift automatic). Drawn with the MIT-licensed anatomy isometric kit. Not affiliated with Ford.