ALTERNATOR GP-CHARGING 4W1489 - Caterpillar

Illustration 1 g01134124
Front Gear Group
(1) Camshaft gear and timing reference gear
(2) Timing marks
(3) Idler gear
(4) Crankshaft gear Correct fuel injection timing and correct valve mechanism operation is determined by the timing reference gear and the alignment of the front gear group. The timing reference gear is located on the camshaft gear. The timing reference gear is used to measure crankshaft rotation. During installation of the front gear, timing marks (2) on idler gear (3) must be in alignment with the timing marks on crankshaft gear (4) and the timing marks on camshaft gear (1). Check the teeth on the timing reference gear. The teeth should not be defaced. The teeth should have sharp clean edges and the teeth should be free of contaminants.Note: The electronic injection timing must be calibrated after reassembly of the front gear train.