HOUSING AS-REGULATOR 2555310 - Caterpillar

Illustration 1 g03682402
Timing Gears (A) Fuel injection pump drive gear (B) Idler gear (C) Camshaft gear (D) Crankshaft gear
The engine timing gears have a reference mark on each gear. The No. 1 cylinder is at the top center position when these marks are in alignment.Note: This engine is not timed with a pin and this engine has an idler gear with an odd number of teeth. Do not rotate the engine if the fuel injection pump is removed. The gears must be aligned by using the timing marks once the front housing is removed. Mark the teeth with a paint stick. Reinstall the fuel injection pump by meshing the marked teeth.
Illustration 2 g01412325
Fuel Injection Pump Timing Mark (1) Timing marks (2) Timing marks
Timing marks (1) and (2) on the fuel injection pump indicate the pump position relative to the timing gear. Each mark on the scale represents a change in timing of six degrees.
Turn the crankshaft until the No. 1 piston is approximately 60 degrees BTC on the compression stroke.Note: Check the valve lash with the No. 1 cylinder at the top center position. This ensures that the cylinder is on the compression stroke and that the cylinder is not on the exhaust stroke.
Illustration 3 g00565561
Crankshaft Pulley Timing Marks
The crankshaft pulley contains a scale that has a range of 0 degrees to 40 degrees. Each mark on the scale represents a 5 degree crankshaft rotation.