GEAR (12 TEETH-DRIVE) 4M0504 - Caterpillar

The No. 1 cylinder is at the Top Center position on the compression stroke.
The crankshaft timing pin is engaged in the bracket which is attached to the crankshaft.
The camshaft timing pin is engaged in the hole in the camshaft assembly. For Vee engines, both of the camshaft timing pins must be engaged.Note: Always prelube the engine when you rotate the crankshaft.The switch for the engine prelube is located on the remote control panel. The switch enables manual lubrication of the engine.DO NOT use the starting motor to rotate the crankshaft. If the crankshaft is rotated too fast, lubrication with the prelube pump is not sufficient for protecting the engine.Use the manual barring group to rotate the crankshaft for service work. Keep the prelube pump running when the crankshaft is rotated. Damage can result if the crankshaft is rotated on dry bearing surfaces.
Illustration 1 g00311103
(1) Barring device
(2) Storage position for the timing pin
Remove the timing pin from storage position (2) that is located below barring device (1).
Illustration 2 g00311105
Installation of the timing pin
(3) Timing bracket
(4) Mounting bracket for the timing pin
(5) Timing pin
Operate the prelube pump. Use the barring device to turn the flywheel in the direction of normal engine rotation. Turn the flywheel until timing pin (5) can be installed through bracket (4) into timing bracket (3). Note: If the flywheel is turned beyond the point of installation in timing bracket (3), the play must be removed from the timing gears. Turn the flywheel in the opposite direction of normal rotation for approximately 20 degrees. Then turn the flywheel in the direction of normal engine rotation until the timing pin can be installed.
Remove the valve cover from the No. 1 cylinder head.
The inlet and exhaust valves for the No. 1 cylinder are fully closed if No. 1 piston is on the compression stroke and the rocker arms can be moved by hand. If the rocker arms cannot be moved and the valves are slightly open, the No. 1 piston is on the exhaust stroke. For the cylinders to service according to the corresponding crankshaft position, refer to Testing and Adjusting, "Crankshaft Positions for Valve Lash Setting". Note: When the actual stroke position is identified and the other stroke position is needed, remove the timing pins from the engine. Turn the flywheel for 360 degrees in the direction of normal engine rotation.