C9.3B Engines Caterpillar

Finding Top Center Position for No. 1 Piston

Usage:

D6 B72

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Table 1
Required Tools
Tool	Part Number	Part Name	Qty
A	139-7063	Timing Pin Adapter	1
B	136-4632	Timing Pin	1
C⁽¹⁾	9S-9082 (Turning Port Tool) 208-0888 (Turning Port Tool) 350-7549 (Damper Turning Tool) 5P-7305 (Starter Turning Tool) 5P-7306 (Starter Turning Tool)	Engine Turning Tool	1

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⁽¹⁾	The tool that is required for turning the engine over will be determined by the flywheel housing and application.

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Illustration 1	g01167315
Flywheel housing (1) Timing hole

Remove the plug from timing hole (1) and install Tool (B) in the timing hole on the flywheel housing. Tool (C) can be used for turning the flywheel in the flywheel housing. Turn the flywheel in the direction of engine rotation. The direction of engine rotation is counterclockwise, as the engine is viewed from the flywheel end. Turn the flywheel until the timing pin engages with the threaded hole in the flywheel.
Note: If the flywheel is turned beyond the point of engagement, the flywheel must be turned in the direction that is reverse of normal engine rotation. Turn the flywheel by approximately 30 degrees. Then turn the flywheel in the direction of normal rotation until the timing pin engages with the threaded hole. This procedure eliminates the backlash from the gears when the No. 1 piston is at the top center position.
Remove the front valve mechanism cover from the engine.
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.
Note: When the actual stroke position is identified, and the other stroke position is needed, remove the timing bolt from the flywheel. Then turn the flywheel by 360 degrees in the direction of normal engine rotation and reinstall the timing bolt.