3034 Engine for Caterpillar Built Machines Caterpillar

Finding Top Center Position for No. 1 Piston

Usage:

3034 3NW

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Illustration 1	g00397597
Finding the top center position (1) Valve stem

Remove the valve mechanism cover.

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Illustration 2	g00397619
(2) Mark on crankshaft pulley (3) Mark on timing case

Rotate the crankshaft in a clockwise direction as you face the front of the engine. Rotate the crankshaft until the pushrod for the inlet valve of the rear cylinder begins to lift the rocker arm. The piston for the number one cylinder will be near to the top center position. The mark on crankshaft pulley (2) should be near to the mark on timing case (3) .

Remove the spring clip and the spacer from the front of the rocker shaft. Release the fasteners of the two front brackets of the rocker shaft. Loosen the screws for the valve lash adjustment. Remove the front rocker arm. Tighten the fasteners of the brackets on the rocker shaft.

Remove the valve spring from the front valve. Refer to Disassembly and Assembly, "Inlet and Exhaust Valve Springs - Remove and Install".
Note: Place a suitable collar near the top of the valve in order to hold the valve if the crankshaft is rotated too far. Use care in rotating the crankshaft. The number 1 inlet valve will be held in position on top of the piston. If the crankshaft is not properly positioned, the valve may fall from the cylinder head.

Fasten a dial indicator to the cylinder head. The plunger of the dial indicator must be in contact with the top of the valve stem (1). The dial indicator must indicate a reading which is greater than zero.

Rotate the crankshaft by approximately 45 degrees in a counterclockwise direction. Then, rotate the crankshaft in a clockwise direction until the gauge of the dial indicator reaches the most positive reading. The mark on crankshaft pulley (2) should be aligned with the mark on timing case (3). Number 1 piston is now at the top center on the compression stroke.