C12.9 Marine Propulsion Engine Caterpillar

Specifications

Introduction

Use this procedure to check and/or adjust the camshaft and flywheel timing.

Required Tools

Camshaft Timing Procedure

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Illustration 1	g06169232

1. Find the top center position for the number one piston. Refer to Testing and Adjusting, "Finding Top Center Position for No. 1 Piston".
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   Illustration 2	g06178242

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   Illustration 3	g06178273

2. Fit the camshaft (4), positioning it with the reference marks (⇒) as shown in the Illustration ( (7), front view of engine).

3. Lubricate the seal ring and fit it onto the shoulder plate (9).

4. Fit the shoulder plate (9) with the sheet metal gasket (8).
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   Illustration 4	g06178319

5. Tighten the screws (1 to 10).
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   Table 4

   Number	Description	Tightening Torques
   5	M8X1.25 Screws
   	Step 1	20 ± 2 N·m (14.8 ± 1.48 lb ft)
   	Step 2	20 ± 2 N·m (14.8 ± 1.48 lb ft)

   Note: Tighten the screws in the order indicated in table:

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   Table 5

   Tightening Sequence
   Step 1	1-2-3-4-5
   Step 2	6-7-8-9-10

Fitting Second Idler Gear

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Illustration 5	g06178327

1. Apply 487-3144 Gauge (1).

2. Check and adjust the position of the connecting rod (3) for the transmission gear. Tighten the screw (2) to the specified torque.
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   Illustration 6	g06178334

3. Refit the transmission gear (4) and lock the screws (5) to the required torque.
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   Table 6

   Number	Description	Tightening Torques
   3	M8X1.25 Screws
   	Step 1	30 mm (1.2 inch)
   	Step 2	30 mm (1.2 inch)

   Note: Lubricate the screws (2) with engine oil before assembly.

Fitting gear on Camshaft

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Illustration 7	g06178340

1. Position the gear (2) on the camshaft so that the 4 slots are centered with the holes for fixing the camshaft, without fully locking the screws (5).

   Note: Lubricate the screws (5) with engine oil before assembly.

2. With a magnetic dial gauge (1) check clearance between the gears (2) and (3), which must be between 0.074 - 0.195 mm, otherwise adjust the clearance as indicated below.

3. Loosen the screws (4) securing the transmission gear (3).

4. Loosen the screw (2) securing the connecting rod, move the connecting rod (3) to obtain the required clearance.

5. Lock the screw (2) securing the connecting rod and the screws (4) securing the transmission gear to the prescribed torque.