Use this procedure for adjusting valves on C12.9L engines.
| Parameter | Value |
|---|---|
| Inlet Valves | |
| Exhaust Valves | |
| Rocker arm adjustment nut | |
| Firing Order |
|---|
| 1-4-2-6-3-5 (1) |
| (1) | The No. 1 cylinder is at the front of the engine. |
Note: The valve lash must be checked and adjusted by the proper sequence shown above. Rotate the engine in direction of rotation.
| Qty | Part Number |
|---|---|
| 1 | 487-3130 Tool
487-3131 Spacer |
| 1 | 456-7990 Timing Pin
487-3141 Checking Fixture |
| 1 | 5801694399 |
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| Illustration 1 | g06169129 |
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Typical example of the 487-3130 Tool | |
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| Illustration 2 | g06169134 |
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Typical example of the 487-3131 Spacer | |
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| Illustration 3 | g03703217 |
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Typical example of the 456-7990 Timing Pin | |
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| Illustration 4 | g06169138 |
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Typical example of the 487-3141 Checking Fixture | |
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To prevent possible injury, do not use the starter to turn the flywheel. Hot engine components can cause burns. Allow additional time for the engine to cool before measuring valve clearance. |
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| Illustration 5 | g06169191 |
- Remove the flywheel speed sensor.
- Rotate the engine past flywheel marks "D" and "E" and stop at the next mark "B".
Refer to Testing and Adjusting, "Finding Top Center Position Number 1 Piston" for more information.
a. Hole on flywheel with reference mark, corresponding to the TDC of pistons 2-5.
b. Hole on flywheel with reference mark, corresponding to the TDC of pistons 1-6.
c. Hole on flywheel with reference mark, corresponding to the TDC of pistons 3-4.
d. Flywheel hole with two notches corresponding to position 54 degrees TDC of pistons 1-6. Camshaft timing reference.
e. Flywheel hole with three notches corresponding to position 30 degrees TDC of pistons 1-6. References to high-pressure fuel pump timing system and phonic wheel timing.
f. Flywheel holes before hole with three notches "anti-clock-wise rotation of flywheel" corresponding to position 36 degrees before TDC of pistons 1-6.
x. Flywheel frontal hole corresponding to position 15 degrees before TDC.
Adjustment of clearance between rocker arms and intake/exhaust valve control crosspieces must be performed with utmost care.
Bring to blast phase cylinder to be adjusted, the valves of this cylinder are closed while the symmetric cylinder valves are balanced. Symmetric cylinders are 1-6, 2-5, and 3-4.
To carry out the adjustments stated above, the sequence shown in the table is mandatory.
To perform adjustments correctly, during each rotation phase, check the positioning accuracy using the tool for TDC Engine 456-7990 Tool, inserting the tool into the hole marked with a notch on the flywheel corresponding to the position of the pistons.
| Firing Order 1-4-2-6-3-5 | |||
|---|---|---|---|
| Step | Start and Rotation Clockwise | Balance Valve of Cylinder No. | Adjust Clearance of Valves Cylinder No. |
| First | 1 and 6 at TDC | 6 | 1 |
| Second | Rotate 120 degrees | 3 | 4 |
| Third | Rotate 120 degrees | 5 | 2 |
| Fourth | Rotate 120 degrees | 1 | 6 |
| Fifth | Rotate 120 degrees | 4 | 3 |
| Sixth | Rotate 120 degrees | 2 | 5 |
Use the following procedure to adjust the valve lash:
Refer to Testing and Adjusting, "Finding Top Center Position Number 1 Piston" for more information.
- Adjust the clearance between the rocker arms and valves using a box wrench and feeler gauge (2).
- The operating clearance is:
Show/hide table
Table 5 Intake Valve 0.40 ± 0.05 mm (0.016 ± 0.002 inch) Exhaust Valve 0.60 ± 0.05 mm (0.024 ± 0.002 inch) - Use a polygonal spanner (2) to release lock nut (1) of rocker arm adjustment screw.
- Insert feeler gauge (3) having same value of operating clearance shown in Table 5.
- Use a suitable wrench to screw or unscrew rocker arm adjusting screw.
- Check that feeler gauge (3) slides with a low friction.
- Keeping the adjustment screw stationary, tighten the locking nut to a torque of:
Show/hide table
Table 6 Ref Qty Description Tightening Torque 1 12 M10X1.25 39 ± 5 N (8.7 ± 1.1 lb)
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| Illustration 6 | g06169145 |
After adjusting the valve clearance, end the assembly procedure by installing the head cover with the relevant seal.