C15 and C18 Tier 4 Final Engines Engine Valve Lash - Inspect/Adjust Caterpillar

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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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This engine uses high voltage to control the fuel injectors. Disconnect electronic fuel injector enable circuit connector to prevent personal injury. Do not come in contact with the fuel injector terminals while the engine is running.

Specifications

Introduction

Use the procedure below to inspect and adjust the valve mechanism lash settings.

Note: Valve lash is measured between the rocker arm and the valve bridge. All measurements and adjustments must be made with the engine stopped and the valves fully closed.

References

Reference: Testing and Adjusting, Finding Top Center Position No. 1 Piston

Reference: Disassembly and Assembly

Mechanical Electronic Injector Unit (MEIU) and Valve Lash Adjustment Procedure

1. Put the number 1 piston at Top Dead Center (TDC) on the compression stroke. Refer to the Testing and Adjusting, Finding Top Center Position No. 1 Piston.

   Note: To check that the number 1 piston is on TDC, both the inlet and exhaust valves on cylinder number 1 will move freely. If the valves do not move freely, cylinder number 1 is on TDC of the exhaust stroke. Install the timing pin in the flywheel.

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   Table 5

   TDC No. 1 Compression Stroke	Inlet Valves	Exhaust Valves
   Valve Lash	C13 0.38 ± 0.08 mm (0.015 ± 0.003 inch) C15 and C18 0.38 ± 0.08 mm (0.015 ± 0.003 inch)	C13 0.76 ± 0.08 mm (0.030 ± 0.003 inch) C15 and C18 0.81 ± 0.08 mm (0.032 ± 0.003 inch)
   Cylinders	1–2–4	1–3–5

2. Adjust the valve lash using the specifications from Table 5.

   1. Lightly tap the rocker arm with a soft mallet.

      Note: This ensures that the roller lifter seats against the base circle of the camshaft.

   2. Loosen the adjustment locknut for the appropriate valves.

   3. Place the feeler gauge between the rocker arm and the valve bridge.

   4. Turn the adjustment screw in a clockwise direction while sliding the feeler gauge back and forth between the rocker arm and valve bridge. Continue turning the adjustment screw in a clockwise direction until a slight drag is felt on the feeler gauge.

   5. Tighten the adjustment locknut to 30 ± 7 N·m (22 ± 5 lb ft).

      Note: Do not allow the adjustment screw to turn while torquing the locknut.

   6. Recheck the valve lash after tightening the adjustment locknut. Remove the feeler gauge.

3. Follow the steps below to set the mechanical unit injectors on TDC of number 1 piston compression stroke.

   Note: Injectors for cylinders 3, 5, and 6 can be adjusted at TDC of number 1 piston compression stroke.

   1. Loosen the adjustment locknut for the injector.

   2. Turn the adjustment screw clockwise until the screw contacts the mechanical electronic unit injector.

   3. Turn the adjustment screw an extra two turns clockwise to push all the fuel out of the injector plunger.

      Note: The additional turns will ensure the injector pre-load is set accurately.

   4. Turn the adjustment screw counter-clockwise for 2.5 turns.

   5. Turn the adjustment screw clockwise until the screw contacts the injector.

   6. Turn the screw clockwise an extra 180 degrees or half turn.

   7. Tighten the locknut to 55 ± 10 N·m (41 ± 7 lb ft) while not allowing the adjustment screw to turn for C13 engines. Tighten the locknut to 100 ± 10 N·m (74 ± 7 lb ft) while not allowing the adjustment screw to turn for C15 and C18 engines

4. Remove the timing pin and rotate the engine 360 degrees in the direction of engine rotation. This will put the engine at TDC of number 6 piston. Pin the flywheel with the timing pin.

   Note: To check that the number 1 piston is on TDC, both the inlet and exhaust valves on cylinder number 6 will move freely. If the valves do not move freely, cylinder number 6 is on TDC of the exhaust stroke. Install the timing pin in the flywheel.

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   Table 6

   TDC No. 6 Compression Stroke	Inlet Valves	Exhaust Valves
   Valve Lash	C13 0.38 ± 0.08 mm (0.015 ± 0.003 inch) C15 and C18 0.38 ± 0.08 mm (0.015 ± 0.003 inch)	C13 0.76 ± 0.08 mm (0.030 ± 0.003 inch) C15 and C18 0.81 ± 0.08 mm (0.032 ± 0.003 inch)
   Cylinders	3–5–6	2–4–6

5. Adjust the valve lash using the specifications from Table 6.

   1. Lightly tap the rocker arm with a soft mallet.

      Note: This ensures that the roller lifter seats against the base circle of the camshaft.

   2. Loosen the adjustment locknut for the appropriate valves.

   3. Place the feeler gauge between the rocker arm and the valve bridge.

   4. Turn the adjustment screw in a clockwise direction while sliding the feeler gauge back and forth between the rocker arm and valve bridge. Continue turning the adjustment screw in a clockwise direction until a slight drag is felt on the feeler gauge.

   5. Tighten the adjustment locknut to 30 ± 7 N·m (22 ± 5 lb ft).

      Note: Do not allow the adjustment screw to turn while torquing the locknut.

   6. Recheck the valve lash after tightening the adjustment locknut. Remove the feeler gauge.

6. Follow the steps below to set the mechanical unit injectors on TDC of number 6 piston compression stroke.

   Note: Injectors for cylinders 1, 2, and 4 can be adjusted at TDC of number 6 piston compression stroke.

   1. Loosen the adjustment locknut for the injector.

   2. Turn the adjustment screw clockwise until the screw contacts the mechanical electronic unit injector.

   3. Turn the adjustment screw an extra two turns clockwise to push all the fuel out of the injector plunger.

      Note: The additional turns will ensure the injector pre-load is set accurately.

   4. Turn the adjustment screw counter-clockwise for 2.5 turns.

   5. Turn the adjustment screw clockwise until the screw contacts the injector.

   6. Turn the screw clockwise an extra 180 degrees or half turn.

   7. Tighten the locknut to 55 ± 10 N·m (41 ± 7 lb ft) while not allowing the adjustment screw to turn for C13 engines. Tighten the locknut to 100 ± 10 N·m (74 ± 7 lb ft) while not allowing the adjustment screw to turn for C15 and C18 engines

7. Reinstall the timing pin cover and valve covers. Refer to the Disassembly and Assembly manual.

Variable Valve Actuator and Compression Brake Lash Adjustment Procedure (If Equipped)

1. Adjust the compression brake lash using the specifications from Table 7.

   1. Loosen the adjustment screw locknut. Turn the screw clockwise until contact is made with the exhaust rocker arm.

   2. Turn the adjustment screw counter-clockwise two full turns or until the compression brake rod is no longer contacting the exhaust rocker arm.

      Note: This process will ensure that all the oil is out of the cylinder for the compression brake.

   3. Install the feeler gauge between the brake piston and the exhaust rocker arm.

   4. Turn the adjustment screw clockwise while sliding the feeler gauge back and forth between the brake piston and rocker arm. Continue turning the adjustment screw in a clockwise direction until a slight drag is felt on the feeler gauge.

   5. Leave the feeler gauge between the brake piston and rocker arm. Tighten the adjustment locknut to 15 ± 3 N·m (11 ± 2 lb ft).

      Note: Do not allow the adjustment screw to turn while torquing the locknut.

   6. Recheck the valve lash after tightening the adjustment locknut. Remove the feeler gauge.
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      Table 8

      Top Dead Center (TDC) No. 6 Piston Compression Stroke
      Variable Valve Actuator (VVA) Lash	C15 and C18 0.50 ± 0.08 mm (0.020 ± 0.003 inch)
      Cylinders	3–5–6

2. Adjust the VVA lash using the specifications from Table 8.

   1. Loosen the adjustment screw locknut. Turn the screw clockwise until contact is made with the inlet rocker arm.

   2. Turn the adjustment screw counter-clockwise two full turns or until the VVA rod is no longer contacting the inlet rocker arm.

      Note: This process will ensure that all the oil is out of the cylinder for the VVA.

   3. Install the feeler gauge between the actuator piston and the inlet rocker arm.

   4. Turn the adjustment screw clockwise while sliding the feeler gauge back and forth between the actuator piston and rocker arm. Continue turning the adjustment screw in a clockwise direction until a slight drag is felt on the feeler gauge.

   5. Leave the feeler gauge between the actuator piston and rocker arm. Tighten the adjustment locknut to 50 ± 10 N·m (37 ± 7 lb ft).

      Note: Do not allow the adjustment screw to turn while torquing the locknut.

   6. Recheck the valve lash after tightening the adjustment locknut. Remove the feeler gauge.

3. Remove the timing pin and rotate the engine 360 degrees in the direction of engine rotation. This will put the engine at TDC of number 1 piston. Pin the flywheel with the timing pin.
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   Table 9

   Top Dead Center (TDC) No. 1 Piston Compression Stroke
   Compression Brake Lash	C13 0.711 ± 0.05 mm (0.028 ± 0.002 inch) C15 and C18 0.686 ± 0.05 mm (0.0270 ± 0.002 inch)
   Cylinders	1–3–5

4. Adjust the compression brake lash using the specifications from Table 9.

   1. Loosen the adjustment screw locknut. Turn the screw clockwise until contact is made with the exhaust rocker arm.

   2. Turn the adjustment screw counter-clockwise two full turns or until the compression brake rod is no longer contacting the exhaust rocker arm.

      Note: This process will ensure that all the oil is out of the cylinder for the compression brake.

   3. Install the feeler gauge between the brake piston and the exhaust rocker arm.

   4. Turn the adjustment screw clockwise while sliding the feeler gauge back and forth between the brake piston and rocker arm. Continue turning the adjustment screw in a clockwise direction until a slight drag is felt on the feeler gauge.

   5. Leave the feeler gauge between the brake piston and rocker arm. Tighten the adjustment locknut to 15 ± 3 N·m (11 ± 2 lb ft).

      Note: Do not allow the adjustment screw to turn while torquing the locknut.

5. Recheck the valve lash after tightening the adjustment locknut. Remove the feeler gauge.
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   Table 10

   Top Dead Center (TDC) No. 1 Piston Compression Stroke
   Variable Valve Actuator (VVA) Lash	C15 and C18 0.50 ± 0.08 mm (0.020 ± 0.003 inch)
   Cylinders	1–2–4

6. Adjust the VVA lash using the specifications from Table 10.

   1. Loosen the adjustment screw locknut. Turn the screw clockwise until contact is made with the inlet rocker arm.

   2. Turn the adjustment screw counter-clockwise two full turns or until the VVA rod is no longer contacting the inlet rocker arm.

      Note: This process will ensure that all the oil is out of the cylinder for the VVA.

   3. Install the feeler gauge between the actuator piston and the inlet rocker arm.

   4. Turn the adjustment screw clockwise while sliding the feeler gauge back and forth between the actuator piston and rocker arm. Continue turning the adjustment screw in a clockwise direction until a slight drag is felt on the feeler gauge.

   5. Leave the feeler gauge between the actuator piston and rocker arm. Tighten the adjustment locknut to 50 ± 10 N·m (37 ± 7 lb ft).

      Note: Do not allow the adjustment screw to turn while torquing the locknut.

   6. Recheck the valve lash after tightening the adjustment locknut. Remove the feeler gauge.

7. Reinstall the timing pin cover and valve covers. Refer to the Disassembly and Assembly manual.