C6.6 Engines for Caterpillar Built Machines Inlet and Exhaust Valve Springs - Remove and Install Caterpillar

Removal Procedure

Start By:

1. Remove the rocker shaft assembly. Refer to Disassembly and Assembly, "Rocker Shaft and Pushrod - Remove" for the correct procedure.

Note: Either Tooling (C) can be used. Use the Tooling that is most suitable.

Note: The following procedure should be adopted to remove the valve springs when the cylinder head is installed to the engine. Refer to Disassembly and Assembly, "Inlet and Exhaust Valves - Remove and Install" for the procedure to remove the valve springs from a cylinder head that has been removed from the engine.

Note: Ensure that the appropriate piston is at top dead center before the valve spring is removed. Failure to ensure that the piston is at top dead center may allow the valve to drop into the cylinder bore.

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Personal injury can result from being struck by parts propelled by a released spring force. Make sure to wear all necessary protective equipment. Follow the recommended procedure and use all recommended tooling to release the spring force.

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Illustration 1	g01335929

1. Follow Steps 1.a through 1.h to remove the harness assemblies for the electronic unit injectors.

   1. Place a temporary identification mark on connections (1) for harness assembly (4) for electronic unit injectors (2).

   2. Use a deep socket to remove connections (1) from electronic unit injectors (2).

   3. Cut the cable straps (3).

   4. Disconnect plug (7) from harness assembly (4).

   5. Use Tooling (A) to remove circlip (5).

   6. From the outside of valve mechanism cover base (8), push harness assembly (4) inward. Withdraw the harness assembly from the valve mechanism cover base.

   7. Remove O-ring seal (6) from harness assembly (4).

   8. Repeat Steps 1.a through 1.g to remove the remaining harness assemblies.
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   Illustration 2	g01335931

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   NOTICE
   Ensure that the valve spring is compressed squarely or damage to the valve stem may occur.

2. Follow Steps 2.a through 2.d to position the appropriate piston at top dead center.

   1. Install Tooling (B) in position on the cylinder head to compress a valve spring (11) for the appropriate piston.

   2. Use Tooling (B) to compress valve spring (11) and open the valve slightly.

      Note: Do not compress the spring so that the valve spring retainer (10) touches the valve stem seal.

   3. Use Tooling (C) to rotate the crankshaft carefully, until the piston touches the valve.

      Note: Not use excessive force to turn the crankshaft. The use of force can result in bent valve stems.

   4. Continue to rotate the crankshaft and gradually release the pressure on Tooling (B) until the piston is at the top dead center position. The valve is now held in a position that allows the valve spring to be safely removed.

   Note: Valve springs must be replaced in pairs for the inlet valve or the exhaust valve of each cylinder. If all valve springs require replacement the procedure can be carried out on two cylinders at the same time. The procedure can be carried out on the following pairs of cylinders. 1 with 6, 2 with 5 and 3 with 4. Ensure that all the valve springs are installed before changing from one pair of cylinders to another pair of cylinders.

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   NOTICE
   Do not turn the crankshaft while the valve springs are removed.

3. Apply sufficient pressure to Tooling (B) to allow removal of valve keepers (8).

   Note: Do not compress the spring so that valve spring retainer (9) touches the valve stem seal.

   Remove valve keepers (9).

4. Slowly release pressure on Tooling (B).

5. Remove valve spring retainer (10) and remove valve spring (11).

6. If necessary, remove the valve stem seals.

7. Repeat Steps 3 through 6 to remove the remaining valve springs from the appropriate cylinder.

8. Remove Tooling (B).

Installation Procedure

Note: Either Tooling (C) can be used. Use the Tooling that is most suitable.

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NOTICE
Plug the apertures for the push rods in the cylinder head to prevent the entry of loose parts into the engine.

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Illustration 3	g01335931

1. Inspect valve springs (11) for damage and for the correct length. Refer to Specifications, "Cylinder Head Valves" for the correct procedure.

2. If necessary, install a new valve stem seal onto the valve guide.

   Note: The outer face of the valve guide must be clean and dry before installing the valve stem seal.

3. Install valve spring (11) onto the cylinder head. Position valve spring retainer (10) on valve spring (11).
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   Improper assembly of parts that are spring loaded can cause bodily injury. To prevent possible injury, follow the established assembly procedure and wear protective equipment.

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   NOTICE
   Ensure that the valve spring is compressed squarely or damage to the valve stem may occur.

4. Install Tooling (B) in the appropriate position on the cylinder head to compress valve spring (11).

5. Apply sufficient pressure to Tooling (B) to install valve keepers (9).

   Note: Do not compress the spring so that valve spring retainer (10) touches the valve stem seal.

   Install the valve spring keepers.

6. Carefully release the pressure on Tooling (B).

7. Repeat steps 2 to 6 for the remaining valves.
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   The valve spring keepers can be thrown from the valve when the valve spring compressor is released. Ensure that the valve spring keepers are properly installed on the valve stem. To help prevent personal injury, keep away from the front of the valve spring keepers and valve springs during the installation of the valves.

8. Remove Tooling (B).

9. Use Tooling (C) to rotate the crankshaft through approximately 45 degrees. Rotate the crankshaft through approximately 45 degrees will ensure that the appropriate valve is clear of the piston. Lightly strike the top of the valve with a soft hammer to ensure that valve keepers (9) are properly installed.

   Note: If all valve springs require replacement the procedure can be carried out on two cylinders at the same time. The procedure can be carried out on the following cylinders. 1 and 6, 2 and 5 and 3 and 4. Remember that the crankshaft must not be turned while the valve springs are removed. Ensure that all the valve springs are installed before changing from one pair of cylinders to the other pair of cylinders. If all valve springs do not require replacement, the springs must be replaced in pairs.

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   Illustration 4	g01335929

10. Follow Steps 10.a through 10.g to install the harness assemblies for the electronic unit injectors.

    1. Ensure that harness assembly (4) for the electronic unit injectors and the bore in valve mechanism cover base (8) are clean and free from damage. Replace any damaged components.

    2. Use Tooling (D) to lubricate a new O-ring seal. Install new O-ring seal (6) onto harness assembly (4) for the electronic unit injectors.

    3. Install harness assembly (4) into valve mechanism cover base (8) from inside the valve mechanism cover base.

    4. Use Tooling (A) to install circlip (5).

    5. Connect plug (7) to harness assembly (4) for the electronic unit injectors.

    6. Use a deep socket to install connections (1) to electronic unit injectors (2). Use Tooling (E) to tighten the connections to a torque of 2.4 N·m (21 lb in).

    7. Install a new cable strap (3).

       Note: Ensure that cable straps meet Original Equipment Manufacturer (OEM) specification are used.

    8. Repeat Steps 10.a through 10.g for the remaining harness assemblies.

End By:

1. Install the rocker shaft assembly. Refer to Disassembly and Assembly, "Rocker Shaft and Pushrod - Install" for the correct procedure.