CTS 2003-2005

Camshaft, Rocker Arms & Lifters

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Removal & Installation



2.8L & 3.6L Engines
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Intake manifold assembly
     
    Ignition coil electrical connectors
     
    Wiring harnesses and wiring conduit retainers from the camshaft cover
     
    Ignition coils
     
    Camshaft cover
     
    Camshaft position (CMP) sensors
     
    CMP actuator solenoid
     
    Crankshaft pulley
     

  4.  
  5. Rotate the crankshaft until the camshafts are in the neutral (low) position. The camshaft flats will be parallel with the camshaft cover rail.
  6.  
  7. Loosen the camshaft position actuator bolt.
  8.  
  9. Remove the front cover.
    NOTE
    Do not remove the bolt at this time.

  10.  
  11. Install the Timing Chain Retention Tool EN-46108 to retain the timing chain.
  12.  
  13. Matchmark the timing chain on the camshaft position actuators.
  14.  
  15. Remove or disconnect the following:

    CMP actuator bolt
     
    Camshaft bearing caps
     
    Camshafts
     

  16.  
  17. Remove the rocker arms.
  18.  
  19. Clean and inspect the camshaft(s) and the rocker arm(s). Repair or replace as necessary.

    Click image to see an enlarged view

    Fig. Installing camshaft retention tool EN-46108 and ensure the tips are fully engaged on the timing chain (3 and 4)-2.8L and 3.6L



    Click image to see an enlarged view

    Fig. Camshaft bearing cap torque sequence-2.8L and 3.6L

  20.  

To install:

  1. Apply a liberal amount of camshaft lubricant to the pivot pocket, roller and valve slot (3) areas of the camshaft followers.
    NOTE
    The follower must be positioned squarely on the valve tip so that the full width of the roller will completely contact the camshaft lobe. If the followers are being reused you must put them back in their original location.

  2.  
  3. Place the camshaft followers in position on the valve tip and Stationary Hydraulic Lash Adjuster (SHLA).
  4.  
  5. The rounded head end of the follower goes on the SHLA while the flat end goes on the valve tip.
  6.  
  7. Clean the camshaft journals and carriers with a clean, lint-free cloth.
  8.  
  9. Lubricate the camshaft lobes, lifters and bearing journals with camshaft lubricant.
  10.  
  11. Position the camshaft lobes in a neutral position with the flats on the back of the camshafts up and parallel with the left cylinder head camshaft cover rail.
    WARNING
    The bearing caps must be installed in their original positions.

  12.  
  13. Install the camshaft bearing thrust cap in the first journal of the cylinder head.
  14.  
  15. Install the remaining bearing caps with their orientation mark toward the center of the cylinder head.
  16.  
  17. Hand start all the camshaft bearing cap bolts.
  18.  
  19. Tighten the bearing cap bolts in sequence as follows:
    1. Step 1: Tighten all bolts to 89 inch lbs. (10 Nm).
    2.  
    3. Step 2: Loosen the center intake camshaft bearing cap bolts (1,2) and center exhaust camshaft bearing cap (3.4).
    4.  
    5. Step 3: Retighten center camshaft bearing cap bolts to 89 inch lbs. (10 Nm).
    6.  

  20.  
  21. Remove the Timing chain retention tool EN-46108.
  22.  
  23. Install or connect the following:

    CMP actuators. Tighten the bolts to 43 ft. lbs. (58 Nm).
     
    Front cover
     
    CMP actuator solenoid
     
    CMP sensors
     
    Crankshaft pulley
     
    Camshaft cover
     
    Ignition coils
     
    Wiring harnesses and conduit retainers to the camshaft cover
     
    Ignition coil electrical connectors
     
    Intake manifold
     
    Negative battery cable
     

  24.  
  25. Start the engine and verify proper operation.
  26.  

3.2L Engine
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Intake plenum
     
    Intake air resonator
     
    Camshaft cover
     
    Front timing belt cover
     
    Timing belt
     

  4.  
  5. Rotate the crankshaft 60 degrees counterclockwise Before Top Dead Center (BTDC) to prevent valve/piston contact.

    Click image to see an enlarged view

    Fig. Camshaft gear holding tools must be installed before attempting to remove the gears from the camshafts

  6.  
  7. Use a Camshaft Locking tool to hold the camshaft gears in place and loosen the camshaft gear bolt.
  8.  
  9. Remove the locking tool from the gears.
  10.  
  11. Remove the camshaft gear(s).
    NOTE
    Be certain that the camshaft is not under load from the lifters.

  12.  
  13. Gradually loosen the camshaft bearing cap bolts sequentially, starting in the center and working outward in a spiral. Note the identification marks on the caps.
  14.  
  15. Remove the valve lifters from the bores using a magnet.
  16.  
  17. Place the valve lifters in a rack sequentially so they can be reinstalled in their original order if the valve lifters are to be reused.

    Click image to see an enlarged view

    Fig. Camshaft bearing cap locations-right cylinder head

  18.  
  19. Remove the camshaft from the cylinder head.
  20.  

To install:

  1. Lubricate the valve lifters with engine prelube, GM 1052367, or equivalent.
  2.  
  3. Install the valve lifters in their original position if not replaced.
  4.  
  5. Lubricate the camshaft lobes, lifters and bearing journals with camshaft prelube.
  6.  
  7. Install the camshaft to the cylinder head.
  8.  
  9. To reduce the lifter load, position the pin on the front of the camshaft as follows:

    1 o-clock position: right exhaust camshaft
     
    11 o-clock position: right intake camshaft
     
    12 o-clock position: left exhaust camshaft
     
    7 o-clock position: left intake camshaft

    Click image to see an enlarged view

    Fig. Camshaft bearing cap locations-left cylinder head



    Click image to see an enlarged view

    Fig. Camshaft bolt torque sequence

     

  10.  
  11. Place a small amount of Loctite® on the edge of the front bearing cap to ensure a good seal between the cap and surface of the cylinder head. Do not allow the sealer to get into the oil journal of the cap.
    WARNING
    The bearing caps must be installed in their original positions.

  12.  
  13. Install or connect the following:
    NOTE
    Make certain that the camshaft seal is fully seated.


    WARNING
    A new camshaft gear bolt must be installed. The required tightening method will stretch the bolt making the original bolt unusable.



    Camshaft bearing caps. Torque the bolts in sequence and in several passes to 71 inch lbs. (8 Nm).
     
    New camshaft seal lubricated with engine oil
     



    Camshaft gear. Tighten the new bolt to 37 ft. lbs. (50 Nm), plus a 60 degree turn, plus a 15 degree turn.
     



    Timing belt and adjust as needed
     
    Front timing belt cover. Torque the bolts to 71 inch lbs. (8 Nm).
     
    Camshaft cover. Torque the bolts to 71 inch lbs. (8 Nm).
     
    Intake plenum. Torque the bolts to 71 inch lbs. (8 Nm).
     
    Intake air resonator
     
    Negative battery cable
     

  14.  
  15. Start the vehicle and verify the engine is running properly.
  16.  

5.7L Engine
  1. Before servicing the vehicle, refer to the precautions in the beginning of this engine.
  2.  
  3. Remove or disconnect the following:

    Engine assembly
     
    Intake manifold
     
    Left cylinder head
     
    Right cylinder head
     
    Camshaft position (CMP) sensor
     
    Front cover
     
    Valve lifter guide bolts
     
    Valve lifters and guides
     

  4.  
  5. Rotate the crankshaft in order to align the timing marks.
  6.  
  7. Remove the camshaft sprocket bolts.
  8.  
  9. Remove the timing chain from the camshaft sprocket, and allow the chain to rest on the crankshaft sprocket.
  10.  
  11. Remove the camshaft retainer bolts and retainer.
  12.  
  13. Install 3 M8 - 4 inch (100 mm) in the camshaft front bolt holes.
  14.  
  15. Using the bolts as a handle, rotate and pull the camshaft out of the engine block.

    Click image to see an enlarged view

    Fig. Removing the camshaft using the bolts as a handle-5.7L

  16.  

To install:

  1. Lubricate the camshaft journals and the bearings with clean engine oil.
  2.  
  3. Install 3 M8 - 4 inch (100 mm) in the camshaft front bolt holes.
  4.  
  5. Using the bolts as a handle, carefully install the camshaft into the engine block.
  6.  
  7. Remove the 3 bolts from the front of the camshaft.
  8.  
  9. Install the camshaft retainer. Tighten the bolts as follows:
    1. Hex head bolts to 18 ft. lbs (25 Nm)
    2.  
    3. TORX® head bolts to 11 ft. lbs. (15 Nm)
    4.  

  10.  
  11. CMP sensor. Tighten the bolt to 18 ft. lbs (25 Nm).
    NOTE
    Lubricate the sensor O-ring seal with clean engine oil.

  12.  
  13. Install or connect the following:

    Timing chain to the camshaft sprocket
     
    Camshaft sprocket and bolts to the camshaft. Tighten the bolts to 26 ft. lbs. (35 Nm).
     
    Valve lifters, valve guides and guide bolts
     
    Front cover
     
    CMP sensor
     
    Right cylinder head
     
    Left cylinder head
     
    Intake manifold
     
    Engine assembly
     

  14.  
  15. Start the engine and check for leaks.
  16.  

 
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