Silverado 2008

Camshaft And Valve Lifters

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Camshaft Bearing Replacement



If excessive camshaft wear is found, or if the engine is completely rebuilt, the camshaft bearings should be replaced.


NOTE
The front and rear bearings should be removed last, and installed first. Those bearings act as guides for the other bearings and pilot.

  1. Remove the engine.
  2.  
  3. Drive the camshaft rear plug from the block.
  4.  
  5. Assemble the removal puller with its shoulder on the bearing to be removed. Gradually tighten the puller nut until the bearing is removed.
  6.  
  7. Remove the remaining bearings, leaving the front and rear for last. To remove these, reverse the position of the puller, so as to pull the bearings toward the center of the block. Leave the tool in this position, pilot the new front and rear bearings on the installer, and pull them into position.

    Click image to see an enlarged view

    Fig. Removing the camshaft bearings



    Click image to see an enlarged view

    Fig. Replacing the inner camshaft bearing



    Click image to see an enlarged view

    Fig. Installing the outer camshaft bearing



    Click image to see an enlarged view

    Fig. Installing the front camshaft bearing on diesel engines. The bearing tool is shown in the inset



    Click image to see an enlarged view

    Fig. Make this simple tool to check camshaft bearing oil hole alignment

  8.  
  9. Return the puller to its original position and pull the remaining bearings into position.
    NOTE
    You must make sure that the oil holes of the bearings and block align when installing the bearings. If they don't align, the camshaft will not get proper lubrication and may seize or at least be seriously damaged. To check for correct oil hole alignment, use a piece of brass rod with a 90° bend in the end as shown in the illustration. Check all oil hole openings. The wire must enter each hole, or the hole is not properly aligned.

  10.  
  11. Replace the camshaft rear plug, and stake it into position. On diesel engines, coat the outer diameter of the new plug with GM sealant #1052080 or equivalent, and install it flush to 1 / 32 in. (0.794mm) deep.
  12.  

Inspection



End-Play

Specific to:

Chevrolet Silverado 1500 2008

After the camshaft has been installed, end-play should be checked. The camshaft sprocket should be installed on the cam. Use a dial gauge to check the end-play, by moving the camshaft forward and backward. Refer to the Camshaft Specifications chart.

Click image to see an enlarged view

Fig. Checking camshaft end-play

Run-Out

Specific to:

Chevrolet Silverado 1500 2008

Camshaft run-out should be checked when the camshaft has been removed from the engine. An accurate dial indicator is needed for this procedure. If the run-out exceeds the limit replace the camshaft. Refer to the Camshaft Specifications chart.

Click image to see an enlarged view

Fig. Checking camshaft run-out

Lobe Height

Specific to:

Chevrolet Silverado 1500 2008

Use a micrometer to check camshaft (lobe) height, making sure the anvil and the spindle of the micrometer are positioned directly on the heel and tip of the camshaft lobe as shown in the accompanying illustration. Refer to the Camshaft Specifications chart.

Click image to see an enlarged view

Fig. Checking camshaft lobe height



Click image to see an enlarged view

Fig. Checking camshaft journal diameter

Removal & Installation



4.3L Engine

Specific to:

Chevrolet Silverado 1500 2008

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Properly relieve the fuel system pressure.
  4.  
  5. Drain the engine cooling system.
  6.  
  7. Remove or disconnect the following:

    Negative battery cable
     
    Radiator
     
    Cooling fan
     
    Water pump
     
    Rocker arm covers
     
    Intake manifold assembly
     
    Rocker arms, pushrods and lifters
     
    Crankshaft pulley and hub
     
    Engine front cover
     

  8.  
  9. Align the timing marks on the crankshaft and camshaft sprockets.
    NOTE
    Install the sprocket bolts or longer bolts of the same thread into the end of the camshaft as a handle.



    Camshaft sprocket and timing chain
     
    Balance shaft drive gear, if equipped
     
    Camshaft thrust plate
     



    Camshaft

    Click image to see an enlarged view

    Fig. Camshaft removal-4.3L engines



    Click image to see an enlarged view

    Fig. Camshaft and related components-4.3L engines

     

  10.  

To install:

  1. Lubricate the camshaft journals with clean engine oil or a suitable pre-lube.
  2.  
  3. Install or connect the following:

    Camshaft
     
    Camshaft thrust plate
     
    Balance shaft drive gear, if equipped
     
    Timing chain and camshaft sprocket
     
    Engine front cover
     
    Crankshaft pulley and hub
     
    Valve lifters
     
    Pushrods and rocker arms, properly adjust the valve clearance
     
    Intake manifold assembly
     
    Rocker arm covers to the engine
     
    Radiator to the vehicle
     
    Negative battery cable
     

  4.  
  5. Refill the engine cooling system.
  6.  

4.8L, 5.3L & 6.0L Engines

Specific to:

Chevrolet Silverado 1500 2008

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Properly relieve the fuel system pressure.
  6.  
  7. Properly discharge the air conditioning system.
  8.  
  9. Remove the radiator support.
  10.  
  11. Remove the engine front cover.
  12.  
  13. Remove the valve lifters.
  14.  
  15. Remove the camshaft sensor bolt and sensor.

    Click image to see an enlarged view

    Fig. Camshaft sensor removal-4.8L, 5.3L & 6.0L engines

  16.  
  17. Rotate the crankshaft until the timing marks are aligned. Remove the camshaft sprocket bolt.
  18.  
  19. Remove the bolts and the timing chain tensioner. Remove the camshaft sprocket and reposition the timing chain.
  20.  
  21. Remove the camshaft retainer bolts and retainer.

    Click image to see an enlarged view

    Fig. Camshaft retainer removal-4.8L, 5.3L & 6.0L engines



    Click image to see an enlarged view

    Fig. Camshaft removal-4.8L, 5.3L & 6.0L engines

  22.  
  23. Install a bolt into the camshaft. Using the bolt as a handle carefully remove the camshaft from the engine.

    Click image to see an enlarged view

    Fig. Camshaft and related components-4.8L and 5.3L engines



    Click image to see an enlarged view

    Fig. Camshaft and related components-6.0L engines

  24.  

To install:


NOTE
Be sure to use new fasteners, as required.


NOTE
If camshaft replacement is required, the valve lifters must also be replaced.

  1. Clean and inspect all sealing surfaces.
  2.  
  3. Lubricate the camshaft journals and the bearings with clean engine oil.
    NOTE
    All camshaft journals are the same diameter, so care must be used in removing or installing the camshaft to avoid damage to the camshaft bearings.

  4.  
  5. Using a bolt as a handle, carefully install the camshaft into the engine block. Remove the bolt from the front of the camshaft.
  6.  
  7. Install the retainer plate. Tighten the retainer bolts to 18 ft. lbs. (25 Nm) for first design hex head bolts and 11 ft. lbs. (15 Nm) for second design Torx® head bolts.

    Click image to see an enlarged view

    Fig. Camshaft retainer plate identification-4.8L, 5.3L & 6.0L engines

  8.  
  9. Continue the installation in the reverse order of the removal procedure.
  10.  
  11. Start the engine and check for leaks.
  12.  
  13. Correct as required.
  14.  

 
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