Escalade, Suburban, Tahoe, Yukon, Denali, DenaliXL, YukonXL 1999-2005

Camshaft, Bearings & Lifters 1

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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. Drive the camshaft rear plug from the block.
  2.  
  3. Assemble the removal puller with its shoulder on the bearing to be removed. Gradually tighten the puller nut until the bearing is removed.
  4.  
  5. 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 towards 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 the diesel. 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

  6.  
  7. 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.

  8.  
  9. Replace the camshaft rear plug, and stake it into position. On the Diesel, 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.
  10.  

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 towards 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. 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 the Diesel, 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




CAUTION
Wear safety glasses in order to avoid eye damage.

  1. Clean the engine camshaft in cleaning solvent.
  2.  
  3. Dry the engine camshaft with compressed air.
  4.  
  5. Inspect the camshaft retainer plate for damage. If the camshaft retainer plate is damaged, replace as necessary.
  6.  
  7. Inspect the camshaft bearings for correct fit into the engine block camshaft bearing bores. The camshaft bearings have an interference fit to the engine block camshaft bearing bores and must not be loose in the engine block camshaft bearing bores.
    NOTE
    If any camshaft bearing is excessively worn or scored, replace all the camshaft bearings. Inspect the camshaft bearings for excessive wear or scoring.



    Click image to see an enlarged view

    Fig. Camshaft-typical. See text for component identification

  8.  
  9. Inspect the engine camshaft for the following:

    Worn, scored, or damaged bearing journals (1)
     
    Worn engine camshaft lobes (2)
     
    Damaged bolt hole threads (3)
     
    Damaged camshaft sprocket locator pin (4)
     

  10.  
  11. Measure the engine camshaft journals with a micrometer. If the camshaft journals are more than 0.025 mm (0.0010 in) out-of-round, then replace the engine camshaft.

    Click image to see an enlarged view

    Fig. Using a micrometer to measure camshaft journal

  12.  
  13. Measure for a bent engine camshaft or excessive engine camshaft runout using tool J7872 or equivalent.

    Mount the engine camshaft in a suitable stand between centers.
     
    Use tool J7872 or equivalent in order to check the intermediate engine camshaft journals. If the runout exceeds 0.065 mm (0.0026 in), the engine camshaft is bent and must be replaced.

    Click image to see an enlarged view

    Fig. Using tool J7872 to measure runout and camshaft lobe lift

     

  14.  
  15. Measure the engine camshaft lobe lift using tool J7872 or equivalent.

    Place the engine camshaft on the V-blocks.
     
    Use tool J7872 or equivalent in order to measure the engine camshaft lobe lift.
     

  16.  
  17. Replace the engine camshaft if the engine camshaft lobe lift is not within specifications.
  18.  

Camshaft
End Play

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.

Click image to see an enlarged view

Fig. Checking camshaft end-play

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

End-Play Specifications


4.3L engine: 0.0010-0.0090 in (0.0254-0.2286 mm)
 
4.8L, 5.3L engines: 0.001-0.012 in. (0.025-0.305mm)
 
5.0 and 5.7L engines: 0.002-0.012 in, (0.05-0.30mm)
 
6.0L engines: 0.001-0.012 in. (0.025-0.305mm)
 
6.5L engines: 0.002-0.012 in, (0.51-0.305mm)
 
6.6L engines: 0.002-0.0045 in. (0.050-0.114mm) and service limit is 0.008 in. (0.20mm)
 
7.4L engines: not available at the time of publication
 
8.1L engines: not available at the time of publication
 

Lobe Height

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.

Click image to see an enlarged view

Fig. Checking camshaft lobe height



Click image to see an enlarged view

Fig. Checking camshaft journal diameter

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

Lobe Height Specifications


4.3L engine: intake: 0.2704 in. (6.8678mm), exhaust: 0.2793 in. (7.0953mm)
 
4.8L, 5.3L engines: intake: 0.268 in. (6.82mm), exhaust 0.274 in. (6.96mm)
 
5.0 and 5.7L engines: intake: 0.274-0.278 in. (6.97-7.07mm), exhaust 0.283-0.287 in. (7.20-7.30mm)
 
6.0L engines: intake: 0.274 in. (6.96mm), exhaust: 0.281 in. (7.13mm)
 
6.5L engines: 0.2790-0.2830 in. (7.0830-7.1830mm)
 
6.6L engines: intake: 0.2863 in. (7.273mm), exhaust: 0.2326 in. (5.907mm)
 
7.4L engines: intake: 0.2801-0.2841 in. (7.115-7.216.mm), exhaust: 0.2823-0.2863 in. (7.170-7.272mm)
 
8.1L engines: intake: 0.2726-0.2766 in. (6.924-7.026mm), exhaust: 0.2745-0.2785in. (6.973-7.075mm)
 


NOTE
If only one lobe height specification is given then both intake and exhaust lobes have the same specification.

Runout

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.

Click image to see an enlarged view

Fig. Checking camshaft run-out

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

Run-Out Specifications


4.3L engine: 0.0039 in. (0.100mm)
 
4.8L, 5.3L engines: 0.002 in. (0.05mm)
 
5.0 and 5.7L engines: 0.0026 in. (0.065mm)
 
5.3L engines: 0.002 in. (0.05mm)
 
6.0L engines: 0.002 in. (0.05mm)
 
6.5L engines: not available at the time of publication
 
6.6L engines: 0.002 in. (0.05mm)
 
7.4L engines: 0.002 in. (0.051mm)
 
8.1L engines:0.003 in. (0.076mm)
 

 
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