Express, Savana, G1500, G2500, G3500, 1998-2005

Camshaft, Bearings & Lifters

Print

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 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



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)
 
7.4L engines: specification not available at the time of publication
 
8.1L engines: specification 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)
 
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
 
7.4L engines: 0.002 in. (0.051mm)
 
8.1L engines:0.003 in. (0.076mm)
 

Removal & Installation



4.3L Engine
  1. Properly relieve the fuel system pressure.
  2.  
  3. Drain the engine cooling system.
  4.  
  5. Remove or disconnect the following:

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

  6.  
  7. 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
     

  8.  

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.  

  1. Properly relieve the fuel system pressure.
  2.  
  3. Drain the engine cooling system.
  4.  
  5. Remove or disconnect the following:

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

  6.  
  7. 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
     

  8.  

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
  1. Raise the hood to the servicing position and secure it. Move the hood hinge bolt to hold the hood in the servicing position.
  2.  
  3. Remove or disconnect the following:

    Battery negative cable
     
    Coolant
     
    Upper and lower radiator hoses from the engine
     
    Air cleaner duct from the engine
     
    A/C condenser mounting bolts, if equipped
     
    Radiator support and radiator
     
    Engine cooling fan
     
    Drive belt
     
    A/C drive belt, if equipped
     
    Engine sight shield
     
    Electrical wiring harness from the thermostat housing
     
    Water pump

    Click image to see an enlarged view

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

     

  4.  
  5. Raise the vehicle.

    Click image to see an enlarged view

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



    Starter motor
     
    Right side closeout cover and bolt
     
    Crankshaft balancer
     
    Engine oil pan
     
    Engine front cover
     
    Cylinder heads from the engine
     
    Valve lifters from the engine
     

  6.  
  7. Align the timing marks on the camshaft and crankshaft sprockets. Make sure that the number 1 piston is in the firing position.
    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.



    Camshaft sprocket
     
    Camshaft sensor bolt and sensor
     
    Camshaft retainer bolts and retainer
     

  8.  
  9. Install the three M8-1.25 x 100 mm bolts in the camshaft front bolt holes. Using the bolts as a handle, carefully rotate and pull the camshaft out of the engine block. Remove the bolts from the front of the camshaft.
  10.  
  11. Clean and inspect all sealing surfaces.
  12.  

To install:


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

  1. Lubricate the camshaft journals and the bearings with clean engine oil. Install three M8-1.25 x 100 mm (M8-1.25 x 4.0 inch) bolts into the camshaft front bolt holes.
    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.

  2.  
  3. Using the bolts as a handle, carefully install the camshaft into the engine block. Remove the three bolts from the front of the camshaft.
    NOTE
    Install the retainer plate with the sealing gasket facing the engine block. The gasket surface on the engine block should be clean and free of dirt or debris.

  4.  
  5. Install or connect the following:

    Camshaft retainer and the bolts. Tighten the camshaft retainer bolts to 18 ft. lbs. (25 Nm).
     

  6.  
  7. Inspect the camshaft sensor O-ring seal. If the O-ring seal is not cut or damaged, it may be reused. Lubricate the O-ring seal with clean engine oil.

    Camshaft sensor and bolt. Tighten the bolt to 18 ft. lbs. (25 Nm).
     
    Camshaft sprocket and timing chain
     
    Valve lifters
     
    Cylinder heads
     
    Engine front cover to the engine
     
    Oil pan
     
    Right side closeout cover
     
    Starter motor
     
    Crankshaft balancer to the crankshaft
     
    Water pump
     
    Electrical wiring harness to the thermostat housing
     
    A/C drive belt, if equipped
     
    Drive belt
     
    Engine sight shield
     
    Radiator support and radiator
     
    A/C condenser mounting bolts
     
    Engine cooling fan
     
    Air cleaner duct
     
    Negative battery cable
     

  8.  

  1. Raise the hood to the servicing position and secure it. Move the hood hinge bolt to hold the hood in the servicing position.
  2.  
  3. Remove or disconnect the following:

    Battery negative cable
     
    Coolant
     
    Upper and lower radiator hoses from the engine
     
    Air cleaner duct from the engine
     
    A/C condenser mounting bolts, if equipped
     
    Radiator support and radiator
     
    Engine cooling fan
     
    Drive belt
     
    A/C drive belt, if equipped
     
    Engine sight shield
     
    Electrical wiring harness from the thermostat housing
     
    Water pump

    Click image to see an enlarged view

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

     

  4.  
  5. Raise the vehicle.

    Starter motor
     
    Right side closeout cover and bolt
     
    Crankshaft balancer
     
    Engine oil pan
     
    Engine front cover
     
    Cylinder heads from the engine
     
    Valve lifters from the engine

    Click image to see an enlarged view

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

     

  6.  
  7. Align the timing marks on the camshaft and crankshaft sprockets. Make sure that the number 1 piston is in the firing position.
    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.



    Camshaft sprocket
     
    Camshaft sensor bolt and sensor
     
    Camshaft retainer bolts and retainer
     

  8.  
  9. Install the three M8-1.25 x 100 mm bolts in the camshaft front bolt holes. Using the bolts as a handle, carefully rotate and pull the camshaft out of the engine block. Remove the bolts from the front of the camshaft.
  10.  
  11. Clean and inspect all sealing surfaces.
  12.  

To install:


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

  1. Lubricate the camshaft journals and the bearings with clean engine oil. Install three M8-1.25 x 100 mm (M8-1.25 x 4.0 in) bolts into the camshaft front bolt holes.
    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.

  2.  
  3. Using the bolts as a handle, carefully install the camshaft into the engine block. Remove the three bolts from the front of the camshaft.
    NOTE
    Install the retainer plate with the sealing gasket facing the engine block. The gasket surface on the engine block should be clean and free of dirt or debris.

  4.  
  5. Install or connect the following:

    Camshaft retainer and the bolts. Tighten the camshaft retainer bolts to 18 ft. lbs. (25 Nm).
     

  6.  
  7. Inspect the camshaft sensor O-ring seal. If the O-ring seal is not cut or damaged, it may be reused. Lubricate the O-ring seal with clean engine oil.

    Camshaft sensor and bolt. Tighten the bolt to 18 ft. lbs. (25 Nm).
     
    Camshaft sprocket and timing chain
     
    Valve lifters
     
    Cylinder heads
     
    Engine front cover to the engine
     
    Oil pan
     
    Right side closeout cover
     
    Starter motor
     
    Crankshaft balancer to the crankshaft
     
    Water pump
     
    Electrical wiring harness to the thermostat housing
     
    A/C drive belt, if equipped
     
    Drive belt
     
    Engine sight shield
     
    Radiator support and radiator
     
    A/C condenser mounting bolts
     
    Engine cooling fan
     
    Air cleaner duct
     
    Negative battery cable
     

  8.  

5.0L & 5.7L Engines
  1. Drain the cooling system.
  2.  
  3. Properly relieve the fuel system pressure.
  4.  
  5. Remove or disconnect the following:

    Engine cover, if equipped
     
    Air cleaner
     
    Grille and center support, if equipped
     
    Air conditioning condenser and swing the condenser forward from its mounting, if equipped.
     
    Fan, the shroud and the radiator
     
    Valve covers
     
    Water pump assembly
     

  6.  
  7. Align the timing marks and remove the torsional damper.

    Timing chain cover
     
    Electrical and vacuum connections at the intake manifold
     
    Distributor assembly, mark the distributor rotor-to-housing location
     
    Intake manifold, pushrods and hydraulic lifters
     
    Camshaft sprocket bolts
     
    Camshaft sprocket and timing chain
     
    Crankshaft sprocket, as required
     
    Front engine mount through-bolts and raise the engine to gain sufficient clearance for camshaft removal, as required
     

  8.  
  9. Install 2 or 3 5 / 16 -18 bolts 4-5 in. (102-127mm) long into the camshaft threaded holes.
    NOTE
    Inspect the shaft for signs of excessive wear or damage.



    Camshaft
     

  10.  

To install:


NOTE
Liberally coat camshaft and bearing with heavy engine oil or engine assembly lubricant.

  1. Install or connect the following:

    Camshaft, align the timing marks on the camshaft and crankshaft gears
     
    Engine mount through-bolts
     
    Camshaft sprocket and chain. Torque the bolts to 18 ft. lbs. (25 Nm).
     
    Hydraulic lifters and pushrods
     
    Distributor assembly
     
    Timing chain cover
     
    Torsional damper
     
    Water pump
     
    Valve covers
     
    Fan, the shroud and radiator
     
    Air conditioning condenser, if equipped
     
    Grille and center support, if equipped
     
    Air cleaner
     
    Engine cover, if equipped
     
    Negative battery cable
     

  2.  
  3. Refill the cooling system.
  4.  

6.5L Engine
  1. Drain the cooling system.
  2.  
  3. Relieve the fuel system pressure.
  4.  
  5. Remove or disconnect the following:

    Battery cables
     
    Headlight bezels
     
    Grille, bumper and lower valance panel
     
    Hood latch
     
    Coolant recovery bottle
     
    Upper tie bar
     
    Air conditioner compressor
     
    Radiator and fan
     
    Oil pump drive
     
    Cylinder heads to gain clearance for lifter removal
     
    Alternator lower bracket
     
    Water pump
     
    Torsional damper
     
    Front cover
     
    Injection pump
     
    Rocker arm covers
     
    Rocker arm assemblies and pushrods. Mark them so they can be returned to their original position.
     
    Hydraulic lifters and keep them in order so they can be returned to their original bore.
     
    Timing chain and camshaft sprocket
     
    Thrust plate bolts and thrust plate
     
    Camshaft from the block
     
    Thrust plate spacer, if necessary
     

  6.  

To install:

  1. Install the spacer with the I.D. chamfer toward the camshaft.
    NOTE
    It is recommended that the engine oil, oil filter and hydraulic lifters be replaced when installing a new camshaft.

  2.  
  3. Coat the camshaft lobes with Molykote®, or equivalent.
  4.  
  5. Lubricate the camshaft journals with engine oil.
  6.  
  7. Install or connect the following:

    Camshaft carefully into the block
     
    Thrust plate and bolts. Torque the bolts to 17 ft. lbs. (23 Nm).
     
    Timing chain and sprockets, align the timing marks
     
    Hydraulic lifters in the same bore as they were removed
     
    Rocker arm assemblies and pushrods in their original locations
     
    Rocker arm covers
     
    Fuel pump
     
    Front cover
     
    Torsional damper and water pump
     
    Alternator lower bracket
     
    Cylinder heads
     
    Oil pump drive
     
    Radiator and fan
     
    Air conditioner compressor
     
    Upper tie bar
     
    Coolant recovery bottle
     
    Hood latch
     
    Grille, bumper and lower valence panel
     
    Headlight bezels
     
    Battery cables
     

  8.  
  9. Refill the cooling system.
  10.  
  11. Evacuate and charge the air conditioner system.
  12.  

  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Drain the cooling system.
  4.  
  5. Relieve the fuel system pressure.
  6.  
  7. Remove or disconnect the following:

    Battery cables
     
    Headlight bezels
     
    Grille, bumper and lower valance panel
     
    Hood latch
     
    Coolant recovery bottle
     
    Upper tie bar
     
    Air conditioner compressor
     
    Radiator and fan
     
    Oil pump drive
     
    Cylinder heads to gain clearance for lifter removal
     
    Alternator lower bracket
     
    Water pump
     
    Torsional damper
     
    Front cover
     
    Injection pump
     
    Rocker arm covers
     
    Rocker arm assemblies and pushrods. Mark them so they can be returned to their original position.
     
    Hydraulic lifters and keep them in order so they can be returned to their original bore.
     
    Timing chain and camshaft sprocket
     
    Thrust plate bolts and thrust plate
     
    Camshaft from the block
     
    Thrust plate spacer, if necessary
     

  8.  

To install:

  1. Install the spacer with the ID chamfer toward the camshaft.
    NOTE
    It is recommended that the engine oil, oil filter and hydraulic lifters be replaced when installing a new camshaft.

  2.  
  3. Coat the camshaft lobes with Molykote®, or equivalent.
  4.  
  5. Lubricate the camshaft journals with engine oil.
  6.  
  7. Install or connect the following:

    Camshaft carefully into the block
     
    Thrust plate and bolts. Torque the bolts to 17 ft. lbs. (23 Nm)
     
    Timing chain and sprockets, align the timing marks
     
    Hydraulic lifters in the same bore as they were removed
     
    Rocker arm assemblies and pushrods in their original locations
     
    Rocker arm covers
     
    Fuel pump
     
    Front cover
     
    Torsional damper and water pump
     
    Alternator lower bracket
     
    Cylinder heads
     
    Oil pump drive
     
    Radiator and fan
     
    Air conditioner compressor
     
    Upper tie bar
     
    Coolant recovery bottle
     
    Hood latch
     
    Grille, bumper and lower valence panel
     
    Headlight bezels
     
    Battery cables
     

  8.  
  9. Refill the cooling system.
  10.  
  11. Evacuate and charge the air conditioner system.
  12.  

6.6L Engine

NOTE
This procedure requires the use of the following special tools: Flywheel Holding Tool No. J 44643, Magnetic Base J 26900-13 and Dial Indicator J 26900-12.

  1. Properly discharge the A/C system.
  2.  
  3. Remove or disconnect the following:

    Both cylinder heads
     
    Valve lifter guide hold-down bracket bolts
     
    Valve lifter guide hold-down brackets
     
    Valve lifter guides
     
    Valve lifters
     
    Charged air cooler
     
    A/C condenser
     
    Starter
     

  4.  
  5. Install the Flywheel Holding Tool No. J 44643 in the starter opening. Make sure the tool is flush to the flywheel opening. The holding tool will be used to remove the crankshaft balancer bolt and camshaft drive gear bolt.
    NOTE
    The crankshaft reluctor and oil pump drive gear are timed together at the factory. Do NOT remove the reluctor from the oil pump drive gear.



    Click image to see an enlarged view

    Fig. Proper installation of the flywheel holding tool in the starter opening-6.6L engines



    Engine front cover
     
    Oil pump driven gear nut and gear
     



    Oil pump drive gear and crankshaft reluctor assembly. Do not remove the reluctor bolts or damage the reluctor teeth
     

  6.  
  7. Using the Magnetic Base J 26900-13 and Dial Indicator J 26900-12, measure the camshaft end-play. The production value is 0.002-0.0045 in. (0.050-0.114mm) and the service limit is 0.008 in. (0.20mm). Replace the cam gear or thrust plate if the measured value exceeds the service limit.
    NOTE
    Use the flywheel holding tool to hold the engine from turning while loosening the camshaft gear bolt.



    Click image to see an enlarged view

    Fig. Use the dial indicator (1) and magnetic base (2) to measure the camshaft end-play-6.6L engines



    Camshaft reluctor screws and reluctor
     



    Loosen the camshaft gear bolt and leave the bolt finger-tight
     
    Camshaft thrust plate bolts through the holes in the camshaft gear
     
    Camshaft with the gear attached
     
    Cam gear bolt and gear
     
    Thrust plate
     

  8.  
  9. Clean and inspect the camshaft and bearings.
  10.  

To install:

  1. Install or connect the following:

    Camshaft thrust plate
     
    Camshaft driven gear
     
    New driven gear bolt (finger-tight)
     
    Camshaft and gear assembly into the cylinder block. Align the gear to the crankshaft gear

    Click image to see an enlarged view

    Fig. Camshaft and crankshaft gear alignment-6.6L engines

     



    Threadlock to the thrust plate bolts
     
    Thrust plate bolts and tighten to 19 ft. lbs. (26 Nm)
     
    Camshaft reluctor to the cam gear
     
    Reluctor bolts. Tighten to 80 inch lbs. (9 Nm) in a crisscross pattern.
     
    If removed, reinstall the flywheel holding tool in the starter opening
     
    Camshaft gear bolt and tighten to 173 ft. lbs. (234 Nm)
     

  2.  
  3. Using the Magnetic Base J 26900-13 and Dial Indicator J 26900-12, measure the camshaft end-play. Replace the cam gear or thrust plate if the measured value exceeds the service limit; refer to the Camshaft Specifications chart.

    Oil pump drive gear and reluctor to the crankshaft. Do not damage the teeth of the reluctor.
     
    Oil pump driven gear and nut. Tighten to 74 ft. lbs. (100 Nm).
     
    Engine front cover
     
    A/C condenser
     
    Charged air cooler
     

  4.  
  5. Apply clean engine oil to the roller and outside of the lifters.

    Valve lifters
     
    Valve lifter guides
     
    Valve lifter guide hold-down brackets. Make sure that both tabs of the bracket are in the holes of the valve lifter guides.
     
    Valve lifter guide hold-down bracket bolts. Tighten to 97 inch lbs. (11 Nm).
     

  6.  

7.4L Engines
  1. Drain the cooling system.
  2.  
  3. Properly relieve the fuel system pressure.
  4.  
  5. Properly discharge the air conditioning system.
  6.  
  7. Remove or disconnect the following:

    Negative battery cable
     
    Engine cover, if equipped
     
    Air cleaner assembly
     
    Grille and center support section, as required
     
    Air conditioning compressor, condenser and auxiliary fan, if equipped
     
    Fan, the shroud
     
    Radiator
     
    Accessory belt, as required
     
    Alternator, as required
     
    Valve covers
     
    Hoses from the water pump
     
    Water pump
     

  8.  
  9. Align the timing marks at Top Dead Center (TDC).

    Harmonic balancer and pulley
     
    Engine front cover
     

  10.  
  11. Mark the distributor rotor-to-housing location.

    Distributor assembly
     
    Intake manifold assembly
     
    Lifters, pushrods, and rocker arms
     

  12.  
  13. Rotate the camshaft so the timing marks align.

    Camshaft sprocket bolts
     
    Camshaft sprocket and timing
     
    Engine mount through-bolts
     

  14.  
  15. Install 2 or 3 5 / 16 -18 bolts in the holes in the front of the camshaft and carefully pull the camshaft from the block.

    Click image to see an enlarged view

    Fig. Install 2 or 3 long bolts into the camshaft to use as a handle for easy removal or installation-7.4L engine shown, other engines similar

  16.  

To install:

  1. Liberally coat camshaft and bearing with heavy engine oil or engine assembly lubricant
  2.  
  3. Align the timing marks on the camshaft sprocket and crankshaft gears.
  4.  
  5. Install or connect the following:

    Camshaft
     
    Camshaft sprocket and chain. Torque the bolts to 25 ft. lbs. (34 Nm)
     
    Engine mount bolts
     
    Lifters and pushrods and adjust the valves
     
    Intake manifold
     
    Distributor using the locating marks made during removal
     
    Engine front cover
     
    Harmonic balancer and pulley
     
    Water pump
     
    Hoses at the water pump
     
    Valve covers
     
    Alternator, if removed
     
    Accessory belt, if removed
     
    Fan shroud and radiator
     
    Air conditioning condenser and compressor
     
    Grille and center support, if removed
     
    Air cleaner assembly
     
    Negative battery cable
     

  6.  
  7. Fill the cooling system with the proper type and quantity of antifreeze.
  8.  

8.1L Engine
  1. Properly discharge the air conditioning system.
  2.  
  3. Remove or disconnect the following:
    NOTE
    If any lifters are stuck in their bores, use a suitable valve lifter to remove them.


    WARNING
    All of the cam journals are the same size so be very careful when removing and installing the camshaft that you do not damage the bearings.



    Grille
     
    A/C condenser
     
    Intake manifold
     
    Rocker arms and pushrods
     
    Valve lifter guide retainer bolts and retainer
     
    Valve lifter guides, keeping them in proper order for reassembly
     
    Valve lifters
     
    Timing chain and sprocket
     
    Camshaft retaining bolts
     
    Camshaft retainer
     

  4.  
  5. Install three 8-1.25 x 100mm bolts in the holes in the front of the camshaft and carefully pull the camshaft from the block.

    Click image to see an enlarged view

    Fig. Use the 3 bolts as a handle to carefully remove and install the camshaft-8.1L engine shown

  6.  
  7. Remove the bolts from the front of the camshaft.
  8.  
  9. Clean and inspect the camshaft for damage.
  10.  

To install:

  1. Liberally coat camshaft and bearings with heavy engine oil or engine assembly lubricant.
  2.  
  3. Install the camshaft, using the 3 bolts threaded into the camshaft bolt holes as a handle, then remove the bolts.
    NOTE
    If a new camshaft is installed, you MUST install new valve lifters.

  4.  
  5. Install or connect the following:

    Camshaft retainer and bolts. Tighten to 106 inch lbs. (12 Nm).
     
    Timing chain and sprocket
     
    Valve lifters
     
    Valve lifter guides over the flats on the lifters. Make sure the rollers of the lifters are properly aligned with the cam lobes.
     
    Valve lifter guide retainer. Tighten the bolts to 18 ft. lbs. (25 Nm).
     
    Rocker arms and pushrods
     
    Intake manifold
     
    A/C condenser
     
    Grille
     

  6.  
  7. Recharge the A/C system.
  8.  

  1. Properly discharge the air conditioning system.
  2.  
  3. Remove or disconnect the following:
    NOTE
    If any lifters are stuck in their bores, use a suitable valve lifter to remove them.


    WARNING
    All of the cam journals are the same size so be very careful when removing and installing the camshaft that you do not damage the bearings.



    Grille
     
    A/C condenser
     
    Intake manifold
     
    Rocker arms and pushrods
     
    Valve lifter guide retainer bolts and retainer
     
    Valve lifter guides, keeping them in proper order for reassembly
     
    Valve lifters
     
    Timing chain and sprocket
     
    Camshaft retaining bolts
     
    Camshaft retainer
     

  4.  
  5. Install three 8-1.25 x 100mm bolts in the holes in the front of the camshaft and carefully pull the camshaft from the block.

    Click image to see an enlarged view

    Fig. Use the 3 bolts as a handle to carefully remove and install the camshaft-8.1L engines

  6.  
  7. Remove the bolts from the front of the camshaft.
  8.  
  9. Clean and inspect the camshaft for damage.
  10.  

To install:

  1. Liberally coat camshaft and bearings with heavy engine oil or engine assembly lubricant.
  2.  
  3. Install the camshaft, using the 3 bolts threaded into the camshaft bolt holes as a handle, then remove the bolts.
    NOTE
    If a new camshaft is installed, you MUST install new valve lifters.

  4.  
  5. Install or connect the following:

    Camshaft retainer and bolts. Tighten to 106 inch lbs. (12 Nm).
     
    Timing chain and sprocket
     
    Valve lifters
     
    Valve lifter guides over the flats on the lifters. Make sure the rollers of the lifters are properly aligned with the cam lobes.
     
    Valve lifter guide retainer. Tighten the bolts to 18 ft. lbs. (25 Nm).
     
    Rocker arms and pushrods
     
    Intake manifold
     
    A/C condenser
     
    Grille
     

  6.  
  7. Recharge the A/C system.
  8.  

 
label.common.footer.alt.autozoneLogo