Mazda B-Series 1998-06

Rocker Arms & Shafts

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Removal & Installation



2.3L & 2.5L Engines

A special tool is required to compress the valve spring.

  1. Remove the valve cover and associated parts as required.
  2.  
  3. Rotate the camshaft so that the base circle of the cam is against the cam follower you intend to remove.
  4.  



Click image to see an enlarged view

Fig. Use a special valve spring compressing tool to remove the follower

If removing more than one cam follower, label them so they can be returned to their original position.

  1. Using special tool 49-UN01-135 or equivalent, depress the valve spring, as necessary, and slide the cam follower over the lash adjuster and out from under the camshaft.
  2.  
  3. Install the cam follower in the reverse order of removal. Lubricate the followers with SAE 50W engine oil meeting current API specification prior to installing.
  4.  

2.3L Engine

This DOHC engine does not employ rocker arms. The camshafts bear directly on the lifters. For lifter removal, remove the camshafts.

2.5L Engine

NOTE
A special tool is required to compress the valve spring.

  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the valve cover.
  6.  
  7. Rotate the camshaft so that the base circle of the cam is against the cam follower you intend to remove.
    NOTE
    If removing more than one cam follower, label them so they can be returned to their original position.



    Click image to see an enlarged view

    Fig. To remove the cam follower (rocker arm), use the special tool to depress the valve spring, then remove the cam follower-2.5L engines

  8.  
  9. Using special tool T88T-6565-BH depress the valve spring. Slide the cam follower over the lash adjuster and out from under the camshaft.
  10.  

To install:

  1. Compress the valve spring and slide the roller follower into position.
  2.  
  3. Release the tension from the spring.
  4.  
  5. Install the valve cover and connect the negative battery cable.
  6.  

3.0L Engines
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Rocker arm covers
     
    Retaining bolt at each rocker arm
     

  4.  
  5. The rocker arm and pushrod may then be removed from the engine. Keep all rocker arms and pushrods in order so they may be installed in their original locations.

    Click image to see an enlarged view

    Fig. Exploded view of the rocker arm assembly-3.0L engine

  6.  

To install:

  1. Lubricate the rocker arm assemblies with SAE 50W engine oil.
  2.  
  3. Ensure that the fulcrums are properly seated into the cylinder head. Torque the rocker arm fulcrum bolts to 19 ft. lbs. (26 Nm).
  4.  
  5. Install the rocker arm covers and connect the negative battery cable.
  6.  

4.0L Engine
Disassembly & Reassembly
  1. Remove the spring washer and pin from each end of the valve rocker arm shaft.
  2.  
  3. Slide the rocker arms, springs and rocker arm shaft supports off the shaft. Be sure to mark the parts for re-assembly in the same locations.
  4.  
  5. If it is necessary to remove the plugs from each end of the shaft, drill or pierce the plug on one end. Use a steel rod to knock out the plug on the opposite end. Working from the open end, knock out the remaining plug.
  6.  
  7. The oil holes in the rocker arm shaft must point down when the shaft is installed. This position of the shaft can be recognized by a notch on the front face of the shaft.
  8.  
  9. If the plugs were removed from the shaft, use a blunt tool and install a plug, cup side out, in each end of the shaft.
  10.  
  11. Install a spring washer and pin on one end of the shaft, coat the rocker arm shaft with heavy engine oil and install the parts in the same sequence they were removed.
  12.  

OHV Engine
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Rocker arm covers
     
    Rocker arm shaft stand attaching bolts by loosening the bolts 2 turns at a time, in sequence (from the end of the shaft to the middle of the shaft)
     
    Rocker arm and shaft assembly
     

  4.  

To install:

  1. If equipped, loosen the valve lash adjusting screws a few turns. Apply engine oil to the assembly to provide initial lubrication.
  2.  
  3. Install or connect the following:

    Rocker arm shaft assembly to the cylinder head and guide adjusting screws on to the pushrods
     
    Rocker arm stand. Torque the bolts to 46-52 ft. lbs. (62-70 Nm), 2 turns at a time, in sequence (from middle of shaft to the end of the shaft).
     
    Rocker arm covers
     
    Negative battery cable

    Click image to see an enlarged view

    Fig. Rocker arm and shaft assembly-4.0L engine

     

  4.  

SOHC Engines

NOTE
A special tool is required to compress the valve spring.

  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the valve cover.
  6.  
  7. Rotate the camshaft so that the base circle of the cam is against the cam follower you intend to remove.
    NOTE
    If removing more than one cam follower, label them so they can be returned to their original position.



    Click image to see an enlarged view

    Fig. Rocker arm and shaft assembly-4.0L SOHC engine

  8.  
  9. Using special tool T97T-6565-A depress the valve spring. Slide the cam follower over the lash adjuster and out from under the camshaft.
  10.  

To install:

  1. Compress the valve spring and slide the roller follower into position.
  2.  
  3. Release the tension from the spring.
  4.  
  5. Install the valve cover and connect the negative battery cable.
  6.  

Left Bank
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable.
    NOTE
    On some vehicles, when the battery cable is disconnected and reconnected, some abnormal drive symptoms may occur while the vehicle relearns its adaptive strategy. The vehicle may need to be driven to relearn its strategy.

  4.  
  5. Remove the upper intake manifold.
  6.  
  7. Disconnect the left side spark plug wire holders. Disconnect the engine control harness from the valve cover.
  8.  
  9. Remove the three bolts and the five stud bolts. Remove the valve cover from the engine. Discard the gasket.
    NOTE
    To prevent stretching the valve cover gasket, loosen silicone gasket and sealant from the cylinder head by sliding a flat knife between the valve cover gasket and the cylinder head.

  10.  
  11. Remove the retaining bolt at each rocker arm.
  12.  
  13. The rocker arm and pushrod may then be removed from the engine. Keep all rocker arms and pushrods in order so they may be installed in their original locations.
  14.  

To install:

  1. Be sure to clean all old gasketing material from the sealing surfaces, using the proper tools. Do not use metal scrappers, wire brushes, power abrasive discs or other abrasive means to clean the sealing areas.
  2.  
  3. Installation is the reverse of the removal procedure.
  4.  
  5. Be sure to use a new valve cover gasket. Apply a bead of silicone gasket and sealant in two places where the cylinder head and lower intake manifold meet. The valve cover must be installed within 4 minutes of application.
  6.  
  7. Tighten the valve cover retaining bolts to 9 ft. lbs. in the proper sequence.
  8.  
  9. Lubricate the rocker arm assemblies with SAE 50W engine oil.
  10.  
  11. Ensure that the fulcrums are properly seated into the cylinder head. Torque the rocker arm fulcrum bolts to 19 ft. lbs. (26 Nm).
  12.  

Right Bank
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable.
    NOTE
    On some vehicles, when the battery cable is disconnected and reconnected, some abnormal drive symptoms may occur while the vehicle relearns its adaptive strategy. The vehicle may need to be driven to relearn its strategy.

  4.  
  5. Disconnect the ignition coil electrical connector. Disconnect the spark plug wires.
  6.  
  7. Disconnect the heater hose support from the stud. Disconnect the engine control sensor wiring from the IAT sensor.
  8.  
  9. Disconnect the engine control sensor wiring from the MAF sensor. Position the engine control sensor wiring aside.
  10.  
  11. Disconnect the vacuum hose. Disconnect the engine control wire harness from the valve cover studs. Disconnect the PCV valve tube.
  12.  
  13. Remove the valve cover retaining bolts. Remove the valve cover from the engine. Discard the gasket.
    NOTE
    To prevent stretching the valve cover gasket, loosen silicone gasket and sealant from the cylinder head by sliding a flat knife between the valve cover gasket and the cylinder head.

  14.  
  15. Remove the retaining bolt at each rocker arm.
  16.  
  17. The rocker arm and pushrod may then be removed from the engine. Keep all rocker arms and pushrods in order so they may be installed in their original locations.
  18.  

To install:

  1. Be sure to clean all old gasketing material from the sealing surfaces, using the proper tools. Do not use metal scrappers, wire brushes, power abrasive discs or other abrasive means to clean the sealing areas.
  2.  
  3. Installation is the reverse of the removal procedure.
  4.  
  5. Be sure to use a new valve cover gasket. Apply a bead of silicone gasket and sealant in two places where the cylinder head and lower intake manifold meet. The valve cover must be installed within 4 minutes of application.
  6.  
  7. Tighten the valve cover retaining bolts to 9 ft. lbs. in the proper sequence.
  8.  
  9. Lubricate the rocker arm assemblies with SAE 50W engine oil.
  10.  
  11. Ensure that the fulcrums are properly seated into the cylinder head. Torque the rocker arm fulcrum bolts to 19 ft. lbs. (26 Nm).

    Click image to see an enlarged view

    Fig. Rocker arm and related components-3.0L engine



    Click image to see an enlarged view

    Fig. Valve cover bolt torque sequence-3.0L engine

  12.  

 
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