Mazda Trucks 1987-1993 Repair Guide

Rocker Arms/Shafts

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REMOVAL AND INSTALLATION



2.2L Engine

See Figures 1 and 2

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner assembly or air intake hose, as required.
  4.  
  5. Remove the rocker arm cover.
  6.  



Click image to see an enlarged view

Fig. Fig. 1: Rocker arm/shaft assembly mounting bolt removal sequence

  1. Loosen the rocker arm/shaft assembly mounting bolts in 2-3 steps in the proper sequence. Remove the rocker arm/shaft assembly together with the bolts.
  2.  
  3. If necessary, disassemble the rocker arm/shaft assembly, noting the position of each component to ease reassembly.
  4.  
  5. Check for wear or damage to the contact surfaces of the shafts and rocker arms; replace as necessary.
  6.  
  7. Measure the rocker arm inner diameter, it should be 0.6300-0.6310 in. (16.000-16.027mm). Measure the rocker arm shaft diameter, it should be 0.6286-0.6293 in. (15.966-15.984mm).
  8.  
  9. Subtract the shaft diameter from the rocker arm diameter to get the oil clearance. The oil clearance should be 0.0006-0.0024 in. (0.016-0.061mm) and should not exceed 0.004 in. (0.10mm). Replace parts, as necessary, if the oil clearance is not within specification.
  10.  

To install:
  1. Apply clean engine oil to the rocker arm shafts and rocker arms and assemble the rocker arm/shaft assembly in the reverse order of disassembly. Make sure the rocker arm shaft oil holes in the center camshaft cap face each other.
  2.  

Use the mounting bolts for alignment.

  1. Apply silicone sealant to the cylinder head on the front and rear camshaft cap mounting surface. Apply clean engine oil to the camshaft journals and valve stem tips.
  2.  



Click image to see an enlarged view

Fig. Fig. 2: Rocker arm/shaft assembly mounting bolt tightening sequence

  1. Install the rocker arm/shaft assembly and tighten the bolts, in sequence, in 2-3 steps to a maximum torque of 13-20 ft. lbs. (18-26 Nm).
  2.  
  3. Apply silicone sealant to each side of the front and rear camshaft cap and the cylinder head in the area where the caps meet the cylinder head.
  4.  
  5. Install the rocker arm cover and tighten the mounting bolts to 26-35 inch lbs. (3-4 Nm).
  6.  
  7. Install the air cleaner assembly or air intake tube. Connect the negative battery cable, start the engine and check for leaks and proper operation.
  8.  

2.6L Engine 1987-88

See Figure 3

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner assembly.
  4.  
  5. Remove the rocker arm cover.
  6.  
  7. Install hydraulic lash adjuster holder tool 49 U012 001 or equivalent, over the ends of each rocker arm to keep the hydraulic lash adjuster from falling out when the rocker arm/shaft assembly is removed.
  8.  
  9. Loosen the rocker arm/shaft assembly mounting bolts and remove the assembly. Leave the mounting bolts in place in the shaft to keep the assembly together, if there will be no further disassembly.
  10.  
  11. If necessary, disassemble the rocker arm/shaft assembly, noting the position of each component to ease reassembly.
  12.  
  13. Check for wear or damage to the contact surfaces of the shafts and rocker arms; replace as necessary.
  14.  
  15. Measure the rocker arm inner diameter, it should be 0.7445-0.7452 in. (18.910-18.928mm). Measure the rocker arm shaft diameter, it should be 0.7435-0.7440 in. (18.885-18.898mm).
  16.  
  17. Subtract the shaft diameter from the rocker arm diameter to get the oil clearance. The oil clearance should be 0.0005-0.0017 in. (0.012-0.043mm) and should not exceed 0.004 in. (0.10mm). Replace parts, as necessary, if the oil clearance is not within specification.
  18.  

To install:
  1. Apply clean engine oil to the rocker arm shafts and rocker arms and assemble the rocker arm/shaft assembly in the reverse order of disassembly. Be sure to align the mating mark on the front of the shaft with the mating mark on the front camshaft cap.
  2.  
  3. Apply clean engine oil to the camshaft journals and valve stem tips.
  4.  



Click image to see an enlarged view

Fig. Fig. 3: Rocker arm/shaft assembly mounting bolt tightening sequence

  1. Install the rocker arm/shaft assembly and tighten the mounting bolts, in sequence, in 2-3 steps to a maximum torque of 14-15 ft. lbs. (19-20 Nm).
  2.  
  3. Remove the hydraulic lash adjuster holder tools. Adjust the jet valve lash.
  4.  
  5. Install the rocker arm cover and tighten to 43-61 inch lbs. (5-7 Nm). Install the air cleaner assembly.
  6.  
  7. Connect the negative battery cable, start the engine and bring to normal operating temperature. Check for leaks and proper operation. With the engine warm, readjust the jet valve clearance.
  8.  

2.6L Engine 1989-93

See Figures 4 and 5

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air intake hose.
  4.  
  5. Remove the rocker arm cover.
  6.  



Click image to see an enlarged view

Fig. Fig. 4: Rocker arm/shaft assembly mounting bolt removal sequence

  1. Loosen the rocker arm/shaft assembly mounting bolts in 2-3 steps in the proper sequence. Remove the rocker arm/shaft assembly together with the bolts.
  2.  
  3. If necessary, disassemble the rocker arm/shaft assembly, noting the position of each component to ease reassembly.
  4.  
  5. Check for wear or damage to the contact surfaces of the shafts and rocker arms; replace as necessary.
  6.  
  7. Measure the rocker arm inner diameter, it should be 0.8268-0.8281 in. (21.000-21.033mm). Measure the rocker arm shaft diameter, it should be 0.8252-0.8260 in. (20.959-20.980mm).
  8.  
  9. Subtract the shaft diameter from the rocker arm diameter to get the oil clearance. The oil clearance should be 0.0008-0.0029 in. (0.020-0.074mm) and should not exceed 0.004 in. (0.10mm). Replace parts, as necessary, if the oil clearance is not within specification.
  10.  

To install:
  1. Apply clean engine oil to the rocker arm shafts and rocker arms and assemble the rocker arm/shaft assembly in the reverse order of disassembly, noting the following:
    1. The intake side shaft has twice as many oil holes as the exhaust side shaft.
    2.  
    3. The No. 4 camshaft cap has an oil hole from the cylinder head; make sure it is installed correctly.
    4.  

  2.  
  3. Apply clean engine oil to the camshaft journals and valve stem tips.
  4.  



Click image to see an enlarged view

Fig. Fig. 5: Rocker arm/shaft assembly mounting bolt tightening sequence

  1. Install the rocker arm/shaft assembly and tighten the mounting bolts, in sequence, in 2-3 steps to a maximum torque of 14-19 ft. lbs. (19-25 Nm).
  2.  
  3. Coat a new gasket with silicone sealer and install on the rocker arm cover. Apply sealer to the cylinder head in the area of the half circle seals and install the rocker arm cover. Install the mounting bolts and tighten to 52-78 inch lbs. (6-9 Nm).
  4.  
  5. Install the air intake hose. Connect the negative battery cable, start the engine and check for leaks and proper operation.
  6.  

3.0L Engine

See Figures 6 and 7

  1. Disconnect the negative battery cable.
  2.  
  3. If removing the driver's side rocker arm/shaft assembly, proceed as follows:
    1. Remove the air inlet tube.
    2.  
    3. Disconnect the necessary electrical connectors and vacuum hoses from the throttle body and intake air pipe.
    4.  
    5. Disconnect the throttle cable.
    6.  
    7. Remove the throttle body and intake air pipe.
    8.  

  4.  
  5. Remove the rocker arm cover.
  6.  



Click image to see an enlarged view

Fig. Fig. 6: Rocker arm/shaft assembly mounting bolt removal sequence

  1. Loosen the rocker arm/shaft assembly mounting bolts in sequence, in 2-3 steps. Remove the assembly with the bolts.
  2.  
  3. If necessary, disassemble the rocker arm/shaft assembly, noting the position of each component to ease reassembly.
  4.  
  5. Check for wear or damage to the contact surfaces of the shafts and rocker arms; replace as necessary.
  6.  
  7. Measure the rocker arm inner diameter, it should be 0.7480-0.7493 in. (19.000-19.033mm). Measure the rocker arm shaft diameter, it should be 0.7464-0.7472 in. (18.959-18.980mm).
  8.  
  9. Subtract the shaft diameter from the rocker arm diameter to get the oil clearance. The oil clearance should be 0.0008-0.0029 in. (0.020-0.074mm) and should not exceed 0.004 in. (0.10mm). Replace parts, as necessary, if the oil clearance is not within specification.
  10.  

To install:
  1. Apply clean engine oil to the rocker arm shafts and rocker arms and assemble the rocker arm/shaft assembly in the reverse order of disassembly, noting the following. The intake side shaft has twice as many oil holes as the exhaust side shaft.
  2.  
  3. Apply clean engine oil to the camshaft journals and valve stem tips.
  4.  



Click image to see an enlarged view

Fig. Fig. 7: Rocker arm/shaft assembly mounting bolt tightening sequence

  1. Install the rocker arm/shaft assembly and tighten the mounting bolts, in sequence, in 2-3 steps to a maximum torque of 14-19 ft. lbs. (19-25 Nm).
  2.  

Be careful that the rocker arm shaft spring does not get caught between the shaft and mounting boss during installation.

  1. Coat a new gasket with silicone sealant and install on the rocker arm cover. Install the rocker arm cover with new seal washers and tighten the bolts to 30-39 inch lbs. (3-4 Nm).
  2.  
  3. Install the intake air pipe, throttle body and air intake tube, if removed. Connect the throttle cable and the necessary electrical connectors and vacuum hoses.
  4.  
  5. Connect the negative battery cable, start the engine and check for leaks and proper operation.
  6.  

4.0L Engine

See Figure 8

  1. Disconnect the negative battery cable. Remove the intake shield and air intake tube.
  2.  
  3. If removing the right rocker arm/shaft assembly, proceed as follows:
    1. Remove the alternator and the coil pack.
    2.  
    3. Remove the retaining bolt from the air conditioning pipe over the upper intake manifold.
    4.  
    5. Remove the spark plug wires from the clips on the valve cover.
    6.  
    7. Remove the 2 wiring harnesses from the right rocker arm cover.
    8.  
    9. Disconnect the vacuum hose at the coupling over the rocker arm cover.
    10.  
    11. Remove the engine wiring harness clip from the rocker arm cover-to-intake manifold stud. Do not pull on the harness but rather lift up on the clip.
    12.  
    13. Remove the right rocker arm cover bolts, reinforcement plate and the cover.
    14.  

  4.  
  5. If removing the right rocker arm/shaft assembly, proceed as follows:
    1. Remove the bolt from the air conditioning pipe over the upper intake manifold, if not already done.
    2.  
    3. Disconnect the air conditioning compressor clutch connector and remove the wiring harness from the back of the compressor.
    4.  
    5. Remove the air conditioning compressor bolts, pull up the tube that goes around the back of the engine and reposition the compressor and tube aside.
    6.  
    7. Tag and disconnect the power brake vacuum hose and other hoses from the vacuum tee on the plenum.
    8.  
    9. Remove the PCV hose and valve. Remove the wiring harness from the valve cover and position aside.
    10.  
    11. Tag and disconnect the spark plug wires from the spark plugs and clips on the rocker arm cover.
    12.  
    13. Remove the engine wiring harness clip from the rocker arm cover-to-intake manifold stud. Do not pull on the harness but rather lift up on the clip.
    14.  
    15. Remove the retaining bolt from the fuel hose clip to the front of the engine to allow the fuel hoses to be moved enough to gain access to the upper front rocker arm cover bolt.
    16.  
    17. Remove the bolts, reinforcement plates and left rocker arm cover.
    18.  

  6.  
  7. Remove the rocker arm shafts by loosening the support bolts 2 turns at a time until the shaft can be removed.
  8.  
  9. If necessary, disassemble the rocker arm/shaft assembly by removing the spring washer and pin from each end of the shaft and sliding the rocker arms, springs and rocker arm shaft supports off the shaft. Note the position of each component to ease reassembly.
  10.  
  11. Inspect all components for wear and replace, as necessary.
  12.  

To install:


Click image to see an enlarged view

Fig. Fig. 8: Rocker arm/shaft assembly installation

  1. Coat the rocker arms and shafts with clean engine oil and reassemble. The oil holes in the shaft must point down when the shaft is installed. This position can be recognized by a notch on the front face of the shaft.
  2.  
  3. Lubricate the pushrod ends and valve stem tips.
  4.  
  5. Install the rocker arm/shaft assembly and draw the shaft support bolts down evenly, 2 turns at a time, until the rocker arm/shaft assembly is fully down. Tighten the shaft support bolts to 46-52 ft. lbs. (62-70 Nm).
  6.  
  7. Clean all gasket mating surfaces.
  8.  
  9. Apply silicone sealant to the intake manifold-to-cylinder head parting seam and an 1 / 8 in. ball of sealer to the rocker arm cover bolt holes on the exhaust side.
  10.  
  11. Install a new gasket on the rocker arm cover and install the cover, reinforcing plates and bolts. Tighten the bolts to 53-70 inch lbs. (6-8 Nm) working in a criss-cross pattern and starting at the center bolts.
  12.  
  13. Install the remaining components. Connect the negative battery cable, start the engine and check for leaks and proper operation.
  14.  

 
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