Nissan Frontier, Xterra 1998-05

Valve Lash (Clearance) Adjustment

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These engines are equipped with hydraulic valve lifters that do not require periodic adjustment.

2.4L Engine




NOTE
Measure valve clearance with the engine warm.

  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove the valve cover.
  4.  
  5. Set the engine to the top of the compression stroke with the valves closed for the cylinder to be measured.
  6.  
  7. Check the valve clearance. The valve clearance specifications are as follows:

    Intake: 0.012-0.015 in. (0.31-0.39mm)
     
    Exhaust: 0.013-0.016 in. (0.33-0.41mm)
     

  8.  
  9. If adjustment is necessary, compress the valve spring with ToolAB
  10.  
  11. Replace the shims as necessary to achieve the correct valve clearance.
  12.  
  13. Repeat for each valve to be adjusted.
  14.  


    Click image to see an enlarged view

    Fig. Valve adjustment tools (A) and (B)-2.4L engine



NOTE
Measure valve clearance with the engine warm.

  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Remove the valve cover.
  4.  
  5. Set the engine to the top of the compression stroke with the valves closed for the cylinder to be measured.
  6.  
  7. Check the valve clearance. The valve clearance specifications are as follows:

    Intake: 0.012-0.015 in. (0.31-0.39mm)
     
    Exhaust: 0.013-0.016 in. (0.33-0.41mm)
     

  8.  
  9. If adjustment is necessary, compress the valve spring with Tool A and insert Tool B to hold the valve in the open position as shown.

    Click image to see an enlarged view

    Fig. Valve adjustment tools (A) and (B)-2.4L engine

  10.  
  11. Replace the shims as necessary to achieve the correct valve clearance.
  12.  
  13. Repeat for each valve to be adjusted.
  14.  


NOTE
Measure valve clearance with the engine warm.

  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Remove the valve cover.
  4.  
  5. Set the engine to the top of the compression stroke with the valves closed for the cylinder to be measured.
  6.  
  7. Check the valve clearance. The valve clearance specifications are as follows:

    Intake: 0.012-0.015 in. (0.31-0.39mm)
     
    Exhaust: 0.013-0.016 in. (0.33-0.41mm)
     

  8.  
  9. If adjustment is necessary, compress the valve spring with Tool A and insert Tool B to hold the valve in the open position as shown.

    Click image to see an enlarged view

    Fig. Valve adjustment tools (A) and (B)-2.4L engine

  10.  
  11. Replace the shims as necessary to achieve the correct valve clearance.
  12.  
  13. Repeat for each valve to be adjusted.
  14.  


NOTE
Measure valve clearance with the engine warm.

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Remove the valve cover.
  4.  
  5. Set the engine to the top of the compression stroke with the valves closed for the cylinder to be measured.
  6.  
  7. Check the valve clearance. The valve clearance specifications are as follows:

    Intake: 0.012-0.015 in. (0.31-0.39mm)
     
    Exhaust: 0.013-0.016 in. (0.33-0.41mm)
     

  8.  
  9. If adjustment is necessary, compress the valve spring with Tool A and insert Tool B to hold the valve in the open position as shown.

    Click image to see an enlarged view

    Fig. Valve adjustment tools (A) and (B)-2.4L engine

  10.  
  11. Replace the shims as necessary to achieve the correct valve clearance.
  12.  
  13. Repeat for each valve to be adjusted.
  14.  

4.0L Engines



  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable. Remove the engine under cover.
  4.  
  5. Remove the intake manifold collector.
  6.  
  7. Separate the engine harness and remove their brackets from the rocker covers. Remove the harness bracket from the cylinder head, if necessary.
  8.  
  9. Remove the ignition coil. Remove the PCV hoses. Remove the oil filler cap, if necessary.
  10.  
  11. Loosen the rocker cover retaining bolts, in the reverse order of the tightening sequence.
  12.  
  13. Remove the rocker covers from the engine.
  14.  
  15. Set the No.1 cylinder at TDC of its compression stroke by rotating the crankshaft pulley clockwise to align the timing mark (grooved line without color) with the timing indicator. Make sure that the intake and exhaust cam noses on No.1 cylinder (engine front side on right bank) are in alignment as shown in the illustration. If not, rotate the crankshaft in the clockwise direction 360 degrees.

    Click image to see an enlarged view

    Fig. No.1 cylinder at TDC (compression stroke)-4.0L engine

  16.  
  17. Use a feeler gauge and measure the clearance between the valve lifter and the camshaft.
  18.  
  19. With the No.1 piston at TDC, refer to the illustration and measure the valve clearances at the locations marked with an -X-. The -X- locations are indicated in the illustration with an arrow.

    Click image to see an enlarged view

    Fig. Valve adjustment measurement No.1 cylinder at TDC (compression stroke)-4.0L engine

  20.  
  21. Rotate the crankshaft pulley clockwise 240 degrees (when viewed from the engine front) to align No.3 cylinder at TDC on the compression stroke.
    NOTE
    The crankshaft pulley bolt flange has a stamped line every 60 degrees, which can be used as a guide to rotation angle.

  22.  
  23. With the No.3 piston at TDC, refer to the illustration and measure the valve clearances at the locations marked with an -X-. The -X- locations are indicated in the illustration with an arrow.

    Click image to see an enlarged view

    Fig. Valve adjustment measurement No.3 cylinder at TDC (compression stroke)-4.0L engine

  24.  
  25. Rotate the crankshaft pulley clockwise 240 degrees (when viewed from the engine front) to align No.5 cylinder at TDC on the compression stroke.
    NOTE
    The crankshaft pulley bolt flange has a stamped line every 60 degrees, which can be used as a guide to rotation angle.

  26.  
  27. With the No.5 piston at TDC, refer to the illustration and measure the valve clearances at the locations marked with an -X-. The -X- locations are indicated in the illustration with an arrow.

    Click image to see an enlarged view

    Fig. Valve adjustment measurement No.5 cylinder at TDC (compression stroke)-4.0L engine

  28.  
  29. If measurements are not within specification, proceed to the next step.
  30.  
  31. Remove the camshaft. Remove the valve lifters that are not within specification.
  32.  
  33. Measure the center thickness of the removed lifters, using a micrometer.
  34.  
  35. Use the equation (t=t1+(C1-C2) to calculate valve lifter thickness for replacement.
    NOTE
    t= valve lifter thickness to be replaced. t1= removed valve lifter thickness. C1= measured valve clearance. C2= standard valve clearance.

  36.  
  37. Intake valve lifter thickness of the new valve lifter can be identified by the stamp mark on the reverse side (inside the cylinder). The stamp mark -788U- indicates 7.88 mm (0.3102 inch) thickness.
    NOTE
    Available thickness of a valve lifter ranges from 7.88-8.40 mm (0.3102-0.3307 inch) in steps of 0.02 mm (0.0008 inch). There are 27 different sizes.

  38.  
  39. Exhaust valve lifter thickness of the new valve lifter can be identified by the stamp mark on the reverse side (inside the cylinder). The stamp mark -N788- indicates 7.88 mm (0.3102 inch) thickness.
    NOTE
    Available thickness of a valve lifter ranges from 7.88-8.36 mm (0.3102-0.3291 inch) in steps of 0.02 mm (0.0008 inch). There are 25 different sizes.

  40.  
  41. Install the selected valve lifters.
  42.  
  43. Install the camshaft.
  44.  
  45. Manually rotate the crankshaft pulley in the clockwise direction a few rotations.
  46.  
  47. Check the valve clearance and be sure it is within specification.
  48.  
  49. When installing the rocker cover, apply liquid gasket, be sure to use genuine RTV silicone sealant or equivalent, to the positions shown in the illustration. Refer to figure -a- to apply liquid gasket to joint part of camshaft bracket No.1 and cylinder head. Refer to figure -b- to apply liquid gasket to the figure -a- squarely.
  50.  
  51. Install the rocker cover. Torque the retaining bolts to 17 inch lbs and than to 74 inch lbs, in the proper sequence.
  52.  
  53. Continue the installation in the reverse of the removal procedure.
  54.  

5.0L Engine



  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable. Drain the cooling system.
  4.  
  5. Remove the intake manifold.
  6.  
  7. Disconnect the PCV hose from the rocker cover. Remove the ignition coil.
  8.  
  9. Remove the PCV valve and O-ring from the rocker cover, if necessary.
  10.  
  11. Remove the oil filler cap from the rocker cover, if necessary.
  12.  
  13. Remove the rocker cover retaining bolts. Be sure to remove the bolts by reversing the order of the tightening torque sequence.
  14.  
  15. Remove the rocker cover. Discard the gasket.
  16.  
  17. Remove the undercover. Remove the lower radiator shroud.
  18.  
  19. Set the No.1 cylinder at TDC of its compression stroke by rotating the crankshaft pulley clockwise to align the TDC mark to the timing indicator on the front cover. At the same time make sure that both the intake and exhaust cam noses of the NO.1 cylinder face outward, as indicated by the arrows in the illustration. If not, rotate the crankshaft in the clockwise direction 360 degrees.

    Click image to see an enlarged view

    Fig. No.1 cylinder at TDC (compression stroke)-2.5L engine

  20.  
  21. Use a feeler gauge and measure the clearance between the valve lifter and the camshaft.
  22.  
  23. With the No.1 piston at TDC, refer to the illustration and measure the valve clearances at the locations marked with an -X-. The -X- locations are indicated in the illustration with an arrow.

    Click image to see an enlarged view

    Fig. Valve adjustment measurement No.1 cylinder at TDC (compression stroke)-2.5L engine

  24.  
  25. Rotate the crankshaft pulley clockwise 360 degrees and align the TDC mark to the timing indicator on the front cover.
  26.  
  27. With the No.4 piston at TDC, refer to the illustration and measure the valve clearances at the locations marked with an -X-. The -X- locations are indicated in the illustration with an arrow.

    Click image to see an enlarged view

    Fig. Valve adjustment measurement No.4 cylinder at TDC (compression stroke)-2.5L engine

  28.  
  29. If measurements are not within specification, proceed to the next step.
  30.  
  31. Remove the camshaft. Remove the valve lifters that are not within specification.
  32.  
  33. Measure the center thickness of the removed lifters, using a micrometer.
  34.  
  35. Use the equation (t=t1+(C1-C2) to calculate valve lifter thickness for replacement.
    NOTE
    t= valve lifter thickness to be replaced. t1= removed valve lifter thickness. C1= measured valve clearance. C2= standard valve clearance.

  36.  
  37. Thickness of the new valve lifter can be identified by the stamp mark on the reverse side (inside the cylinder). The stamp mark -696- indicates 6.96 mm (0.2740 inch) thickness.
    NOTE
    Available thickness of a valve lifter ranges from 6.96-7.46 mm (0.2740-0.2937 inch) in steps of 0.02 mm (0.0008 inch). There are 26 different sizes.

  38.  
  39. Install the selected valve lifters.
  40.  
  41. Install the camshaft.
  42.  
  43. Manually rotate the crankshaft pulley in the clockwise direction a few rotations.
  44.  
  45. Check the valve clearance and be sure it is within specification.
  46.  
  47. When installing the rocker cover, apply liquid gasket, be sure to use genuine RTV silicone sealant or equivalent, to the positions shown in the illustration. Refer to figure -a- to apply liquid gasket to joint part of camshaft bracket No.1 and cylinder head. Refer to figure -b- to apply liquid gasket in 90 degrees to figure -b-.
  48.  
  49. Install the rocker cover. Torque the retaining bolts to 18 inch lbs and than to 73 inch lbs, in the proper sequence.
  50.  
  51. Continue the installation in the reverse of the removal procedure.
  52.  

 
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