CYLINDER HEAD INSPECTION

PROCEDURE


  1. INSPECT CYLINDER HEAD FOR FLATNESS


    1. Using a precision straightedge and feeler gauge, measure the warpage of the contact surfaces where the cylinder head contacts the cylinder block and manifolds.

      A0052MLE01
      *1 Intake Manifold Side:
      *2 Cylinder Block Side:
      *3 Exhaust Manifold Side:
      Maximum Warpage
      Item Specified Condition
      Cylinder block side 0.05 mm (0.00197 in.)
      Intake manifold side 0.10 mm (0.00394 in.)
      Exhaust manifold side 0.10 mm (0.00394 in.)

      If the warpage is more than the maximum, replace the cylinder head.

  2. INSPECT CYLINDER HEAD FOR CRACKS


    1. A00563N

      Using a dye penetrant, check the intake ports, exhaust ports and cylinder surface for cracks.

      If cracked, replace the cylinder head.

  3. INSPECT VALVE SEATS


    1. A0054SNE01
      *1 Width

      Apply a light coat of Prussian blue to the valve face.

    2. Lightly press the valve face against the valve seat.

      Tech Tips

      Do not rotate the valve while pressing the valve.

    3. Check the valve face and valve seat.


      1. Intake Side:

        Check that the contact surfaces of the valve seat and valve face are in the middle area of their respective surfaces, with the width between 1.0 and 1.4 mm (0.0394 and 0.0551 in.).

        If not, correct the valve seat.

      2. Exhaust Side:

        Check that the contact surfaces of the valve seat and valve face are in the middle area of their respective surfaces, with the width between 1.0 and 1.4 mm (0.0394 and 0.0551 in.).

        If not, correct the valve seat.

      3. Check that the contact surfaces of the valve seat and valve face are even around the entire valve seat.

        If not, correct the valve seat.

  4. INSPECT CAMSHAFT THRUST CLEARANCE


    1. Install the camshaft housing assembly Click here.

      Tech Tips

      Do not use seal packing when installing the camshaft housing, as the installation is temporary.

    2. A00575P

      Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.

      Standard thrust clearance
      0.06 to 0.155 mm (0.00236 to 0.00610 in.)
      Maximum thrust clearance
      0.17 mm (0.00669 in.)

      If the thrust clearance is more than the maximum, replace the camshaft housing sub-assembly.

  5. INSPECT COMPRESSION SPRING

    Tech Tips

    Type A and type B can be distinguished by the shape of the inner compression spring.

    A0054C9E03
    Type Shape of the Inner Compression Spring
    A Straight
    B Taper

    1. for Type A:


      1. A0057KH

        Using a vernier caliper, measure the free length of the compression spring.

        Standard free length
        53.87 mm (2.12 in.)

        If the free length is not as specified, replace the compression spring.

      2. A0055MX

        Using a steel square, measure the deviation of the compression spring.

        Maximum deviation
        1.0 mm (0.0394 in.)

        If the deviation is more than the maximum, replace the compression spring.

    2. for Type B:


      1. A00586O

        Using a vernier caliper, measure the free length of the compression spring.

        Standard free length
        51.9 mm (2.04 in.)

        If the free length is not as specified, replace the compression spring.

      2. A0056AIE28
        *1 Deviation
        *2 37.5 mm (1.48 in.)

        Using a steel square, measure the deviation of the compression spring at the position shown in the illustration.

        Maximum deviation
        1.3 mm (0.0512 in.)

        If the deviation is more than the maximum, replace the compression spring.

  6. INSPECT INTAKE VALVE


    1. A0058DME01
      *1 Overall Length

      Using a vernier caliper, measure the overall length of the valve.

      Standard overall length
      109.34 mm (4.30 in.)
      Minimum overall length
      108.84 mm (4.29 in.)

      If the overall length is less than the minimum, replace the valve.

    2. A0055T9

      Using a micrometer, measure the diameter of the valve stem.

      Valve stem diameter
      5.470 to 5.485 mm (0.215 to 0.216 in.)

      If the valve stem diameter is not as specified, check the oil clearance.

    3. A00532KE01
      *1 Margin Thickness

      Using a vernier caliper, measure the valve head margin thickness.

      Standard margin thickness
      1.0 mm (0.0394 in.)
      Minimum margin thickness
      0.5 mm (0.0197 in.)

      If the margin thickness is less than the minimum, replace the valve.

  7. INSPECT EXHAUST VALVE


    1. A0057SIE01
      *1 Overall Length

      Using a vernier caliper, measure the overall length of the valve.

      Standard overall length
      108.25 mm (4.26 in.)
      Minimum overall length
      107.75 mm (4.24 in.)

      If the overall length is less than the minimum, replace the valve.

    2. A0058N9

      Using a micrometer, measure the diameter of the valve stem.

      Valve stem diameter
      5.465 to 5.480 mm (0.215 to 0.216 in.)

      If the valve stem diameter is not as specified, check the oil clearance.

    3. A0052JIE25
      *1 Margin Thickness

      Using a vernier caliper, measure the valve head margin thickness.

      Standard margin thickness
      1.0 mm (0.0394 in.)
      Minimum margin thickness
      0.5 mm (0.0197 in.)

      If the margin thickness is less than the minimum, replace the valve.

  8. INSPECT VALVE GUIDE BUSH OIL CLEARANCE


    1. A0058FY

      Using a caliper gauge, measure the inside diameter of the guide bush.

      Standard bushing inside diameter
      5.510 to 5.530 mm (0.217 to 0.218 in.)

    2. Subtract the valve stem diameter measurement from the guide bush inside diameter measurement.

      Standard Oil Clearance
      Item Specified Condition
      Intake 0.025 to 0.060 mm (0.000984 to 0.00236 in.)
      Exhaust 0.030 to 0.065 mm (0.00118 to 0.00256 in.)
      Maximum Oil Clearance
      Item Specified Condition
      Intake 0.080 mm (0.00315 in.)
      Exhaust 0.085 mm (0.00335 in.)

      If the clearance is more than the maximum, replace the valve and guide bush.