CYLINDER HEAD INSPECTION

PROCEDURE


  1. INSPECT CYLINDER HEAD FOR FLATNESS


    1. Using a precision straightedge and feeler gauge, check the surfaces which contact the cylinder block sub-assembly and manifolds for warpage.

      A01TAAEC01
      *a Cylinder Block Side *b Intake Manifold Side
      *c 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 greater than the maximum, replace the cylinder head sub-assembly.

  2. INSPECT CYLINDER HEAD FOR CRACKS


    1. A01TA0D

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

      If cracked, replace the cylinder head sub-assembly.

  3. INSPECT VALVE SEATS


    1. A01TAO3C07
      *a 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, resurface 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, resurface 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, resurface the valve seat.

  4. INSPECT CAMSHAFT THRUST CLEARANCE


    1. Install the camshafts.

      Click here

    2. A01TA2N

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

      Standard Thrust Clearance
      Item Specified Condition
      Intake 0.06 to 0.155 mm (0.00236 to 0.00610 in.)
      Exhaust 0.06 to 0.155 mm (0.00236 to 0.00610 in.)
      Maximum Thrust Clearance
      Item Specified Condition
      Intake 0.17 mm (0.00669 in.)
      Exhaust 0.17 mm (0.00669 in.)

      If the thrust clearance is greater than the maximum, replace the camshaft housing. If the thrust surface is damaged, replace the camshaft.

  5. INSPECT CAMSHAFT OIL CLEARANCE


    1. Clean the bearing caps and camshaft journals.

    2. Place the camshafts on the camshaft housing.

    3. A01TBJHC06
      *a Plastigage

      Lay a strip of Plastigage across each camshaft journal.

    4. Install the camshaft bearing caps.

      Click here

      Note

      Do not turn the camshaft.

    5. Remove the camshaft bearing caps.

      Click here

    6. A01TCOHC02
      *a Plastigage

      Measure the Plastigage at its widest point.

      Standard Oil Clearance
      Item Specified Condition
      Camshaft No. 1 journal 0.030 to 0.063 mm (0.00118 to 0.00248 in.)
      Camshaft other journals 0.035 to 0.072 mm (0.00138 to 0.00283 in.)
      Maximum Oil Clearance
      Item Specified Condition
      Camshaft No. 1 journal 0.085 mm (0.00335 in.)
      Camshaft other journals 0.09 mm (0.00354 in.)

      Note

      Completely remove the Plastigage after the inspection.

      If the oil clearance is greater than the maximum, replace the camshaft. If necessary, replace the cylinder head sub-assembly.

  6. INSPECT INNER COMPRESSION SPRING

    Tech Tips

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

    Type Compression Spring Shape
    A Straight
    B Tapered
    A01TBLMC01
    *A Type A
    *B Type B
    *1 No. 1 Valve Rocker Arm Sub-assembly
    *2 Valve Spring Retainer
    *3 Compression Spring
    *4 Valve Lash Adjuster Assembly

    1. Type A:


      1. A01TA04

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

        Reference free length (New parts)
        53.88 mm (2.12 in.)
      2. A01TC3J

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

        Maximum deviation
        1.0 mm (0.0394 in.)

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

    2. Type B:


      1. A01TB3L

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

        Reference free length (New parts)
        51.88 mm (2.042 in.) or 51.90 mm (2.043 in.)
      2. A01T8O1C22
        *a Deviation

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

        Maximum deviation
        1.3 mm (0.0512 in.)

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

  7. INSPECT INTAKE VALVE


    1. A01TD1JC15
      *a Overall Length

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

      Standard overall length
      109.34 mm (4.3047 in.)
      Minimum overall length
      108.84 mm (4.2850 in.)

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

    2. A01TAVO

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

      Standard valve stem diameter
      5.470 to 5.485 mm (0.2154 to 0.2159 in.)

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

    3. A01TDCLC03
      *a Margin Thickness

      Using a vernier caliper, measure the intake 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 intake valve.

  8. INSPECT EXHAUST VALVE


    1. A01TAIYC09
      *a Overall Length

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

      Standard overall length
      108.25 mm (4.2618 in.)
      Minimum overall length
      107.75 mm (4.2421 in.)

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

    2. A01TDHA

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

      Standard valve stem diameter
      5.465 to 5.480 mm (0.2152 to 0.2157 in.)

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

    3. A01TAVUC12
      *a Margin Thickness

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

      Standard margin thickness
      1.01 mm (0.0398 in.)
      Minimum margin thickness
      0.5 mm (0.0197 in.)

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

  9. INSPECT VALVE GUIDE BUSH OIL CLEARANCE


    1. A01TB85

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

      Guide bush inside diameter
      5.510 to 5.530 mm (0.2169 to 0.2177 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 greater than the maximum, replace the valve and valve guide bush.