CYLINDER HEAD INSPECTION


  1. INSPECT CYLINDER HEAD SUB-ASSEMBLY


    1. A01EL66E02
      Text in Illustration
      *1 Cylinder Head Lower Side:
      *2 Intake Manifold Side:
      *3 Exhaust Manifold Side:

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

      Maximum Warpage
      Item Specified Condition
      Cylinder head lower 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. A01EIQV

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

      If cracked, replace the cylinder head.

  2. INSPECT COMPRESSION SPRING


    1. A01EJNF

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

      Standard free length
      47.2 to 49.2 mm (1.86 to 1.94 in.)

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

    2. A01EKOIE02
      Text in Illustration
      *1 Deviation

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

      Maximum deviation
      1.0 mm (0.0394 in.)
      Maximum angle
      2°

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

  3. INSPECT INTAKE VALVE


    1. A01EJFB

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

      Standard valve stem diameter
      5.470 mm to 5.485 mm (0.2154 to 0.2159 in.)
    2. A01ELJHE02
      Text in Illustration
      *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
      0.50 mm (0.0197 in.)

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

    3. A01EJA6E02
      Text in Illustration
      *1 Overall Length

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

      Standard overall length
      103.92 mm (4.09 in.)
      Minimum overall length
      103.42 mm (4.07 in.)

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

  4. INSPECT EXHAUST VALVE


    1. A01ELLD

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

      Standard valve stem diameter
      5.465 mm to 5.480 mm (0.2152 to 0.2157 in.)
    2. A01EJ7GE02
      Text in Illustration
      *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
      0.50 mm (0.0197 in.)

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

    3. A01EM5EE02
      Text in Illustration
      *1 Overall Length

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

      Standard overall length
      112.91 mm (4.44 in.)
      Minimum overall length
      112.41 mm (4.43 in.)

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

  5. INSPECT VALVE GUIDE BUSH OIL CLEARANCE


    1. A01ELB5

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

      Standard 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 0.08 mm (0.00315 in.)
      Exhaust 0.10 mm (0.00394 in.)

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

  6. INSPECT INTAKE VALVE SEAT


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

    2. A01EIT4E02
      Text in Illustration
      *1 Width

      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. 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 1.1 and 1.5 mm (0.0433 and 0.0591 in.).

        If not, correct the valve seat.

      2. 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.

  7. INSPECT EXHAUST VALVE SEAT


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

    2. A01EMEKE02
      Text in Illustration
      *1 Width

      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. 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 1.1 and 1.5 mm (0.0433 and 0.0591 in.).

        If not, correct the valve seat.

      2. 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.

  8. INSPECT CAMSHAFT OIL CLEARANCE

    Note

    Do not turn the camshafts.


    1. Clean the bearing caps, camshaft housing and camshaft journals.

    2. Place the camshafts on the camshaft housing.

    3. A01EL1ME02
      Text in Illustration
      *1 Plastigage

      Lay a strip of Plastigage across each of the camshaft journals.

    4. Install the camshaft bearing caps Click here.

    5. Install the camshaft housing sub-assembly Click here.

    6. Remove the camshaft bearing caps Click here.

    7. A01EJY1E02
      Text in Illustration
      *1 Plastigage
      *2 No. 1 Journal
      *3 Other Journal

      Measure the Plastigage at its widest point.

      Standard Oil Clearance
      Item Specified Condition
      Intake No. 1 journal 0.035 to 0.072 mm (0.00137 to 0.00283 in.)
      Exhaust No. 1 journal 0.049 to 0.086 mm (0.00193 to 0.00339 in.)
      Other journal 0.025 to 0.062 mm (0.000984 to 0.00244 in.)
      Maximum Oil Clearance
      Item Specified Condition
      Intake No. 1 journal 0.085 mm (0.00335 in.)
      Exhaust No. 1 journal 0.095 mm (0.00374 in.)
      Other journal 0.085 mm (0.00335 in.)

      If the oil clearance is more than the maximum, replace the camshaft. If necessary, replace the camshaft housing.

  9. INSPECT CAMSHAFT THRUST CLEARANCE


    1. Inspect the intake camshaft.


      1. Install the intake camshaft.

      2. A01EL49

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

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

    2. Inspect the intake and exhaust camshafts.


      1. Install the intake and exhaust camshafts.

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

        Standard thrust clearance
        0.060 to 0.155 mm (0.00236 to 0.00610 in.)
        Maximum thrust clearance
        0.170 mm (0.00669 in.)

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