CYLINDER HEAD INSPECTION


  1. INSPECT CYLINDER HEAD SUB-ASSEMBLY


    1. A0094F0E02
      Text in Illustration
      *a Cylinder Head Lower Side
      *b Intake Manifold Side
      *c Exhaust Manifold Side

      Using a precision straightedge and feeler gauge, measure the warpage of the surfaces that contact the cylinder block and manifolds.

      Maximum warpage
      0.05 mm (0.00197 in.)

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

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

      If cracked, replace the cylinder head.

  2. INSPECT INNER COMPRESSION SPRING


    1. A0094QS

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

      Standard free length
      48.53 mm (1.91 in.)

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

    2. A0099ZAE03
      Text in Illustration
      *1 Deviation

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

      Maximum deviation
      1.5 mm (0.0591 in.)
      Maximum angle
      2°

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

  3. INSPECT INTAKE VALVE


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

      Standard overall length
      106.26 mm (4.18 in.)
      Minimum overall length
      105.96 mm (4.17 in.)

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

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

      Standard valve stem diameter
      5.470 to 5.485 mm (0.215 to 0.216 in.)
    3. A009B9ME04
      Text in Illustration
      *1 Margin Thickness

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

      Standard margin thickness
      1.05 to 1.45 mm (0.0413 to 0.0571 in.)
      Minimum margin thickness
      0.50 mm (0.0197 in.)

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

  4. INSPECT EXHAUST VALVE


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

      Standard overall length
      106.74 mm (4.20 in.)
      Minimum overall length
      106.44 mm (4.19 in.)

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

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

      Standard valve stem diameter
      5.465 to 5.480 mm (0.215 to 0.216 in.)
    3. A0098KXE02
      Text in Illustration
      *1 Margin Thickness

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

      Standard margin thickness
      1.2 to 1.6 mm (0.0472 to 0.0630 in.)
      Minimum margin thickness
      0.50 mm (0.0197 in.)

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

  5. INSPECT VALVE SEAT


    1. 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 against the valve seat.

    3. A0099T2E02
      Text in Illustration
      *1 Width

      Check the valve face and valve seat by using the following procedure.


      1. Check that Prussian blue appears around the entire valve face. If not, replace the valve.

      2. If Prussian blue appears around the entire valve seat, the guide and valve face are concentric. If not, resurface the valve seat.

      3. Check that the valve seat contacts the middle of the valve face with the width between 1.1 and 1.4 mm (0.0433 and 0.0551 in.).

  6. INSPECT CAMSHAFT THRUST CLEARANCE


    1. A009C4T

      Install the camshafts Click here.

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

      Standard thrust clearance
      0.10 to 0.24 mm (0.00394 to 0.00945 in.)
      Maximum thrust clearance
      0.26 mm (0.0102 in.)

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

  7. INSPECT CAMSHAFT OIL CLEARANCE


    1. Clean the bearing caps and camshaft journals.

    2. Place the camshafts on the cylinder head.

    3. A0098IJE02
      Text in Illustration
      *1 Plastigage

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

    4. Install the bearing caps Click here.

      Note

      Do not turn the camshafts.

    5. Remove the bearing caps Click here.

    6. A0096Q9E02
      Text in Illustration
      *1 Plastigage

      Measure the Plastigage at its widest point.

      Standard Oil Clearance
      Item Specified Condition
      No. 1 journal 0.035 to 0.072 mm (0.00138 to 0.00283 in.)
      Other journals 0.025 to 0.062 mm (0.000984 to 0.00244 in.)
      Maximum oil clearance
      0.08 mm (0.00315 in.)

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

    7. Completely remove the Plastigage.

  8. INSPECT VALVE GUIDE BUSH OIL CLEARANCE


    1. A0094X1

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

      Standard bush inside diameter
      5.51 to 5.53 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 0.08 mm (0.00315 in.)
      Exhaust 0.10 mm (0.00397 in.)

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