CYLINDER HEAD INSPECTION


  1. INSPECT CYLINDER HEAD SUB-ASSEMBLY


    1. A01NFC7E08

      Using a precision straightedge and feeler gauge, measure the warpage of the contact surface of the cylinder block sub-assembly and manifolds.

      Standard Warpage
      Item Warpage
      Cylinder head lower 0.05 mm (0.00197 in.)
      Intake 0.08 mm (0.00315 in.)
      Exhaust 0.08 mm (0.00315 in.)
      Maximum Warpage
      Item Warpage
      Cylinder head lower 0.10 mm (0.00394 in.)
      Intake 0.10 mm (0.00394 in.)
      Exhaust 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. A01NDAF

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

      If cracked, replace the cylinder head sub-assembly.

  3. INSPECT INTAKE VALVE


    1. A01NE7E

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

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

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

    2. A01ND3HE02
      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
      0.5 mm (0.0197 in.)

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

    3. A01NHBIE02
      Text in Illustration
      *1 Overall Length

      Using a vernier caliper, measure the valve overall length.

      Standard overall length
      105.85 mm (4.1673 in.)
      Minimum overall length
      105.35 mm (4.1476 in.)

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

  4. INSPECT EXHAUST VALVE


    1. A01NEYY

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

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

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

    2. A01NGRGE02
      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
      0.5 mm (0.0197 in.)

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

    3. A01NG5EE02
      Text in Illustration
      *1 Overall Length

      Using a vernier caliper, measure the valve overall length.

      Standard overall length
      110.40 mm (4.3464 in.)
      Minimum overall length
      109.90 mm (4.3268 in.)

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

  5. INSPECT INTAKE VALVE SEAT


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

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

    3. A01NEX0E03
      Text in Illustration
      *1 Width

      Check the valve face and valve spring seat by using the following procedure:


      1. If Prussian blue appears around the entire valve face, the valve face is concentric. 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 spring seat.

      3. Check that the valve spring seat contacts in the middle of the valve face with the width between 1.1 and 1.6 mm (0.0433 and 0.0630 in.).

  6. INSPECT EXHAUST VALVE SEAT


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

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

    3. A01NEX0E03
      Text in Illustration
      *1 Width

      Check the valve face and valve spring seat by using the following procedure:


      1. If Prussian blue appears around the entire valve face, the valve face is concentric. 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 spring seat.

      3. Check that the valve spring seat contacts in the middle of the valve face with the width between 1.1 and 1.6 mm (0.0433 and 0.0630 in.).

  7. INSPECT INNER COMPRESSION SPRING

    Tech Tips

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

    A01NH31E01
    Text in Illustration
    *A Type A
    *B Type B
    *1 No. 1 Valve Rocker Arm Sub-assembly
    *2 Valve Spring Retainer
    *3 Inner Compression Spring
    *a Valve Spring Retainer Diameter
    *b No. 1 Valve Rocker Arm Sub-assembly Roller Width
    Type No. 1 Valve Rocker Arm Sub-assembly Roller Width Valve Spring Retainer Diameter Inner Compression Spring Shape
    A 10.7 mm (0.421 in.) 23.4 mm (0.921 in.) Straight
    B 8.0 mm (0.315 in.) 18.9 mm (0.744 in.) Taper

    1. Type A:


      1. A01NELS

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

        Free length
        45.91 mm (1.8075 in.)

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

      2. A01NHC3E02
        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.)

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

    2. Type B:


      1. A01NF2G

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

        Free length
        50.55 mm (1.9902 in.)

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

      2. A01NG5GE10
        Text in Illustration
        *1 Deviation
        *a 40 mm (1.57 in.)

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

        Maximum deviation
        1.4 mm (0.0551 in.)

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

  8. INSPECT VALVE GUIDE BUSH OIL CLEARANCE


    1. A01NFF4

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

      Standard Oil Clearance
      Item Clearance
      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 Clearance
      Intake 0.08 mm (0.00315 in.)
      Exhaust 0.10 mm (0.00394 in.)

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