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.

      A01D451C03
      *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. A01D42C

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

      If cracked, replace the cylinder head sub-assembly.

  3. INSPECT VALVE SEATS


    1. A01D66XC09
      *a Width

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

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

    3. Check the valve face and valve seat according to the following procedure:


      1. If Prussian blue appears 360° around the valve face, the valve face is concentric. If not, replace the valve.

      2. If Prussian blue appears 360° around the valve seat, the guide and valve face are concentric. If not, resurface the valve seat.

      3. Check that the valve seat contact is in the middle of the valve face with the valve seat width between 1.0 and 1.4 mm (Intake side (0.0394 and 0.0551 in.)).

      4. Check that the valve seat contact is in the middle of the valve face with the valve seat width between 1.0 and 1.4 mm (Exhaust side (0.0394 and 0.0551 in.)).

  4. INSPECT CAMSHAFT THRUST CLEARANCE


    1. Install the camshafts.

      Click here

    2. A01D4DD

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

      Standard Thrust Clearance
      Item Specified Condition
      Intake 0.06 to 0.2 mm (0.00236 to 0.00787 in.)
      Exhaust 0.06 to 0.2 mm (0.00236 to 0.00787 in.)
      Maximum Thrust Clearance
      Item Specified Condition
      Intake 0.215 mm (0.00846 in.)
      Exhaust 0.215 mm (0.00846 in.)

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

  5. INSPECT CAMSHAFT OIL CLEARANCE


    1. Clean the camshaft bearing caps and camshaft journals.

    2. Place the camshafts on the camshaft housing sub-assembly.

    3. A01D686C05
      *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. A01D4GLC05
      *a Plastigage

      Measure the Plastigage at its widest point.

      Standard Oil Clearance
      Item Specified Condition
      No. 1 Camshaft journal 0.030 to 0.067 mm (0.00118 to 0.00264 in.)
      Other camshaft journals 0.030 to 0.067 mm (0.00118 to 0.00264 in.)
      Maximum Oil Clearance
      Item Specified Condition
      No. 1 Camshaft journal 0.08 mm (0.00315 in.)
      Other camshaft journals 0.08 mm (0.00315 in.)

      Note

      Completely remove the Plastigage after the inspection.

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

  6. INSPECT 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 Taper
    A01D46CC01
    *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. A01D3RW

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

        Standard free length
        51.19 mm (2.0154 in.)

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

      2. A01D3W8C01
        *a Deviation

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

        Maximum deviation
        1.8 mm (0.0709 in.)

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

    2. Type B:


      1. A01D3YP

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

        Standard free length
        57.49 mm (2.2634 in.)

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

      2. A01D64UC02
        *a Deviation

        Using a steel square and feeler gauge, measure the deviation of the compression spring as shown in the illustration.

        Maximum deviation
        1.75 mm (0.0689 in.)
        Maximum angle
        2°

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

  7. INSPECT INTAKE VALVE


    1. A01D4ZC

      Using a gasket scraper, scrape off any carbon on the intake valve head.

    2. Using a wire brush, thoroughly clean the valve.

    3. A01D5VLC12
      *a Overall Length

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

      Standard overall length
      103.35 mm (4.0689 in.)
      Minimum overall length
      102.85 mm (4.0492 in.)

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

    4. A01D4JK

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

      Standard valve stem diameter
      5.470 to 5.485 mm (0.21535 to 0.21594 in.)

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

    5. A01D534C04
      *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. A01D4ZC

      Using a gasket scraper, scrape off any carbon on the exhaust valve head.

    2. Using a wire brush, thoroughly clean the valve.

    3. A01D6FLC11
      *a Overall Length

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

      Standard overall length
      104.5 mm (4.114 in.)
      Minimum overall length
      104.0mm (4.0945 in.)

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

    4. A01D4BM

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

      Standard valve stem diameter
      5.465 to 5.480 mm (0.21516 to 0.21575 in.)

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

    5. A01D4V8C15
      *a Margin Thickness

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

      Standard margin thickness
      1.15 mm (0.0453 in.)
      Minimum margin thickness
      0.65 mm (0.0256 in.)

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

  9. INSPECT VALVE GUIDE BUSH OIL CLEARANCE


    1. A01D4E6

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

      Standard bushing inside diameter
      5.51 to 5.53 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 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 (0.00315in.)
      Exhaust 0.085 mm (0.00335in.)

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