CYLINDER HEAD INSPECTION

PROCEDURE

  1. INSPECT CYLINDER HEAD SUB-ASSEMBLY

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

      A284093C07

      *a

      Cylinder Head Lower Side

      *b

      Intake Manifold Side

      *c

      Exhaust Manifold Side

      -

      -

      Maximum Warpage

      Item

      Specified Condition

      Cylinder head lower side

      0.05 mm (0.00197 in.)

      Intake manifold side

      0.10 mm (0.0394 in.)

      Exhaust manifold side

      0.10 mm (0.0394 in.)

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

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

      If cracked, replace the cylinder head sub-assembly.

  2. INSPECT INNER COMPRESSION SPRING

    1. A333833

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

      Standard free length

      47.2 mm (1.86 in.)

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

    2. A335450C03

      *a

      Deviation

      *b

      30 mm (1.18 in.)

      Using a steel square, measure the deviation of the inner compression spring at the position shown in the illustration.

      Maximum deviation

      1.05 mm (0.0413 in.)

      Maximum angle

      2°

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

  3. INSPECT INTAKE VALVE

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

      Standard valve stem diameter

      5.470 to 5.485 mm (0.2151 to 0.2157 in.)

    2. A194993C06

      *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 intake valve.

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

      Standard valve stem diameter

      5.465 to 5.480 mm (0.2153 to 0.2159 in.)

    2. A194996C08

      *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. 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. A194967

      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 valve guide bush.

  6. INSPECT INTAKE VALVE SEAT

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

    2. A194998C08

      *1

      Width

      Lightly press the valve face against the valve seat.

      Tip:

      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. A194999C06

      *1

      Width

      Lightly press the valve face against the valve seat.

      Tip:

      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 THRUST CLEARANCE

    1. Inspect the camshaft and No. 2 camshaft.

      1. Install the camshaft and No. 2 camshaft.

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      2. A194962

        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.