CYLINDER HEAD INSPECTION

  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.

      A011V42E05
      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.)
      Text in Illustration
      *a Cylinder Head Lower Side
      *b Intake Manifold Side
      *c Exhaust Manifold Side

      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 surface for cracks.

      If cracked, replace the cylinder head.

      A011RMH

  2. INSPECT COMPRESSION SPRING

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

      A011SBD
      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. Using a steel square, measure the deviation of the inner compression spring.

      A011U8VE05
      Maximum deviation
      1.0 mm (0.0394 in.)
      Maximum angle
      2°
      Text in Illustration
      *a Deviation

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

  3. INSPECT INTAKE VALVE

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

      A011R4D
      Standard valve stem diameter
      5.470 mm to 5.485 mm (0.21535 to 0.21594 in.)

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

      A011R11E05
      Standard margin thickness
      1.0 mm (0.0394 in.)
      Minimum margin thickness
      0.50 mm (0.0197 in.)
      Text in Illustration
      *a Margin Thickness

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

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

      A011UDIE04
      Standard overall length
      103.92 mm (4.09 in.)
      Minimum overall length
      103.42 mm (4.07 in.)
      Text in Illustration
      *a Overall Length

      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.

      A011U0N
      Standard valve stem diameter
      5.465 mm to 5.480 mm (0.21516 to 0.21575 in.)

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

      A011S2FE05
      Standard margin thickness
      1.0 mm (0.0394 in.)
      Minimum margin thickness
      0.50 mm (0.0197 in.)
      Text in Illustration
      *a Margin Thickness

      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.

      A011UBME04
      Standard overall length
      112.91 mm (4.44 in.)
      Minimum overall length
      112.41 mm (4.43 in.)
      Text in Illustration
      *a Overall Length

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

  5. INSPECT VALVE GUIDE BUSH OIL CLEARANCE

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

      A011ULF
      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. Lightly press the valve face against the valve seat.

      A011QT5E05
      Text in Illustration
      *a Width

      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. Lightly press the valve face against the valve seat.

      A011THWE05
      Text in Illustration
      *a Width

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

      A011TNAE04
      Text in Illustration
      *1 Plastigage

    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. Measure the Plastigage at its widest point.

      A011SW6E04
      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.)
      Text in Illustration
      *1 Plastigage
      *2 No. 1 Journal
      *3 Other Journal

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

  9. INSPECT CAMSHAFT THRUST CLEARANCE

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

    2. Place the camshafts on the camshaft housing.

    3. Install the camshaft bearing caps Click here.

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

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

      A011TPN
      Standard Thrust Clearance
      Item Specified Condition
      Intake 0.060 to 0.155 mm (0.00236 to 0.00610 in.)
      Exhaust 0.060 to 0.155 mm (0.00236 to 0.00610 in.)
      Maximum Thrust Clearance
      Item Specified Condition
      Intake 0.170 mm (0.00669 in.)
      Exhaust 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.