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 sub-assembly contacts the cylinder block sub-assembly and each manifold.

      A018L9TC12
      *a Bottom Side *b Intake Manifold Side
      *c Exhaust Manifold Side - -
      Maximum Warpage
      Item Specified Condition
      Bottom 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 more than the maximum, replace the cylinder head sub-assembly.

    2. A018MHP

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

      If cracks are found, replace the cylinder head sub-assembly.

  2. INSPECT COMPRESSION SPRING


    1. A018JF6

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

      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 compression spring.

    2. A018LFAC19
      *a Deviation

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

      Maximum Deviation
      1.0 mm (0.0394 in.)
      Maximum Angle
      2°

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

  3. INSPECT INTAKE VALVE


    1. A018JVD

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

      Standard Valve Stem Diameter
      5.470 to 5.485 mm (0.21535 to 0.21594 in.)

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

    2. A018KAEC14
      *a 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. A018HJHC12
      *a Overall Length

      Using a vernier caliper, measure the overall length of the intake 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. A018JDD

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

      Standard Valve Stem Diameter
      5.465 to 5.480 mm (0.21516 to 0.21575 in.)

      If the result is not as specified, check the oil clearance.

    2. A018JD1C16
      *a 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. A018H6FC12
      *a Overall Length

      Using a vernier caliper, measure the valve overall length.

      Standard Overall Length
      112.91 mm (4.45 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. A018IHQ

      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 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. A018KQAC16
      *a Width

      Lightly press the valve face against the intake valve seat.

      Tech Tips

      Do not rotate the intake valve while pressing it.

    3. Check the valve face and intake valve seat by using the following procedure:


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

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

      3. Check that the intake valve seat contacts the middle of the valve face with the width between 1.1 and 1.5 mm (0.0433 and 0.0591 in.).

  7. INSPECT EXHAUST VALVE SEAT


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

    2. A018ISIC12
      *a Width

      Lightly press the valve face against the exhaust valve seat.

      Tech Tips

      Do not rotate the exhaust valve while pressing it.

    3. Check the valve face and exhaust valve seat by using the following procedure:


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

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

      3. Check that the exhaust valve seat contacts the middle of the valve face with the width between 1.1 and 1.5 mm (0.0433 and 0.0591 in.).

  8. INSPECT CAMSHAFT OIL CLEARANCE


    1. Clean the No. 1 camshaft bearing cap, No. 2 camshaft bearing cap, 3 No. 3 camshaft bearing caps, camshaft housing sub-assembly and camshaft journals.

    2. Place the camshaft and No. 2 camshaft on the camshaft housing sub-assembly.

    3. A018L7VC09
      *a Plastigage

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

    4. Install the No. 1 camshaft bearing cap, No. 2 camshaft bearing cap and 3 No. 3 camshaft bearing caps.

      Click here

      Note

      Do not turn the camshafts.

    5. Install the camshaft housing sub-assembly.

      Click here

    6. Remove the No. 1 camshaft bearing cap, No. 2 camshaft bearing cap and 3 No. 3 camshaft bearing caps.

      Click here

    7. A018JIXC10
      *a Plastigage
      *b No. 1 Journal
      *c Other Journal

      Measure the Plastigage at its widest point.

      Standard Oil Clearance
      Item Specified Condition
      Intake No. 1 journal 0.035 to 0.072 mm (0.00138 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.)

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

  9. INSPECT CAMSHAFT THRUST CLEARANCE


    1. Clean the No. 1 camshaft bearing cap, No. 2 camshaft bearing cap, 3 No. 3 camshaft bearing caps, camshaft housing sub-assembly and camshaft journals.

    2. Place the camshaft and No. 2 camshaft on the camshaft housing sub-assembly.

    3. Install the No. 1 camshaft bearing cap, No. 2 camshaft bearing cap and 3 No. 3 camshaft bearing caps.

      Click here

    4. Install the camshaft housing sub-assembly.

      Click here

    5. A018JDF

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

      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 sub-assembly. If the thrust surface is damaged, replace the camshaft.