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Inspection [10/2018 - ]: Procedure

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  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, intake manifold and exhaust manifold.
      GTY789913Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *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.)

      HINT: 

      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 head sub-assembly surface for cracks.
      GTY756887Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT: 

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

  2. INSPECT COMPRESSION SPRING 
    1. Intake Side:
      1. Using a vernier caliper, measure the free length of the compression spring.

        Standard Free Length

        58.81 mm (2.32 in.)

        NOTE:

        Compression springs come in 2 different lengths. Make sure all compression springs are the same length when replacing them.

        GTY756890Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      2. Using a steel square, measure the deviation of the compression spring.

        Maximum Deviation (Reference)

        1.0 mm (0.0394 in.)

        HINT: 

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

        GTY788695Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
        *a Deviation
        *b 37 mm (1.46 in.)
    2. Exhaust Side:
      1. Using a vernier caliper, measure the free length of the compression spring.
        GTY756890Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        Standard Free Length

        58.81 mm (2.32 in.)

        NOTE:

        Compression springs come in 2 different lengths. Make sure all compression springs are the same length when replacing them.

      2. Using a steel square, measure the deviation of the compression spring.
        GTY757686Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
        *a Deviation
        *b 37 mm (1.46 in.)

        Maximum Deviation (Reference)

        1.0 mm (0.0394 in.)

        HINT: 

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

  3. INSPECT INTAKE VALVE 
    1. Using a micrometer, measure the diameter of the valve stem.
      GTY756892Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Valve Stem Diameter

      5.470 to 5.485 mm (0.215 to 0.216 in.)

      HINT: 

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

    2. Using a vernier caliper, measure the valve head margin thickness.
      GTY761889Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Margin Thickness

      Standard Margin Thickness

      1.0 mm (0.0394 in.)

      Minimum Margin Thickness

      0.5 mm (0.0197 in.)

      HINT: 

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

    3. Using a vernier caliper, measure the overall length of the intake valve.
      GTY767342Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Overall Length

      Standard Overall Length

      102.45 mm (4.03 in.)

      Minimum Overall Length

      101.95 mm (4.01 in.)

      HINT: 

      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.
      GTY772132Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Valve Stem Diameter

      5.465 to 5.480 mm (0.215 to 0.216 in.)

      HINT: 

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

    2. Using a vernier caliper, measure the valve head margin thickness.
      GTY743223Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Margin Thickness

      Standard Margin Thickness

      1.0 mm (0.0394 in.)

      Minimum Margin Thickness

      0.5 mm (0.0197 in.)

      HINT: 

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

    3. Using a vernier caliper, measure the overall length of the exhaust valve.
      GTY768815Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Overall Length

      Standard Overall Length

      106.4 mm (4.19 in.)

      Minimum Overall Length

      105.9 mm (4.17 in.)

      HINT: 

      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 valve guide bush.
      GTY838215Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Valve Guide Bush Inside Diameter

      5.51 to 5.53 mm (0.217 to 0.218 in.)

    2. Subtract the valve stem diameter measurement from the valve guide bush inside diameter measurement.

      Standard Oil Clearance

      Item Specified Condition
      Intake Side 0.025 to 0.060 mm (0.000984 to 0.00236 in.)
      Exhaust Side 0.030 to 0.065 mm (0.00118 to 0.00256 in.)

      Maximum Oil Clearance

      Item Specified Condition
      Intake Side 0.080 mm (0.00315 in.)
      Exhaust Side 0.10 mm (0.00394 in.)

      HINT: 

      • Oil clearance = Valve guide bush inside - Valve stem diameter
      • 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. Lightly press the valve face against the intake valve seat.
      GTY784780Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Width
      NOTE:

      Do not rotate the 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 intake valve face, the valve face is concentric.

        HINT: 

        If the valve face is not concentric, replace the intake valve.

      2. If Prussian blue appears 360° around the entire intake valve seat, the intake valve seat and valve face are concentric.

        HINT: 

        If the valve face is not concentric, resurface the intake valve seat.

      3. Measure the width of the contact area of the intake valve seat and valve face.

        Standard Width

        1.0 to 1.4 mm (0.0394 to 0.0551 in.)

  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 exhaust valve seat.
      GTY778981Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Width
      NOTE:

      Do not rotate the 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.

        HINT: 

        If the valve face is not concentric, replace the exhaust valve.

      2. If Prussian blue appears 360° around the entire exhaust valve seat, the exhaust valve seat and valve face are concentric.

        HINT: 

        If the valve face is not concentric, resurface the exhaust valve seat.

      3. Measure the width of the contact area of the exhaust valve seat and valve face.

        Standard Width

        1.3 to 1.7 mm (0.0512 to 0.0669 in.)

  8. INSPECT CAMSHAFT THRUST CLEARANCE 
    1. Clean the No. 1 camshaft bearing cap, No. 2 camshaft bearing cap, 2 No. 3 camshaft bearing caps, No. 4 camshaft bearing cap, camshaft housing sub-assembly and camshaft journals.
    2. Place the intake camshaft sub-assembly and exhaust camshaft sub-assembly on the camshaft housing sub-assembly on the cylinder head sub-assembly.
    3. Install the camshaft bearing caps.

      See step  25

    4. Install the camshaft housing sub-assembly.

      See step  26

    5. Using a dial indicator, measure the thrust clearance while moving the intake camshaft sub-assembly and exhaust camshaft sub-assembly back and forth.
      GTY824967Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Thrust Clearance

      Item Specified Condition
      Intake camshaft sub-assembly 0.04 to 0.17 mm (0.00157 to 0.00669 in.)
      Exhaust camshaft sub-assembly 0.04 to 0.17 mm (0.00157 to 0.00669 in.)

      Maximum Thrust Clearance

      Item Specified Condition
      Intake camshaft sub-assembly 0.22 mm (0.00866 in.)
      Exhaust camshaft sub-assembly 0.22 mm (0.00866 in.)

      HINT: 

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

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