CYLINDER HEAD INSPECTION

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PROCEDURE

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   INSPECT CYLINDER HEAD SUB-ASSEMBLY

   
   
   1. 

      *a	Cylinder Head Lower Side	*b	Intake Manifold Side
      *c	Exhaust Manifold Side	-	-

      Using a precision straightedge and feeler gauge, measure the warpage of the surfaces that contact the cylinder block and manifolds.

      Maximum warpage
      0.05 mm (0.00197 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 head surface for cracks.

      If cracked, replace the cylinder head sub-assembly.

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   INSPECT INNER COMPRESSION SPRING

   
   
   1. 

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

      Standard free length
      52.13 mm (2.05 in.)

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

   2. 

      *a	Deviation
      *b	35 mm (1.38 in.)

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

      Maximum deviation
      1.3 mm (0.0512 in.)

      Maximum angle
      2°

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

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   INSPECT INTAKE VALVE

   
   

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

      Standard overall length
      106.26 mm (4.18 in.)

      Minimum overall length
      105.96 mm (4.17 in.)

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

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

      Standard valve stem diameter
      5.470 to 5.485 mm (0.215 to 0.216 in.)

   3. 

      *a	Margin Thickness

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

      Standard margin thickness
      1.05 to 1.45 mm (0.0413 to 0.0571 in.)

      Minimum margin thickness
      0.50 mm (0.0197 in.)

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

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   INSPECT EXHAUST VALVE

   
   

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

      Standard overall length
      106.74 mm (4.20 in.)

      Minimum overall length
      106.44 mm (4.19 in.)

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

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

      Standard valve stem diameter
      5.465 to 5.480 mm (0.215 to 0.216 in.)

   3. 

      *a	Margin Thickness

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

      Standard margin thickness
      1.2 to 1.6 mm (0.0472 to 0.0630 in.)

      Minimum margin thickness
      0.50 mm (0.0197 in.)

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

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   INSPECT VALVE SEAT

   
   

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

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

      Tip:

      Do not rotate the valve while pressing the valve against the valve seat.

   3. 

      *a

      Width

      Check the valve face and valve seat by using the following procedure.

      
      

      1. Check that Prussian blue appears around the entire valve face. If not, replace the valve.

      2. Check that Prussian blue appears around the entire valve seat. If so, the guide and valve face are concentric. If not, resurface the valve seat.

      3. Check that the valve seat contacts the middle of the valve face with the width between 1.1 and 1.4 mm (0.0433 and 0.0551 in.).

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   INSPECT CAMSHAFT THRUST CLEARANCE

   
   
   1. 

      Install the camshafts.

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

      Standard thrust clearance
      0.10 to 0.24 mm (0.00394 to 0.00945 in.)

      Maximum thrust clearance
      0.26 mm (0.0102 in.)

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

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   INSPECT CAMSHAFT OIL CLEARANCE

   
   

   1. Clean the camshaft bearing caps and camshaft journals.

   2. Place the camshafts on the cylinder head sub-assembly.

   3. 

      *a	Plastigage

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

   4. Install the camshaft bearing caps.

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      Note:

      Do not turn the camshafts.

   5. Remove the camshaft bearing caps.

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   6. 

      *a	Plastigage

      Measure the Plastigage at its widest point.

      Standard Oil Clearance
      Item Specified Condition No. 1 journal 0.035 to 0.072 mm (0.00138 to 0.00283 in.) Other journals 0.025 to 0.062 mm (0.000984 to 0.00244 in.)

      Maximum oil clearance
      0.08 mm (0.00315 in.)

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

   7. Completely remove the Plastigage.

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   INSPECT VALVE GUIDE BUSH OIL CLEARANCE

   
   
   1. 

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

      Standard 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 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 (0.00397 in.)

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