CYLINDER HEAD INSPECTION

PROCEDURE

1. INSPECT CYLINDER HEAD SUB-ASSEMBLY

   
   

   1. Inspect the flatness.

      
      

      1. Using a precision straightedge and feeler gauge, measure the warpage on the cylinder block side and the intake and exhaust manifold sides.

         

         Text in Illustration

         *a	Cylinder Block Side	*b	Exhaust Manifold Side
         *c	Intake Manifold Side	-	-

         Maximum Warpage
         Surface Specified Condition Cylinder block side 0.08 mm (0.0032 in.) Intake manifold side 0.20 mm (0.0079 in.) Exhaust manifold side 0.20 mm (0.0079 in.)

         If the warpage is greater than the maximum, replace the cylinder head.

   2. 

      Inspect for cracks.

      
      

      1. Using a dye penetrant, check the combustion chambers, intake ports, exhaust ports and contact surface of the cylinder block for cracks.

         If cracked, replace the cylinder head.

2. INSPECT VALVE SEAT

   
   
   1. 

      Text in Illustration

      *a

      Width

      Apply a light coat of Prussian blue to each valve face.

   2. Gently push the valve seat with the valve installed onto the cylinder head.

      Note

      Do not rotate the valve.

   3. Remove the valve from the cylinder head.

      
      

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

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

      3. Check that the seat contact is in the middle of the valve face with the following width.

3. INSPECT CAMSHAFT OIL CLEARANCE

   
   
   1. 

      Text in Illustration

      *1	Plastigage

      Clean the camshaft and camshaft bearing cap.

   2. Set the camshaft to the cylinder head.

   3. Lay a strip of Plastigage across the camshaft journal.

      Note

      Do not turn the camshaft when measuring.

   4. Install the bearing cap.

   5. Remove the bearing cap.

   6. 

      Text in Illustration

      *1	Plastigage

      Measure the Plastigage at its widest point.

      Standard oil clearance
      0.037 to 0.073 mm (0.0015 to 0.0029 in.)

      Maximum oil clearance
      0.10 mm (0.0039 in.)

      Note

      Completely remove the Plastigage.

      If the clearance is greater than the maximum, replace the cylinder head.

4. INSPECT CAMSHAFT THRUST CLEARANCE

   
   

   1. Set the camshaft to the cylinder head, and then install the camshaft bearing cap.

   2. Install the camshaft timing sprocket onto the camshaft.

   3. 

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

      Standard thrust clearance
      0.040 to 0.090 mm (0.0016 to 0.0035 in.)

      Maximum thrust clearance
      0.25 mm (0.0098 in.)

      If the thrust clearance is greater than the maximum, replace the cylinder head sub-assembly or camshaft.

5. INSPECT INTAKE VALVE

   
   
   1. 

      Text in Illustration

      *a	Overall Length

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

      Standard overall length
      99.69 to 100.29 mm (3.9248 to 3.9484 in.)

      Minimum overall length
      99.19 mm (3.9051 in.)

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

   2. 

      Text in Illustration

      *a	Valve Stem

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

      Valve stem diameter
      5.970 to 5.985 mm (0.2350 to 0.2356 in.)

   3. 

      Text in Illustration

      *a	Margin Thickness

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

      Standard margin thickness
      1.2 mm (0.047 in.)

      Minimum margin thickness
      0.6 mm (0.024 in.)

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

6. INSPECT EXHAUST VALVE

   
   
   1. 

      Text in Illustration

      *a	Overall Length

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

      Standard overall length
      99.39 to 99.99 mm (3.9130 to 3.9366 in.)

      Minimum overall length
      98.89 mm (3.8933 in.)

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

   2. 

      Text in Illustration

      *a	Valve Stem

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

      Valve stem diameter
      5.965 to 5.980 mm (0.2348 to 0.2354 in.)

   3. 

      Text in Illustration

      *a	Margin Thickness

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

      Standard margin thickness
      1.5 mm (0.059 in.)

      Minimum margin thickness
      0.7 mm (0.028 in.)

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

7. INSPECT OUTER COMPRESSION SPRING

   
   

   1. 

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

      Free length
      42.17 mm (1.6602 in.)

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

   2. 

      Text in Illustration

      *a

      Deviation

      Using steel squares, measure the deviation of the outer compression spring.

      Maximum deviation
      1.5 mm (0.059 in.)

      If the deviation is greater than the maximum, replace the outer compression spring.

8. INSPECT VALVE GUIDE BUSH OIL CLEARANCE

   
   

   1. 

      Using a caliper gauge, measure the internal diameter of the valve guide bushing.

      Bushing inside diameter
      6.010 to 6.030 mm (0.2366 to 0.2374 in.)

   2. Subtract the valve stem diameter measurement from the internal diameter measurement of the valve guide bushing.

      Standard Oil Clearance
      Guide Bush Specified Condition Intake 0.025 to 0.060 mm (0.0010 to 0.0024 in.) Exhaust 0.003 to 0.065 mm (0.0001 to 0.0026 in.)

      Maximum Oil Clearance
      Guide Bush Specified Condition Intake 0.08 mm (0.0031 in.) Exhaust 0.10 mm (0.0039 in.)

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