CYLINDER HEAD > INSPECTION

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1. Remove all carbon on the valves.
   

   CAUTION:

   Wear protective goggles while servicing.

1. Using a straightedge and feeler gauge, measure the warpage of the contact surface indicated in the illustration.
   

   Maximum warpage:

   0.05 mm (0.002 in.)
   

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

2. Using a dye penetrant, check the combustion chamber, intake ports, exhaust ports and cylinder block surface for cracks.
   

1. Install the 2 camshafts.
   

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

   Standard thrust clearance:

   0.100 to 0.225 mm (0.00394 to 0.00886 in.)
   

   Maximum thrust clearance:

   0.240 mm (0.00944 in.)
   

   If the thrust clearance is greater than the maximum, replace the cylinder head. If damage is found on the camshaft thrust surfaces, replace the camshaft.
   

1. Clean the 7 bearing caps and camshaft journals.
   

2. Place the camshafts on the cylinder head.
   

3. Lay a strip of Plastigage on the journal in the axial direction.
   

   Text in Illustration 

   *1	Plastigage

4. Place the No. 1 camshaft bearing cap and No. 2 camshaft bearing caps and tighten the bolts to the specified torque in the order shown in the illustration.
   

   Torque:

   No. 1 camshaft bearing cap:

   15 N*m{ 153 kgf*cm , 11 ft.*lbf }

   No. 2 camshaft bearing cap:

   13 N*m{ 127 kgf*cm , 9 ft.*lbf }

5. Remove the 7 bearing caps.
   

6. Measure the Plastigage at its widest point.
   

   Standard Oil Clearance:

   Item	Specified Condition (Intake Side)	Specified Condition (Exhaust Side)
   Camshaft No. 1 journal	0.025 to 0.061 mm (0.00098 to 0.00240 in.)	0.037 to 0.073 mm (0.00146 to 0.00287 in.)
   Camshaft other journal	0.035 to 0.072 mm (0.00138 to 0.00283 in.)	0.035 to 0.072 mm (0.00138 to 0.00283 in.)

   Maximum Oil Clearance:

   Item	Specified Condition (Intake Side)	Specified Condition (Exhaust Side)
   Camshaft No. 1 journal	0.09 mm (0.00354 in.)	0.10 mm (0.00393 in.)
   Camshaft other journal	0.10 mm (0.00393 in.)	0.10 mm (0.00393 in.)

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

1. Using a straightedge and feeler gauge, measure the deviation of the inner compression spring.
   

   Maximum deviation:

   1.5 mm (0.059 in.)
   

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

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

   Free length:

   51.63 mm (2.0327 in.)
   

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

1. Using a vernier caliper, check the valve overall length.
   

   Standard overall length:

   88.39 mm (3.4799 in.)
   

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

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

   Valve stem end diameter:

   3.9 to 4.5 mm (0.154 to 0.177 in.)
   

   If the diameter is not as specified, replace the intake valve.
   

3. Using a vernier caliper, check the valve head margin thickness.
   

   Standard margin thickness:

   1.05 to 1.45 mm (0.0413 to 0.0571 in.)
   

   Minimum margin thickness:

   0.7 mm (0.028 in.)
   

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

4. Using a vernier caliper, check the valve head diameter.
   

   Standard diameter:

   27.35 to 27.65 mm (1.0768 to 1.0886 in.)
   

   If the diameter is not as specified, replace the intake valve.
   

1. Using a vernier caliper, check the valve overall length.
   

   Standard overall length:

   89.11 mm (3.5083 in.)
   

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

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

   Valve stem end diameter:

   3.9 to 4.5 mm (0.154 to 0.177 in.)
   

   If the diameter is not as specified, replace the exhaust valve.
   

3. Using a vernier caliper, check the valve head margin thickness.
   

   Standard margin thickness:

   1.10 to 1.50 mm (0.0433 to 0.0591 in.)
   

   Minimum margin thickness:

   0.7 mm (0.028 in.)
   

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

4. Using a vernier caliper, check the valve head diameter.
   

   Standard diameter:

   23.45 to 23.75 mm (0.9232 to 0.9350 in.)
   

   If the diameter is not as specified, replace the exhaust valve.
   

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

   Intake valve guide bush inside diameter:

   5.01 to 5.03 mm (0.19724 to 0.19803 in.)
   

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

2. Subtract the valve stem diameter measurement from the guide bush inside diameter measurement to calculate the oil clearance.
   

   Intake valve stem diameter:

   4.970 to 4.985 mm (0.19567 to 0.19626 in.)
   

   Standard oil clearance:

   0.025 to 0.060 mm (0.00098 to 0.00236 in.)
   

   Maximum oil clearance:

   0.08 mm (0.00315 in.)
   

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

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

   Exhaust valve guide bush inside diameter:

   5.01 to 5.03 mm (0.19724 to 0.19803 in.)
   

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

2. Subtract the valve stem diameter measurement from the guide bush inside diameter measurement to calculate the oil clearance.
   

   Exhaust valve stem diameter:

   4.965 to 4.980 mm (0.19547 to 0.19606 in.)
   

   Standard oil clearance:

   0.030 to 0.065 mm (0.00118 to 0.00256 in.)
   

   Maximum oil clearance:

   0.10 mm (0.00394 in.)
   

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