INSPECT CAMSHAFT OIL CLEARANCE

INSPECT CAMSHAFT THRUST CLEARANCE

INSPECT COMPRESSION SPRING

INSPECT INTAKE VALVE

INSPECT EXHAUST VALVE

INSPECT VALVE GUIDE BUSH OIL CLEARANCE

INSPECT INTAKE VALVE SEAT

INSPECT EXHAUST VALVE SEAT

INSPECT CYLINDER HEAD SUB-ASSEMBLY

Clean the bearing caps, camshaft housing and camshaft journals.

Place the camshafts on the camshaft housing.

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

Install the camshaft bearing caps ().

• NOTICE:

• Do not turn the camshaft.

Install the camshaft housing ().

• NOTICE:

• Do not turn the camshaft.

Remove the camshaft bearing caps ().

Measure the Plastigage at its widest point.

• Standard Oil Clearance:

• Item	Specified Condition
  No. 1 journal	0.030 to 0.065 mm (0.00118 to 0.00256 in.)
  Other journals	0.025 to 0.062 mm (0.000984 to 0.00244 in.)

• Maximum Oil Clearance:

• Item	Specified Condition
  No. 1 journal	0.10 mm (0.00394 in.)
  Other journals	0.09 mm (0.00354 in.)

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

Install the camshafts ().

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

• Standard thrust clearance:
• 0.08 to 0.135 mm (0.00315 to 0.00531 in.)

• Maximum thrust clearance:
• 0.15 mm (0.00591 in.)

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

Perform the inspection above for each camshaft.

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

• Standard free length:
• 51.59 mm (2.03 in.)

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

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

• Maximum deviation:
• 1.0 mm (0.0394 in.)

• Maximum angle (reference):
• 2°

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

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.)

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

• Standard margin thickness:
• 1.25 mm (0.0492 in.)

• Minimum margin thickness:
• 0.50 mm (0.0197 in.)

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

Using a vernier caliper, measure the valve overall length.

• Standard overall length:
• 105.85 mm (4.17 in.)

• Minimum overall length:
• 105.35 mm (4.15 in.)

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

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.)

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

• Standard margin thickness:
• 1.4 mm (0.0551 in.)

• Minimum margin thickness:
• 0.50 mm (0.0197 in.)

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

Using a vernier caliper, measure the valve overall length.

• Standard overall length:
• 110.40 mm (4.35 in.)

• Minimum overall length:
• 109.90 mm (4.33 in.)

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

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.)

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.

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

Lightly press the valve face against the intake valve seat.

• HINT:

• Do not rotate the valve while pressing the valve.

Check the valve face and intake valve seat.

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

Lightly press the valve face against the exhaust valve seat.

• HINT:

• Do not rotate the valve while pressing the valve.

Check the valve face and exhaust valve seat.

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

• Standard Warpage:

• Item	Specified Condition
  Cylinder block side	0.05 mm (0.00197 in.)
  Intake manifold side	0.08 mm (0.00315 in.)
  Exhaust manifold side	0.05 mm (0.00197 in.)

• Maximum warpage:
• 0.10 mm (0.00394 in.)

If the warpage is more than the maximum, replace the cylinder head sub-assembly.

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

If cracked, replace the cylinder head sub-assembly.