CYLINDER HEAD INSPECTION

PROCEDURE

INSPECT CYLINDER HEAD SUB-ASSEMBLY

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

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

Maximum Warpage

Item	Specified Condition
Cylinder head lower 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.)

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 surface for cracks.

If cracked, replace the cylinder head sub-assembly.

INSPECT INNER COMPRESSION SPRING
1. Using a vernier caliper, measure the free length of the inner compression spring.
  
  Standard free length
  
  47.38 mm (1.865 in.)
2. *a Deviation
  
  *b 30 mm (1.18 in.)
  
  Using a steel square, measure the deviation of the inner compression spring.
  
  Maximum deviation
  
  1.05 mm (0.0413 in.)
  
  Maximum angle
  
  2°
  
  If the deviation is more than the maximum, replace the inner compression spring.
INSPECT INTAKE VALVE
1. Using a micrometer, measure the diameter of the valve stem.
  
  Standard valve stem diameter
  
  5.470 to 5.485 mm (0.2154 to 0.2159 in.)
2. *a Margin Thickness
  
  Using a vernier caliper, measure the valve head margin thickness.
  
  Standard margin thickness
  
  1.0 mm (0.0394 in.)
  
  Minimum margin thickness
  
  0.50 mm (0.0197 in.)
  
  If the margin thickness is less than the minimum, replace the intake valve.
3. Using a vernier caliper, measure the overall length of the valve.
  
  Standard overall length
  
  103.92 mm (4.09 in.)
  
  Minimum overall length
  
  103.42 mm (4.07 in.)
  
  If the overall length is less than the minimum, replace the intake valve.
INSPECT EXHAUST VALVE
1. Using a micrometer, measure the diameter of the valve stem.
  
  Standard valve stem diameter
  
  5.465 to 5.480 mm (0.2152 to 0.2157 in.)
2. *a Margin Thickness
  
  Using a vernier caliper, measure the valve head margin thickness.
  
  Standard margin thickness
  
  1.0 mm (0.0394 in.)
  
  Minimum margin thickness
  
  0.50 mm (0.0197 in.)
  
  If the margin thickness is less than the minimum, replace the exhaust valve.
3. Using a vernier caliper, measure the overall length of the valve.
  
  Standard overall length
  
  112.91 mm (4.45 in.)
  
  Minimum overall length
  
  112.41 mm (4.43 in.)
  
  If the overall length is less than the minimum, replace the exhaust valve.

Standard free length
47.38 mm (1.865 in.)

Maximum deviation
1.05 mm (0.0413 in.)

Maximum angle
2°

Standard valve stem diameter
5.470 to 5.485 mm (0.2154 to 0.2159 in.)

Standard margin thickness
1.0 mm (0.0394 in.)

Minimum margin thickness
0.50 mm (0.0197 in.)

Standard overall length
103.92 mm (4.09 in.)

Minimum overall length
103.42 mm (4.07 in.)

Standard valve stem diameter
5.465 to 5.480 mm (0.2152 to 0.2157 in.)

Standard margin thickness
1.0 mm (0.0394 in.)

Minimum margin thickness
0.50 mm (0.0197 in.)

Standard overall length
112.91 mm (4.45 in.)

Minimum overall length
112.41 mm (4.43 in.)

INSPECT VALVE GUIDE BUSH OIL CLEARANCE

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

Standard bush inside diameter

5.510 to 5.530 mm (0.2169 to 0.2177 in.)

Standard bush inside diameter
5.510 to 5.530 mm (0.2169 to 0.2177 in.)

Subtract the valve stem diameter measurement from the 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.

INSPECT INTAKE VALVE SEAT
1. Apply a light coat of Prussian blue to the valve face.
2. *a Width
  
  Lightly press the valve face against the intake valve seat.
  
  Tech Tips
  
  Do not rotate the valve while pressing the valve.
3. Check the valve face and intake valve seat.
  1. Check that the contact surfaces of the intake valve seat and valve face are in the middle area of their respective surfaces, with the width between 1.0 and 1.4 mm (0.0394 and 0.0551 in.).
    
    If not, correct the intake valve seat.
  2. Check that the contact surfaces of the intake valve seat and valve face are even around the entire intake valve seat.
    
    If not, correct the intake valve seat.
INSPECT EXHAUST VALVE SEAT
1. Apply a light coat of Prussian blue to the valve face.
2. *a Width
  
  Lightly press the valve face against the exhaust valve seat.
  
  Tech Tips
  
  Do not rotate the valve while pressing the valve.
3. Check the valve face and exhaust valve seat.
  1. Check that the contact surfaces of the exhaust valve seat and valve face are in the middle area of their respective surfaces, with the width between 1.2 and 1.6 mm (0.0472 and 0.0630 in.).
    
    If not, correct the exhaust valve seat.
  2. Check that the contact surfaces of the exhaust valve seat and valve face are even around the entire exhaust valve seat.
    
    If not, correct the exhaust valve seat.
INSPECT CAMSHAFT THRUST CLEARANCE
1. Inspect the camshaft and No. 2 camshaft.
  1. Install the camshaft and No. 2 camshaft.
    
    Click here
  2. Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.
    
    Standard thrust clearance
    
    0.060 to 0.155 mm (0.00236 to 0.00610 in.)
    
    Maximum thrust clearance
    
    0.170 mm (0.00669 in.)
    
    If the thrust clearance is more than the maximum, replace the camshaft housing sub-assembly. If the thrust surface is damaged, replace the camshaft.

*a	Deviation
*b	30 mm (1.18 in.)