Cylinder Head: Inspection

WARNING: This page is about a different car, the 2008 Lexus IS F. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT CYLINDER HEAD SUB-ASSEMBLY

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

Standard Warpage

CYLINDER HEAD WARPAGE SPECIFICATION

Item	Specified Condition
Cylinder head lower side	0.05 mm (0.00197 in.)
Intake side	0.08 mm (0 00315 in.)
Exhaust side	0.05 mm (0 00197 in.)

Maximum warpage:

0.10 mm (0.00394 in.)

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

Fig 1: Measuring Warpage Of Contact Surfaces Of Cylinder Block And Manifold

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Fig 2: Checking Intake Ports, Exhaust Ports And Cylinder Surface For Cracks

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT INTAKE VALVE
1. Using a micrometer, measure the diameter of the valve stem
  Standard valve stem diameter:
  
  5.470 to 5.485 mm (0.215 to 0.216 in.)
  
  Fig 3: Measuring Diameter Of Valve Stem
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. 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
  
  Fig 4: Identifying Valve Head Margin Thickness
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Using a vernier caliper, measure the valve's 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
  
  Fig 5: Identifying Valve Overall Length
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT EXHAUST VALVE
1. Using a micrometer, measure the diameter of the valve stem
  Standard valve stem diameter:
  
  5.465 to 5.480 mm (0.215 to 0.216 in.)
  
  Fig 6: Measuring Diameter Of Valve Stem
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. 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
  
  Fig 7: Identifying Valve Head Margin Thickness
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Using a vernier caliper, measure the valve's 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
  
  Fig 8: Identifying Valve Overall Length
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT INTAKE VALVE SEAT
1. Apply a light coat of Prussian blue to the valve face.
2. Lightly press the valve face against the valve seat.
  HINT.
  
  Do not rotate the valve while pressing the valve.
3. Check the valve face and valve seat.
  1. Check that the valve seat contacts the middle of the valve face with the width between 1.1 and 1.5 mm (0 0433 and 0.0591 in.).
    If not, correct the valve seat.
  2. Check that the contact surfaces of the valve seat and valve face are even around the entire valve seat
    If not, correct the valve seat (See REPAIR )
    
    Fig 9: Identifying Intake Valve Seat Width
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT EXHAUST VALVE SEAT
1. Apply a light coat of Prussian blue to the valve face.
2. Lightly press the valve face against the valve seat.
3. Check the valve face and valve seat.
  1. Check that the valve seat contacts the middle of the valve face with the width between 1.3 and 1.7 mm (0.0512 and 0.0669 in.).
    If not, correct the valve seat.
  2. Check that the contact surface of the valve seat and valve face are even around the entire valve seat.
    If not, correct the valve seat (See REPAIR )
    
    Fig 10: Identifying Exhaust Valve Seat Width
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT INNER COMPRESSION SPRING

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

Standard Free Length

INNER COMPRESSION SPRING FREE LENGTH SPECIFICATION

Item	Standard Condition
Intake side	47.86 mm (1.88 in.)
Exhaust side	47 24 mm (1.86 in.)

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

Fig 11: Measuring Free Length Of Inner Compression Spring

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

1.0 mm (0.0394 in.)

Maximum angle (reference):

2°

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

Fig 12: Measuring Deviation Of Inner Compression Spring
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT VALVE GUIDE BUSH OIL CLEARANCE

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

Fig 13: Measuring Inside Diameter Of Guide Bush

Standard Oil Clearance

OIL CLEARANCE SPECIFICATION

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

OIL CLEARANCE SPECIFICATION

Item	Specified Condition
Intake	0.08 mm (0.00315 in.)
Exhaust	0.10 mm (0.00394 in.)

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

INSPECT CAMSHAFT THRUST CLEARANCE
1. Inspect the bank 1 camshafts
  1. Install the bank 1 camshafts
  2. Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth
    Standard thrust clearance:
    
    0.08 to 0.14 mm (0.00315 to 0.00551 in.)
    
    Maximum thrust clearance:
    
    0.15 mm (0.00591 in.)
    
    If the thrust clearance is greater than the maximum, replace the cylinder head. If the camshaft thrust surface is damaged, replace the camshaft.
    
    Fig 14: Measuring Camshaft Thrust Clearance (Bank 1)
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Inspect the bank 2 camshafts.
  1. Install the bank 2 camshafts.
  2. Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth
    Standard thrust clearance:
    
    0.08 to 0.14 mm (0.00315 to 0.00551 in.)
    
    Maximum thrust clearance:
    
    0.15 mm (0.00591 in.)
    
    If the thrust clearance is greater than the maximum, replace the cylinder head. If the camshaft thrust surface is damaged, replace the camshaft
    
    Fig 15: Measuring Camshaft Thrust Clearance (Bank 2)
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002