Cylinder Head: Inspection: Inspection

WARNING: This page is about a different variant/trim than selected.

INSPECT CYLINDER HEAD SUB-ASSEMBLY

Using a precision straight edge and feeler gauge, measure the warpage of the contact surface of the cylinder block sub-assembly and manifolds.

Fig 1: Identifying Warpage Of Contact Surface Of Cylinder Block And Manifolds

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard warpage

Item	Warpage
Cylinder head lower	0.05 mm (0.0020 in.)
Intake	0.08 mm (0.0031 in.)
Exhaust	0.08 mm (0.0031 in.)

Maximum warpage

Item	Warpage
Cylinder head lower	0.10 mm (0.0039 in.)
Intake	0.10 mm (0.0039 in.)
Exhaust	0.10 mm (0.0039 in.)

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

INSPECT CYLINDER HEAD FOR CRACKS
1. Using a dye penetrant, check the intake ports, exhaust ports and cylinder surface for cracks.
  
  Fig 2: Identifying Checking Intake Ports, Exhaust Ports And Cylinder Surface For Cracks
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  If cracked, replace the cylinder head sub-assembly.
INSPECT INTAKE VALVE
1. Using a micrometer, measure the diameter of the valve stem.
  
  Fig 3: Identifying Diameter Of Valve Stem Component
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Valve stem diameter
  
  5.470 to 5.485 mm (0.2154 to 0.2159 in.)
  
  If the valve stem is not as specified, check the oil clearance.
2. Using vernier calipers, measure the valve head margin thickness.
  
  Fig 4: Identifying Valve Head Component Margin Thickness
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Standard margin thickness
  
  1.0 mm (0.039 in.)
  
  Minimum margin thickness
  
  0.5 mm (0.0197 in.)
  
  If the margin thickness is less than the minimum, replace the intake valve.
3. Using vernier calipers, measure the valve's overall length.
  
  Fig 5: Identifying Valve Component Overall Length
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Standard overall length
  
  105.85 mm (4.1673 in.)
  
  Minimum overall length
  
  105.35 mm (4.1476 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.
  
  Fig 6: Identifying Diameter Of Exhaust Valve Stem Component
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Valve stem diameter
  
  5.465 to 5.480 mm (0.2151 to 0.2157 in.)
  
  If the valve stem is not as specified, check the oil clearance.
2. Using vernier calipers, measure the valve head margin thickness.
  
  Fig 7: Identifying Valve Head Component Margin Thickness
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Standard margin thickness
  
  1.0 mm (0.039 in.)
  
  Minimum margin thickness
  
  0.5 mm (0.0197 in.)
  
  If the margin thickness is less than the minimum, replace the exhaust valve.
3. Using vernier calipers, measure the valve's overall length.
  
  Fig 8: Identifying Valve Component Overall Length
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Standard overall length
  
  110.40 mm (4.3464 in.)
  
  Minimum overall length
  
  109.90 mm (4.3268 in.)
  
  If the overall length is less than the minimum, replace the exhaust valve.
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.
3. Check the valve face and valve spring seat by using the following procedure:
  
  Fig 9: Identifying Light Coat Of Prussian Blue (Or White Lead) To Valve Component Face
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  1. If Prussian blue appears around the entire valve face, the valve face is concentric. If not, replace the valve.
  2. If Prussian blue appears around the entire valve seat, the guide and valve face are concentric. If not, resurface the valve spring seat.
  3. Check that the valve spring seat contacts in the middle of the valve face with the width between 1.1 and 1.5 mm (0.043 and 0.059 in.).
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 spring seat.
3. Check the valve face and valve spring seat by using the following procedure:
  
  Fig 10: Identifying Light Coat Of Prussian Blue (Or White Lead) To Valve Component Face
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  1. If Prussian blue appears around the entire valve face, the valve face is concentric. If not, replace the valve.
  2. If Prussian blue appears around the entire valve seat, the guide and valve face are concentric. If not, resurface the valve spring seat.
  3. Check that the valve spring seat contacts in the middle of the valve face with the width between 1.1 and 1.5 mm (0.043 and 0.059 in.).
INSPECT INNER COMPRESSION SPRING
1. Using vernier calipers, measure the free length of the inner compression spring.
  
  Fig 11: Identifying Free Length Of Inner Compression Spring Component
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Free length
  
  45.91 mm (1.8075 in.)
  
  If the free length is not as specified, replace the inner compression spring.
2. Using a steel square, measure the deviation of the inner compression spring.
  
  Fig 12: Identifying Deviation Of Inner Compression Spring Component
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Maximum deviation
  
  1.0 mm (0.039 in.)
  
  Maximum angle (reference)
  
  2°
  
  If the deviation is greater than the maximum, replace the inner compression spring.

INSPECT VALVE GUIDE BUSH OIL CLEARANCE

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

Fig 13: Identifying Inside Diameter Of Guide Bush Component
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Bush inside diameter

5.510 to 5.530 mm (0.2169 to 0.2177 in.)

Subtract the valve stem diameter measurement from the valve guide bush inside diameter measurement.

Standard clearance

Item	Clearance
Intake	0.025 to 0.060 mm (0.0010 to 0.0024 in.)
Exhaust	0.030 to 0.065 mm (0.0012 to 0.0026 in.)

Maximum oil clearance

Item	Clearance
Intake	0.08 mm (0.0032 in.)
Exhaust	0.10 mm (0.0039 in.)

For intake side:

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

For exhaust side:

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