Cylinder Head: Inspection

INSPECT CYLINDER HEAD FOR FLATNESS

Using a precision straight edge and a feeler gauge, measure the surface contacting the cylinder block and the manifolds for warpage.

Maximum warpage

ITEM SPECIFIED CONDITION CHART

Item	Specified Condition
Cylinder block side	0.05 mm (0.0020 in.)
Intake manifold side	0.10 mm (0.0039 in.)
Exhaust manifold side	0.10 mm (0.0039 in.)

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

Fig 1: Measuring Surface Contacting Cylinder Block And Manifolds For Warpage

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT CYLINDER HEAD FOR CRACKS
1. Using a dye penetrant, check the intake ports, exhaust ports and cylinder surface for cracks. If cracked, replace the cylinder head.
  
  Fig 2: Inspecting Cylinder Head For Cracks
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT VALVE SEATS
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 according to the following procedure:
  1. If Prussian Blue appears 360° around the valve face, the valve face is concentric. If not, replace the valve.
  2. If Prussian Blue appears 360° around the valve seat, the guide and valve face are concentric. If not, resurface the valve seat.
    
    Fig 3: Identifying Valve Seats Width
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. Check that the valve seat contact is in the middle of the valve face with the valve seat width between 1.0 and 1.4 mm (Intake side (0.039 to 0.055 in.)).
  4. Check that the valve seat contact is in the middle of the valve face with the valve seat width between 1.0 and 1.4 mm (Exhaust side (0.039 to 0.055 in.)).

INSPECT CAMSHAFT THRUST CLEARANCE

Install the camshafts (See INSTALLATION ).

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

Standard thrust clearance

ITEM SPECIFIED CONDITION CHART

Item	Specified Condition
Intake	0.06 to 0.155 mm (0.0024 to 0.0061 in.)
Exhaust	0.06 to 0.155 mm (0.0024 to 0.0061 in.)

Maximum thrust clearance

ITEM SPECIFIED CONDITION CHART

Item	Specified Condition
Intake	0.17 mm (0.0067 in.)
Exhaust	0.17 mm (0.0067 in.)

Fig 4: Measuring Thrust Clearance

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

If the thrust clearance is greater than the maximum, replace the camshaft housing. If the thrust surface is damaged, replace the camshaft.

INSPECT CAMSHAFT OIL CLEARANCE

Clean the bearing caps and camshaft journals.
Place the camshafts on the camshaft housing.
Lay a strip of Plastigage across each of the camshaft journals.

Fig 5: Laying Strip Of Plastigage Across Of Camshaft Journals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Install the bearing caps (See INSTALLATION ).
NOTE: Do not turn the camshaft.
Remove the bearing caps (See REMOVAL ).

Measure the Plastigage at its widest point.

Standard oil clearance

ITEM SPECIFIED CONDITION CHART

Item	Specified Condition
Camshaft No. 1 journals	0.030 to 0.063 mm (0.0012 to 0.0024 in.)
Camshaft other journals	0.035 to 0.072 mm (0.0014 to 0.0028 in.)

Maximum oil clearance

ITEM SPECIFIED CONDITION CHART

Item	Specified Condition
Camshaft No. 1 journals	0.085 mm (0.0033 in.)
Camshaft other journals	0.09 mm (0.0035 in.)

Fig 6: Measuring Plastigage At Its Widest Point

NOTE: Completely remove the Plastigage after the inspection.

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

INSPECT COMPRESSION SPRING
1. Using vernier calipers, measure the free length of the valve spring.
  Free length: 53.36 mm (2.1008 in.)
  
  If the free length is not as specified, replace the valve spring.
  
  Fig 7: Measuring Free Length Of Valve Spring
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Using steel squares, measure the deviation of the valve spring.
  Maximum deviation: 1.0 mm (0.0394 in.)
  
  If the deviation is greater than the maximum, replace the valve spring.
  
  Fig 8: Measuring Deviation Of Valve Spring
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT INTAKE VALVE
1. Using a gasket scraper, scrape off any carbon on the valve head.
  
  Fig 9: Cleaning Carbon On Valve Head
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Using vernier calipers, measure the overall length of the valve.
  Standard overall length: 109.34 mm (4.3047 in.)
  
  Minimum overall length: 108.84 mm (4.2850 in.)
  
  If the overall length is less than the minimum, replace the valve.
  
  Fig 10: Identifying Overall Length Of Valve
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Using a micrometer, measure the diameter of the valve stem.
  Valve stem diameter: 5.470 to 5.485 mm (0.2154 to 0.2159 in.)
  
  If the valve stem diameter is not as specified, check the oil clearance.
  
  Fig 11: Measuring Diameter Of Valve Stem
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Using vernier calipers, measure the valve head margin thickness.
  Standard margin thickness: 1.0 mm (0.0571 in.)
  
  Minimum margin thickness: 0.5 mm (0.0197 in.)
  
  If the margin thickness is less than the minimum, replace the valve.
  
  Fig 12: Identifying Margin Thickness Of Valve Head
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT EXHAUST VALVE
1. Using a gasket scraper, scrape off any carbon on the valve head.
  
  Fig 13: Cleaning Carbon On Valve Head
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Using vernier calipers, measure the overall length of the valve.
  Standard overall length: 108.25 mm (4.2618 in.)
  
  Minimum overall length: 107.75 mm (4.2421 in.)
  
  If the overall length is less than the minimum, replace the valve.
  
  Fig 14: Identifying Overall Length Of Valve
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Using a micrometer, measure the diameter of the valve stem.
  Valve stem diameter: 5.465 to 5.480 mm (0.2152 to 0.2157 in.)
  
  If the valve stem diameter is not as specified, check the oil clearance.
  
  Fig 15: Measuring Diameter Of Valve Stem
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Using vernier calipers, measure the valve head margin thickness.
  Standard margin thickness: 1.01 mm (0.0398 in.)
  
  Minimum margin thickness: 0.5 mm (0.0197 in.)
  
  If the margin thickness is less than the minimum, replace the valve.
  
  Fig 16: Identifying Valve Head Margin Thickness
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT VALVE GUIDE BUSH OIL CLEARANCE

Using a caliper gauge, measure the inside diameter of the guide bush.
Bushing inside diameter: 5.510 to 5.530 mm (0.2169 to 0.2177 in.)

Fig 17: Measuring Inside Diameter Of Guide Bush
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Standard oil clearance

ITEM SPECIFIED CONDITION CHART

Item	Specified Condition
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 SPECIFIED CONDITION CHART

Item	Specified Condition
Intake	0.080 mm (0.0031 in.)
Exhaust	0.085 mm (0.0035 in.)

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