Cylinder Head Gasket: Testing and Inspection
1NZ-FE ENGINE MECHANICAL: CYLINDER HEAD (for Hatchback): INSPECTION
1. INSPECT CYLINDER HEAD FOR WARPAGE
(a) Using a precision straightedge and feeler gauge, measure the warpage of the surface that is in contact with the cylinder block and the manifolds.
Text in Illustration
Maximum Warpage:
If the warpage is greater than the maximum, replace the cylinder head.
2. INSPECT CYLINDER HEAD FOR CRACKS
(a) Using a dye penetrant, check the combustion chamber, intake ports, exhaust ports and cylinder block surface for cracks.
If cracked, replace the cylinder head.
3. INSPECT INTAKE VALVE
(a) Check the overall valve length.
Text in Illustration
Standard overall length:
89.25 mm (3.5138 in.)
Minimum overall length:
88.75 mm (3.4941 in.)
If the overall length is less than the minimum, replace the valve.
(b) Using a micrometer, measure the diameter of the valve stem.
Standard valve stem diameter:
4.970 to 4.985 mm (0.1957 to 0.1963 in.)
(c) Check the valve head margin thickness.
Text in Illustration
Standard margin thickness:
1.0 mm (0.039 in.)
Minimum margin thickness:
0.5 mm (0.020 in.)
If the margin thickness is less than the minimum, replace the valve.
4. INSPECT EXHAUST VALVE
(a) Check the overall valve length.
Standard overall length:
87.90 mm (3.4606 in.)
Minimum overall length:
87.40 mm (3.4409 in.)
If the overall length is less than the minimum, replace the valve.
(b) Using a micrometer, measure the diameter of the valve stem.
Standard valve stem diameter:
4.965 to 4.980 mm (0.1955 to 0.1961 in.)
(c) Check the valve head margin thickness.
Standard margin thickness:
1.15 mm (0.045 in.)
Minimum margin thickness:
0.5 mm (0.020 in.)
If the margin thickness is less than the minimum, replace the valve.
5. INSPECT VALVE SPRING
(a) Using a vernier caliper, measure the free length of the valve spring.
Standard free length:
45.05 to 45.15 mm (1.774 to 1.778 in.)
If the free length is not as specified, replace the spring.
(b) Using a steel square, measure the deviation of the valve spring.
Text in Illustration
Maximum deviation:
1.6 mm (0.063 in.)
Maximum angle (reference):
2°
If the deviation is greater than the maximum, replace the spring.
6. INSPECT VALVE GUIDE BUSH OIL CLEARANCE
(a) Using a caliper gauge, measure the inside diameter of the guide bush.
Bush inside diameter:
5.010 to 5.030 mm (0.1972 to 0.1980 in.)
(b) Subtract the valve stem diameter measurement from the guide bush inside diameter measurement.
Standard Oil Clearance:
Maximum Oil Clearance:
If the clearance is greater than the maximum, replace the valve and guide bush Replacement (from 07/2011).
7. INSPECT INTAKE VALVE SEAT
(a) Apply a light coat of Prussian blue to the valve face.
(b) Lightly press the valve against the seat.
(c) Check the valve face and seat according to the following procedure.
Text in Illustration
(1) If blue appears 360° around the face, the valve is concentric. If not, replace the valve.
(2) If blue appears 360° around the valve seat, the guide and face are concentric. If not, resurface the seat.
(3) Check that the seat contact is in the middle of the valve face with the width between 1.0 to 1.4 mm (0.039 to 0.055 in.).
8. INSPECT CAMSHAFT THRUST CLEARANCE
(a) Install the camshafts Installation (from 07/2011).
(b) Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.
Standard thrust clearance:
0.040 to 0.095 mm (0.0016 to 0.0037 in.)
Maximum thrust clearance:
0.11 mm (0.0043 in.)
If the thrust clearance is greater than the maximum, replace the camshaft. If necessary, replace the bearing caps and the cylinder head together.
9. INSPECT CAMSHAFT OIL CLEARANCE
(a) Clean the bearing caps and the camshaft journals.
(b) Place the camshafts on the cylinder head.
(c) Lay a strip of Plastigage across each of the camshaft journals.
Text in Illustration
(d) Install the bearing caps Installation (from 07/2011).
NOTICE:
Do not turn the camshaft.
(e) Remove the bearing caps.
(f) Measure the Plastigage at its widest point.
Standard oil clearance:
0.035 to 0.072 mm (0.0014 to 0.0028 in.)
Maximum oil clearance:
0.08 mm (0.0031 in.)
If the oil clearance is greater than the maximum, replace the camshaft. If necessary, replace the bearing caps and the cylinder head together.
NOTICE:
Completely remove the Plastigage.