Cylinder Head Assembly: Testing and Inspection
1NR-FE ENGINE MECHANICAL: CYLINDER HEAD: INSPECTION
1. INSPECT CYLINDER HEAD FOR FLATNESS
(a) Using a precision straightedge and a feeler gauge, measure the surfaces that contact the cylinder block and the manifolds for warpage.
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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 intake ports, exhaust ports and cylinder head surface for cracks.
If cracked, replace the cylinder head.
3. INSPECT VALVE SEATS
(a) Apply a light coat of Prussian blue to the valve face.
(b) Lightly press the valve face against the valve seat.
(c) 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.
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(2) If Prussian blue appears 360° around the valve seat, the guide and valve face are concentric. If not, resurface the valve seat.
(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 (0.0394 to 0.0551 in.).
4. INSPECT INTAKE VALVE
(a) Using a gasket scraper and wire brush, scrape off any carbon on the valve head.
(b) Using a vernier caliper, measure the overall length of the valve.
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Standard overall length:
103.35 mm (4.0689 in.)
Minimum margin thickness:
102.85 mm (4.0492 in.)
If the overall length is less than the minimum, replace the valve.
(c) Using a micrometer, measure the diameter of the valve stem.
Valve stem diameter:
5.470 to 5.485 mm (0.21535 to 0.21594 in.)
If the valve stem diameter is not as specified, check the oil clearance.
(d) Using a vernier caliper, measure the valve head margin thickness.
Text in Illustration
Standard margin thickness:
1.0 mm (0.0394 in.)
Minimum margin thickness:
0.5 mm (0.0197 in.)
If the margin thickness is less than the minimum, replace the valve.
5. INSPECT EXHAUST VALVE
(a) Using a gasket scraper and wire brush, scrape off any carbon on the valve head.
(b) Using a vernier caliper, measure the overall length of the valve.
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Standard overall length:
104.5 mm (4.114 in.)
Minimum overall length:
104.0 mm (4.0945 in.)
If the overall length is less than the minimum, replace the valve.
(c) Using a micrometer, measure the diameter of the valve stem.
Valve stem diameter:
5.465 to 5.480 mm (0.21516 to 0.21575 in.)
If the valve stem diameter is not as specified, check the oil clearance.
(d) Using a vernier caliper, measure the valve head margin thickness.
Text in Illustration
Standard margin thickness:
1.15 mm (0.0453 in.)
Minimum margin thickness:
0.65 mm (0.0255 in.)
If the margin thickness is less than the minimum, replace the valve.
6. INSPECT VALVE GUIDE BUSH OIL CLEARANCE
(a) Using a caliper gauge, measure the inside diameter of the guide bush.
Bushing inside diameter:
5.51 to 5.53 mm (0.2169 to 0.2177 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.
7. INSPECT COMPRESSION SPRING
(a) Using a vernier caliper, measure the free length of the valve spring.
Free length:
51.19 mm (2.0154 in.)
If the free length is not as specified, replace the valve spring.
(b) Using a steel square, measure the deviation of the valve spring.
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Maximum deviation:
1.8 mm (0.0709 in.)
If the deviation is greater than the maximum, replace the valve spring.