Nissan 100NX N14 silhouetteN14

CYLINDER HEAD

EM-42prose procedure
Continued from EM-41

Inspection (Cont'd)

VALVE GUIDE CLEARANCE (continued)

  1. 2
    If it exceeds the limit, check valve to valve guide clearance.
  2. 3
    a. Measure valve stem diameter and valve guide inner diameter. b. Check that clearance is within specification.
    Illustration of measuring valve stem diameter with a micrometer. Label 'Micrometer' points to the measuring tool placed on the valve stem.
    SEM038C
  3. 4
    c. If it exceeds the limit, replace valve or valve guide.

Valve to valve guide clearance (Unit: mm (in))

Intake
Standard0.020 - 0.050 (0.0008 - 0.0020)
Limit0.1 (0.004)
Exhaust
Standard0.040 - 0.070 (0.0016 - 0.0028)
Limit0.1 (0.004)

VALVE GUIDE REPLACEMENT

  1. 1
    To remove valve guide, heat cylinder head to 110 to 120°C (230 to 248°F).
    Illustration of heating the cylinder head in an oil bath to remove the valve guide. The cylinder head is submerged in a heated oil tank; label 'Oil' points to the tank.
    SEM008A
  2. 2
    Drive out valve guide with a press [under a 20 kN (2 t, 2.2 US ton, 2.0 Imp ton) pressure] or hammer and suitable tool.
    Illustration of driving out the valve guide using a press or hammer and suitable tool/drift on the cylinder head; stars/arrows mark the guide locations.
    SEM931C
  3. 3
    Ream cylinder head valve guide hole. Valve guide hole diameter (for service parts): Intake & Exhaust 9.685 - 9.696 mm (0.3813 - 0.3817 in).
    Illustration of reaming the cylinder head valve guide hole using a suitable reamer. Label 'Suitable reamer' points to the reaming tool.
    SEM932C
Valve guide hole diameter (for service parts) - Intake & Exhaust0.3813 - 0.3817 in
9.685 - 9.696mm
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