Nissan 100NX N14 silhouetteN14

Cylinder Head - Inspection (Cont'd)

EM-116prose procedure
Continued from EM-115

Inspection (Cont'd)

Camshaft Sprocket Runout

  1. 1
    Install sprocket on camshaft.
  2. 2
    Measure camshaft sprocket runout. Runout (Total indicator reading): Limit 0.25 mm (0.0098 in)
    Illustration showing a dial indicator measuring camshaft sprocket runout, with the sprocket mounted on the camshaft and rotation arrows indicated.
    SEM929C
  3. 3
    If it exceeds the limit, replace camshaft sprocket.

Valve Guide Clearance

  1. 1
    Measure valve deflection in a parallel direction with rocker arm. (Valve and valve guide mostly wear in this direction.) Valve deflection limit (Dial gauge reading): Intake & Exhaust 0.2 mm (0.008 in)
    Illustration showing a dial gauge measuring valve deflection in a parallel direction with the rocker arm, on a valve installed in the cylinder head. Label notes 'Approx. 15 mm (0.59 in)'.
    SEM003D
  2. 2
    If it exceeds the limit, check valve to valve guide clearance.
  3. 3
    a. Measure valve stem diameter and valve guide inner diameter.
    Illustration showing a micrometer measuring valve stem diameter, with the valve and a micrometer labelled 'Micrometer'.
    SEM938C
  4. 4
    b. Check that clearance is within specification.
  5. 5
    c. If it exceeds the limit, replace valve or valve guide.

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

Intake
Standard0.020 - 0.053 (0.0008 - 0.0021)
Limit0.1 (0.004)
Exhaust
Standard0.040 - 0.073 (0.0016 - 0.0029)
Limit0.1 (0.004)

Valve Guide Replacement

  1. 1
    To remove valve guide, heat cylinder head to 110 to 130 degrees C (230 to 266 degrees F).
    Illustration showing a cylinder head being heated in a container of oil for valve guide replacement, label 'Oil'.
    SEM008A
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