JAC HFC7151M1V-U221B Workshop Manual page 41

3. Valve guide
■ Check the gap between the valve guide and
the valve stem. Replace the corresponding
parts if the measurement is out of limit.
Valve guide
Standard value: 0.020-0.036mm
Limit: 0.10mm
■ Replacement of Valve guide
a. Push out the valve guide towards the cylinder side by the press.
b. Rebore mounting hole on the valve guide of cylinder head to make it match increased size of valve
guide to be installed.
Attention:
■ Do not install the valve guides with the same sizes of old ones. Re-boring mounting hole on
the valve guide of cylinder head
Outer diameter of valve guide:
For the hole with diameter of 10.605-10.615mm,
extend the size of valve guide by 0.05mm.
For the hole with diameter of 10.805-10.815mm,
extend the size of valve guide by 0.25mm.
For the hole with diameter of 11.055-11.065mm,
extend the size of valve guide by 0.50mm.
c. Press the valve guide till its protrusion height
reaches the specified value.
Standard value: 23.0mm
Attention:
■ Use cold pressing method to install valve guide from upper side of cylinder head. Check
whether there are cracks after press fitting.
■ After valve guide pressed in, insert a new valve to check for smooth sliding of valve.
4. Valve Seat
■ Check the valve protrusion height between the end face of valve stem and the surface of valve
spring seat. Replace the valve seat if the limit is exceeded.
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Fig.1.1.047
Valve guide
Outer Diameter of Valve Stem
Inner Diameter of Valve Conduit
Fig.1.1.048
Protrusion
Height
Mechanical Part of
Engine