Chapter IV Disassembly & Repair
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guide completely. Continue to unscrew clockwise the
valve reamer from valve guide.
Tool: valve guide reamer
b) Remove the dirt and scraps on cylinder head thoroughly.
c) Check the valve guide hole. The hole shall be at the central
of valve guide and straight and unobstructed. Insert the
valve and check whether the operation is unobstructed. If
not, the valve guide may have been bent when being
assembled. If it has been bent or damaged, replace it.
d) Check the clearance between the valve stem and guide.
e) The clearance between valve stem and guide: the clearance
between valve stem and guide is calculated by
corresponding inner diameter of valve guide minus the outer
diameter of valve stem.
f) If the clearance between the valve stem and guide exceeds the
maintenance limit, judge whether to replace it with a new guide
can make the clearance in maintenance. If yes, change the valve
guide and stick the valve guide. When replacing valve guide,
please re-repair the valve seat.
5) Valve seat:
a) Remove the carbon deposition in combustor and on
valve seat. Coat a layer of red lead power or other colorful
painting which is easy to scrub and stick.
b) Insert valve and press it for several times, and ensure
not to rotate it on the valve seat. Valve seat coated with
painting indicates it contacts with valve tightly; otherwise,
it does not contact with valve, which means that the valve is not
concentric to valve seat.
c) Grind the valve seat with a 45° grinder to make a smooth
concentric valve seat, clockwise rotation is allowed only.
And the counterclockwise rotation is prohibited.
Tool: valve grinder
d) Narrow and adjust the valve seat with a 32°-45° grinder to
Retaining
ring of valve
guide
Valve guide
Installation
height 1mm
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