Geely JL481Q, Manual

Page: 54 / 198

by its own weight, press valve slightly to connect with valve
seat.
(1) Check fitting quality of valve contact surface and valve
seat:
a. If red lead oil on valve contact surface is distributed in
360º encircling valve center, it indicates that the valve is
coaxial with the surface, otherwise replace the valve.
b. If red lead oil on valve seat is distributed in 360º encircling
valve seat center, it indicates that the guide is coaxial with
the surface, otherwise replace the valve.
c. Check the width and position of valve sealing tape. The
width of valve sealing tape with 45º seat surface should be
1.0-1.4mm. Be noted to control another two cone angles,
making 45º seat surface to be in the middle of surface, a
criterion for qualification (Fig. 89)
(2) If the above requirements cannot be met, correct valve
seat using the following method:
a.If 1.0-1.4mm valve sealing belt on 45º seat surface is a bit
high, use 30º and 45º reamer to shape the valve seat (Fig.
90).(Note: assure valve stem valve seat. Please assure that
the trueness of valve seat and valve stem is 0.030mm.
b. If 1.0-1.4mm valve sealing belt on 45º seat surface is a bit
low, use 60º and 45º reamer to shape the valve seat (Fig.
91).
(3) Grind seat surface after reaming
Manually grind valve and valve retainer seat. Apply a thin
layer of valve abrasive paste on valve seat surface, then use
a rubber sucker with wooden handle to suck valve end
surface, tap valve 45º seat surface while turning the valve,
so as to grind continuous belt with width of 1.4mm (Fig. 92).
Fig. 88 Clean up valve seat
Fig. 89 Check fitting condition on contact surface
Fig. 90 High fitting mark of valve sealing belt
Fig. 92 Grind valve and valve seat manually Fig. 91 Low fitting mark of valve sealing belt
45ºcarbide ceramic reamer
width
50