Great Wall GW491QE, Service Manual

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EM.2-15
Reinstallation฀/restoration฀of฀cylinder฀head
1. Installation฀of฀cylinder฀gasket
Cylinder฀gasket฀will฀be฀installed฀onto฀the฀device฀plane,฀and฀be฀fixed
using฀positioning฀pin.
2. Installation฀of฀cylinder฀head
The฀cylinder฀head฀component฀may฀be฀installed฀onto฀the฀cylinder฀gasket
on฀device฀unit,฀be฀positioned฀by฀two฀positioning฀pin฀sleeves,฀and฀befixed
using฀ten฀M12฀cylinder-cover฀bolts฀plus฀three฀M8฀cylinder-cover฀bolt
with฀cylinder-cover฀bolts฀&washers .฀Based฀on฀the฀sequence฀indicated
in฀the฀figure,฀a฀wrench฀will฀be฀used฀to฀screw฀ten฀M12฀bolts฀to฀an฀extent
as฀90N m,฀followed฀by฀a฀complete฀unscrewing,฀then฀a฀re-screwing฀to
90N m The฀tightening฀torque฀for฀three฀M8฀bolts฀shall฀be฀20฀N.m.
Finally,฀an฀100%฀verification฀needs฀to฀be฀performed฀using฀a฀fixed฀torque
wrench.
Reinstallation฀/restoration฀of฀cylinder฀head
3. Rocker-shaft฀assembly
(a)Two฀rocker-shafts฀inside฀each฀cylinder฀may฀be฀fixed฀together฀via฀one
special฀clamping฀plate.
(b)The฀rocker-shaft฀assembly฀shall฀be฀installed฀onto฀two฀studbolts฀on
the฀cylinder฀head฀in฀such฀a฀way฀that฀one฀endofrocker-shaft฀having฀dummy
club฀(its฀surface฀facing฀upward)฀will฀be฀backward.
SST฀฀09207-71010
(c)Two฀M8฀nut with฀flat฀washer may฀be฀manually฀screwed฀onto
stud฀bolt;฀Screw฀the฀short฀threaded฀end฀ofthree฀bolts฀(fixing฀the฀rocker-
shaft฀)฀into฀the฀fixed฀seat฀for฀rocker-shaft,฀followed฀by฀a฀tightening฀made
progressively฀in฀two฀steps฀as฀from฀the฀middle฀to฀two฀sides as฀shown
in฀the฀figure .
Tightening฀ torque (18 3)N m
(d)After฀a฀layer฀of฀clean฀machine฀oil฀has฀been฀applied฀to฀the฀ball฀surface
on฀two฀ends฀of฀the฀push฀rod,฀the฀lower฀end฀will฀be฀installed฀into฀a฀ball
socket฀on฀the฀tappet฀cap,฀while฀the฀upper฀end฀will฀be฀pressed฀by฀a฀special
press฀rod฀into฀the฀ ball฀ socket฀of฀rocker-shaft฀while฀the฀ crankshaft฀is
rotating.
4.฀Installation฀of฀valve฀chamber฀cover
Cotton฀cloth฀may฀be฀used฀to฀clean฀sealing฀band฀on฀the฀plane฀of฀cylinder
head,฀after฀which฀valve฀chamber฀cover฀will฀be฀installed฀onto฀three฀bolts
used฀to฀fix฀rocker-shaft฀for฀cylinder฀head;฀when฀the฀rubber฀sealing฀ring฀on
the฀bottom฀of฀valve฀chamber฀cover฀is฀facing฀exactly฀to฀sealing฀band฀on
theplane฀of฀cylinder฀head,components฀like฀bolt&washer฀used฀to฀fix฀three
valve฀chamber฀covers฀will฀be฀installed฀onto฀the฀fixing฀bolt฀of฀rocker-shaft,
followed฀by฀a฀fixing฀with฀three฀cap฀nuts,฀plus฀a฀tightening฀made฀from฀the
middletotwoends.
Tightening฀ torque (5 1)N m
convexity฀position
front
convexity
upward
push฀rod
push฀rod
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