cause the rhythmic and clear metal-
lic pounding noise be heard inside the
cylinder.
(2)
Injecting
time
is
too
late to cause
.
the
grave and unclear noise is heard in-
side
the
cylinder.
(3)
Pounding noise can
be
heard inside
the
cylinder after
the
engine starts be-
cause
of
too
large gap
between
the
pis-
ton
and cylinder liner, this noise gets
lower
along mith
the
warming
of
the
en-
gine.
(4)
Too large clearance between the pis-
ton pin and pinhole, clear and sharp
sound,9specialy
when
idling.
(5)
Too large clearance
between
the
main bearing and
the
con - rod bearing,
parts pounding sound is heard
when
the
engine
speed drops suddenly, grave and
strong sound
when
at
low
speed.
(
6)
The axile gap
of
the
crankshaft
is
too
large t pounding notse when idling.
(7)
Valve spring broken, push rod
bent,
valve clearance
too
large and so
on,
dis-
orderly sound
or
lignt and rhythmic poun-
ding sound be heard inside
the
cylinder
head cover.
(
8)
Piston touches valve, metallic poun-
ding sound can be heard beside
the
cyl-
inder
head
(9
) Too large gear clearance, pounding
sound is heard
at
the gear case
when
the speed
• 66 •
angle
2.
adjust
the
fjel delivery advance angle
3. Check
the
cylinder clearance, replace
the piston
or
cylinder liner
4. Replace
the
parts, ass ure
the
stipula-
ted gap
5. Replace
the
parts, assure
the
stipula-
ted
gap
6. Replace
the
thrust
plate, assure stipu-
lated gap
7. Replace the parts ,adjust valve gap
8.
Check valve clearance and transmitting
gear mark
9. Test the gear back lash, replace gear
according
to
the
situation
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