QUANCHAI N485D, Руководство по обслуживанию

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ANHUI QUANCHAI ENGINE CO., LTD
7. Abnormal sound emitted by diesel engine
Seque
nce
No.
Position
tested
Normal Abnormal
1
Advance
angle of fuel
supply
The advance angle of fuel supply is
16°±1°.
The advance angle of fuel supply
is too large, and there is rhythmic
metal clicking sound in the
cylinder.
2 Nozzle The nozzle pressure is 23 MPa.
The oil-dripping nozzle entangles
with the needle valve, emitting
suddenly clicking sound.
3 Valve
The intake valve clearance is 0.3 mm,
and the exhaust valve clearance is 0.35
mm. The valve clearance is too large
and there are clear rhythmic
knocks.
4 Piston
The clearance of the valve and the
connecting rod bearing is normal.
There are heavy and powerful
knocks when the piston hits the
valve.
5
Cylinder head
gasket
The thickness of the cylinder head
gasket is within the allowable tolerance
range.
The thickness of the cylinder head
gasket is not enough; there are
heavy and powerful knocks when
the piston hits the bottom of
cylinder head.
6
Valve spring,
valve
push
rod and valve
tappet
The valve spring, valve push rod and
valve tappet are within the reasonable
wear-out error range.
The valve spring is broken, the
valve push rod is bent, and the
valve tappet is worn, making the
valve mechanism emit slight
beats.
7
Piston and
cylinder liner
The piston and the cylinder liner are
within the reasonable wear-out error
range.
With large clearance between the
piston and the cylinder liner, the
piston emits excessive noise,
which will be lowered as the
diesel engine heats up.
8
Connecting
rod
bearing
shell
The clearance of the connecting rod
bearing shell is within the range of 0.05-
0.108 mm.
While the clearance of the
connecting rod bearing shell is too
large, a heavy and powerful
impact sound can be heard as the
rotating speed suddenly decreases.
9
Connecting
rod
bushing
and piston pin
The clearance between the connecting
rod bushing and the piston pin is within
the range of 0.025-0.09 mm.
The clearance between the
connecting rod bushing and the
piston pin is too large, and there is
slightly sharp sound, which is
especially clear at idle speed.
10
Crankshaft
thrust bearing
The axial clearance of crankshaft thrust
journal is within the range of 0.085-
0.275 mm.
When the axial clearance of the
worn crankshaft thrust bearing is
too large, the impact sound of the
crankshaft moving back and forth
can be heard at idle speed.