MAINTENANCE MANUAL OF GW4D20/GW4D20B TURBOCHARGED DIESEL ENGINES
150
Great Wall Baoding Internal Combustion Engine
Manufacturing Company Limited
Fig. 4-3-5 Measuring the free height of valve
spring
Attention:
Check the valve springs visually, and
replace them if any damage or evident abnormal wear
is found.
1.1 Checking the free height of valve spring
(1) Measure the free height of valve spring. See Fig.
4-3-5.
(2) Replace the spring if the height is below the
limitation.
The free height of valve spring
Standard
Limitation
45.0 mm
44.5 mm
Fig. 4-3-6 Measuring the perpendicularity of
valve spring
Fig. 4-3-7 Measuring the tension of valve
spring
1.2 Checking the perpendicularity of valve spring
(1) Measure the perpendicularity of valve spring with a
steel square. See Fig. 4-3-6.
(2) Replace the valve spring if the measured value is
above the limitation. The perpendicularity limitation of
valve spring
1.2·
m
1.3 Checking the tension of valve spring
(1) Press the spring down to the installation height with
a spring tester. Measure the spring tension. See Fig.
4-3-7.
(2) Replace the valve spring if the measured tension
value is below the limitation.
The tension of valve spring
Installation height
Standard
Limitation
32.3 mm
211 N
201 N
2. Valve guide
Attention:
(1) Take caution when clearing away the accumulated
carbon on the valve head, avoiding any damage to the
contact surface of valve seat.
(2) Check carefully for scratch or abnormal wear on the
valve stem. See Fig. 4-3-8.
(3) Replace the valve and valve guide in pairs if there is
any scratch or abnormal wear.
2.1 Checking the valve guide clearance
(1) Measure the outer diameter of valve stem with a
