MAINTENANCE MANUAL OF GW4D20/GW4D20B TURBOCHARGED DIESEL ENGINES
182
Great Wall Baoding Internal Combustion Engine
Manufacturing Company Limited
Fig. 4-5-11 Measurement for cylinder bore
Fig. 4-5-12 Measurement for piston outer
diameter
Fig. 4-5-13 Measurement for clearance of
piston ring open end
See Fig. 4-5-11.
Height of measurement
point
①
20mm
If the measured value exceeds the limitation, go to the
Great Wall Authorized Service Station for overhaul.
Cylinder bore group
Mark
Cylinder bore size (φ)
1
83.09~83.10mm
2
83.10~83.11mm
3
83.11~83.12mm
1.3 Checking the piston outer diameter
Use a screw micrometer to measure the piston outer
diameter at the piston group position. See Fig. 4-5-12.
Piston group
Mark
Piston group size (φ)
1
83.1
081
.
0
090
.
0
mm
2
83.1
071
.
0
080
.
0
mm
3
83.1
061
.
0
070
.
0
mm
Cylinder clearance: 0.071~0.090mm.
2. Piston
2.1 Checking the clearance of piston ring open end
Install the piston ring in the cylinder and use a feeler
gauge to check the clearance of piston ring open end.
See Fig. 4-5-13.
Clearance of piston ring open end
Piston ring
Standard
Compression
ring
First compression
ring
0.20~0.40mm
Second
compression ring
0.65~0.85mm
Oil ring
0.25~0.50mm
