Chery QQ - Table of Main Fit Clearance for SQR472 Engine SQR472; Clearance between Cylinder Hole and Piston Skirt (Piston to Cylinder Clearance); Clearance of Crankshaft Main Bearing; Clearance of Crankshaft Connecting Rod Bearing

Chery QQ Service Manual Mechanical Part of SQR 472Engine
50
Chapter 3. Table of Main Fit Clearance for SQR472 Engine SQR472
1 Clearance between Cylinder Hole and Piston Skirt (Piston to Cylinder Clearance)
Name of Component Size and Tolerance Clearance or Value of
Interferenc
Remark
Cylinder hole
φ72
01.0
0
+
Group X:
72
0.005
0
F
Group S:
72
0.01
0.005
F
Piston skirt
φ72
015.0
025.0
-
-
Divided into two groups:
Clearance for group X:
0.019mm～0.03mm
Clearance of group S:
0.018mm～0.029mm
2 Clearance of Crankshaft Main Bearing
Name of Component Size and Tolerance Clearance or Value of
Interferenc
Remark
Crankshaft main journal φ42h
6–0
。
016
Bearing bushing
2
0
0.006-
Bore of cylinder main bearing
φ46F
6
041.0
025.0
+
+
Clearance 0.025~0.069
3 Clearance of Crankshaft Connecting Rod Bearing
Name of Component Size and Tolerance Clearance or Value of
Interferenc
Remark
Crankshaft connecting rod
journal
φ37h
6
0
016.0-
Bearing bushing
1.5
0
006.0-
Bore of connecting rodbig
end bearing
φ40F
6
041.0
025.0
+
+
Clearance 0.025~0.069
4 Clearance between Piston Pin and Piston Pin Hole
Name of Component Size and Tolerance Clearance or Value of
Interferenc
Remark
Piston Pin Hole
φ18
007.0
002.0
+
+
Piston pin
φ18
001.0
004.0
-
-
Divided into twogroups
Clearance for group A:
0.004 mm～0.0085mm；
Clearance for group B:
0.0045mm～0.009 mm
Notice: When installed
with hand, the piston pin
may pass through the
piston pin hole smoothly
without any obvious
obstruction, otherwise the
piston pin should be
replaced.
5 Inteference between Piston and Small End of Connecting Rod
Name of Component Size and Tolerance Clearance or Value of
Interferenc
Remark
Connecting rod small end
hole
φ18
026.0
044.0
-
-
Value of Interferenc
0.021~0.043