Weichai America Corp.
82
11
APPENDIX A
Appendix A: Tolerance Clearance for Main Parts of Gas Engine (Reference value)
#
Items
Theoretical value (mm)
1
Main bearing clearance
0.063
～
0.138
2
Connecting rod bearing clearance
0.05
～
0.125
3
Crankshaft axial clearance
0.052
～
0.255
4
Connecting rod planar axial clearance
0.15
～
0.35
5
Clearance between the connecting rod small end bushing and
piston pin
0.04
～
0.06
6
Clearance between piston pin hole and piston pin
0.011
～
0.023
7
Clearance between valve stem and intake valve guide pipe
0.025
～
0.054
8
Clearance between valve stem and exhaust valve guide pipe
0.041~0.074
8
Piston ring’s gap in cold
state
The first (top) ring
0.35
～
0.5
The second ring
0.5
～
0.7
Oil ring
0.2
～
0.7
9
Piston ring end face gap in
cold state
The first (top) ring
0.11~0.16
The second ring
0.06
～
0.1
Oil ring
0.03
～
0.17
10
Plane values of valve bottom recess cylinder head
0.05
～
0.10
11
Plane values of cylinder liner top above the engine body
0.05
～
0.10
12
Camshaft axial clearance
0.15
～
0.35
13
Camshaft bearing clearance
0.04
～
0.12
14
Clearance between valve tappet and tappet hole
0.025
～
0.089
17
Valve clearance (cold
state)
Intake
0.5
Exhaust
0.8
18
Clearance between rocker arm and rocker arm shaft
0.012
～
0.066
19
Gear backlash between timing gear and the intermediate gear
0.015
～
0.033
Document Courtesy of Fly Parts Guy Co.
www.FlyPartsGuy.com
Document Courtesy of Fly Parts Guy Co.
www.FlyPartsGuy.com
