Weichai America Corp.
Revision: August 2019 80
15
APPENDIX C
Appendix C: The Evaluation Criteria for Main Friction Wear of Gas Engine (Reference value)
Wear limit
(mm)
Clearance limit
(mm)
Parts life
(hours)
Closed clearance of the first (top) ring
1.70
-
The height of first ring
0.10
-
Closed clearance of the second ring
1.50
-
The height of second ring
0.10
-
Closed clearance of oil ring
1.50
-
The height of oil ring
0.15
-
The outer diameter of the piston skirt
0.25
0.60
The inner diameter of the cylinder liner
0.50
The outer diameter of the piston pin
0.04
0.10
The inner diameter of the piston pin hole
0.08
The inner diameter of connect rod small end bushing
0.08
The inner diameter of camshaft main journal
0.06
0.10
The inner diameter of camshaft bushing
0.06
The height of cam peach tip
2.00
-
The outer diameter of the cam base circle
0.05
-
The outside diameter of crankshaft journal
0.12
0.15
The diameter of connecting rod bearing bore
0.10
The outer diameter of the crankshaft main journal
0.08
0.15
The inner diameter of main bearing bore
0.10
Thickness of thrust bearing
0.40
-
The subsidence value of intake valve
0.04*d
(1)
Intake valve seals
0.75
Intake valve seat
0.75
The subsidence value of exhaust valve
0.04*d
(1)
Exhaust valve seals
0.85
Exhaust valve seat
0.85
The inner diameter of the intake valve guide
0.06
0.1
The outer diameter of the intake valve stem
0.06
The inner diameter of the exhaust valve guide
0.06
0.1
The outer diameter of the exhaust valve stem
0.06
The inner diameter of rocker arm shaft bushing
0.10
0.12
The outer diameter of rocker arm shaft
0.05
(1) d is the diameter of intake or exhaust valve plate
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