Qianjiang QJ150T-10, Operation And Maintenance Manual, Page: 88 / 131

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11 Cylinder cover/air cylinder/piston
Preparation data------------------------11.1 Air valve examination------------11.6
Fault diagnosis-------------------------11.2 Displace the valve guide----------11.7
Cylinder head -------------------------11.3 Shaping of the valve seat----------11.8
Examination of the cylinder head--11.4 Installation---------------------------11.9
Air valve-------------------------------11.5
11.1 Preparation data
Matters needing attention in operation
In order to ensure the encapsulation of cylinder cover and cylinder body ， the cylinder cover bears considerable
bolt retightening force. Retightening force value ： 50Nm.
All parts should be cleaned before inspection and test and should be blow dry with high pressure air.
The function of cylinder head: the cylinder head is used to seal the cylinder. It forms a combustion chamber with
the piston, holding combustion gas of high temperature and high pressure. The air intake and air discharge is
realized through the valve mechanism.
Preparation standard Unit::mm
item standard value allowable limi
cylinder pressure 1.25MPa /
flatness of the cylinder cover 0.03 0.03
take in 0.10 0.12
valve clearance
discharge 0.13 0.14
take in 5.00-5.012 5.03 internal diameter of the valve
guard discharge 5.00-5.012 5.03
take in 0.010-0.035 0.08 the clearance between the
valve pole and the valve guard
discharge 0.030-0.05 0.10
take in 1.2 1.7
Valve
valve guard
The width of the valve seat
discharge 1.2 1.7
valve spring free length take in / discharge 35.4 34.9
diameter of the rocker arm hole take in / discharge 10.00-10.015 10.10
diameter of the rocker arm axle take in / discharge 9.982-9.988 9.90
Clearance between rocker arm
hole and the rocker arm axle
take in / discharge 0.012-0.033 0.033
take in 29.78 29.83
rocker arm
the height of cam
discharge 29.54 29.59