Doosan D1146 - Assembling cylinder head; Rocker arm assembly; Disassembly; Inspection of rocker arm assembly

(4) Valve spring
•
Visual check
Check the appearance of valve spring
and if necessary replace the spring.
•
Valve spring free length
Use a vernier caliper to measure the
valve spring free length.
If the measured value is less than the
specified limit, the valve spring must be
replaced.
•
Valve spring inclination
Use a surface plate and a square to mea-
sure the valve spring inclination.
If the measured value exceeds the spec-
ified limit, the valve spring must be
replaced.
•
Valve spring tension
Use a spring tester to measure the valve
spring tension if the measured value is
less than the specified limit, the valve
spring must be replaced.
- 83 -
EA3M2033
Spring free Length Standard
Intake valve 64 mm
Exhaust
Inner 60 mm
valve
Outer 71 mm
Inclination
Free length
EJM2050I
Square
(unit : mm) Standard Limit
Valve Spring
Inclination
less than 1.8 mm 2.7 mm
EA0M4056
Spring tester
Set Length
Spring
Limit
force
Intake
Valve Spring
valve
Tension at 41mm 70 kg
± 3kg
Set Length
Exhaust
Inner 38 mm 28.6 kg
± 6 %
valve
Outer 41 mm 66 kg
± 5 %