Doosan DX22 - Inspecting the Valve Spring

10. Cylinder Block/Head
143
Inspecting the Valve Spring
1. Perform a visual inspection of the exterior of the valve
spring.
1) Visually inspect the valve spring for external damage and
replace it if necessary.
2. Check the free length of the valve spring.
EA3M2033
1) Measure the free length of the valve spring with vernier
calipers.
2) If the measurement is below the specification, replace the
valve spring.
3. Check the squareness of the valve spring.
EDL022097A
1) Use a surface plate and straightedge to measure the
squareness of the valve spring.
2) If the measurement exceeds the allowable limit, replace
the valve spring.
4. Check the tension of the valve spring.
EDL022098B
1) Measure the tension of the valve spring with a spring
tester (A).
2) If the measurement is below the allowable limit, replace
the valve spring.
Item Free length
Intake
Inside 59.5 mm (2.3425 in.)
Outside 57.0 mm (2.2441 in.)
Exhaust
Inside 59.5 mm (2.3425 in.)
Outside 57.0 mm (2.2441 in.)
A.
Free length
B.
Squareness
C.
Straightedge
A
B
C
Item Specified value Allowable limit
Intake
Inside
1.5 mm
(0.0591 in.) or less
2.0 mm
(0.0787 in.)
Outside
1.5 mm
(0.0591 in.) or less
2.0 mm
(0.0787 in.)
Exhaust
Inside
1.5 mm
(0.0591 in.) or less
2.0 mm
(0.0787 in.)
Outside
1.5 mm
(0.0591 in.) or less
2.0 mm
(0.0787 in.)
Set length
Spring
tension
Allowable
limit
Intake
Inside
41.0/28.6 mm
(1.6142/
1.126 in.)
14.8/25.0 kg
(32.6284/
55.1156 lb)
±1.5/±2.0 kg
(±3.31/
±4.41 lb)
Outside
44.0/31.6 mm
(1.7323/
1.2441 in.)
25.5/52.3 kg
(56.22/
115.30 lb)
±2.0/±2.5 kg
(±4.41/
±4.42 lb)
Exhaust
Inside
41.0/28.6 mm
(1.6142/
1.126 in.)
14.8/25.0 kg
(32.6284/
55.1156 lb)
±1.5/±2.0 kg
(±3.31/
±4.41 lb)
Outside
44.0/31.6 mm
(1.7323/
1.2441 in.)
25.5/52.3 kg
(56.22/
115.30 lb)
±2.0/±2.5 kg
(±4.41/
±5.51 lb)
A