Inspecting The Valve Spring - Doosan DX22 Operation & Maintenance Manual

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