Doosan DP158LDF - Valve Seat; Valve Spring

10. Cylinder block/head
175
Valve Seat
1. Visual inspection: Inspect the damage and wear of
valve seat and if necessary replace.
2. Valve seat thickness and angle: Assemble the valv
es
a
t the cylinder head and using the measuring instru-
ment from the lower face, measure the projecti
on
amount of valve. If the measured value is more than
the use limit, replace the valve seat.
DV2213120A
DV2213121A
3. The disassembly of valve seat cam be pulled out by
means of a special tool with the arc welding done at
two points of valve seat rotating tool or valve seat.
DV2213122A_E
4. Regarding the valve seat assembling, shrink the valve
seat by putting it in the dry ices for about 1 hour or
so, and then press it into the cylinder head by me
ans
of
a special tool.
5. After coating the grinding powder paste on valve h
ead
contacting face of valve seat, and after executing a
suf
ficient lapping operation with the rotating an
d
gr
inding motion of valve, wipe off the grinding agent
thoroughly.
Valve Spring
1. Visual inspection: Check if the exterior of the valve
spring is damaged with the naked eye. Replace it with
a new one if required.
2. Fee length of valve spring: Measure the free lengt
h
of
the valve spring with the vernier clipers. If t
he
r
eading is larger than the specified valve, replace t
he
val
ve spring.
Item Standard Limit
Valve seat thickness
(at cylinder head sur-
face)
0.65 ~ 0.95mm 2.5mm
Item Limit
Valve seat angle
In. Valve
30°
Ex. Valve
45°
10
20
30
40
50
60
70
80
90
0
45
Item Limit
Fee length of valve spring
Inside 65.5mm
Outside 64mm
Cylinder head
Valve sheet
Weld bead