Komatsu 4D98 Series Shop Manual page 37

3. Inspection and Adjustement
(2)
Spray pattern inspection
After adjustment to the specified valve
opening pressure, use a nozzle tester and
check the spray pattern and seat oil-tight-
ness.
@) Seat oil-tightness check
After injecting a few times, increase
the pressure gradually. Hold the pres-
sure for about 5 seconds at a little be-
fore the valve opening pressure of
1.96 MPa(20 kgf/cm*), and check to
see that oil does not drip from the tip
end of the nozzle.
If extreme oil leak from the overflow
joint exists during injection by the
nozzle tester, check after retightening.
If much oil is leaking, replace the
nozzle assembly.
@ Spray and injection states
l
Operate the nozzle tester lever at a
rate of once or twice a second and
check no abnormal injection.
l
If normal injection as shown below
cannot be obtained, replace the fuel
injection valve.
No extreme difference in angle (6)
No extreme injection angle differ-
ence (a)
Finely atomized spray
Excellent spray departure
Normal
Uniform spray pattern from each nozzle
r ~~~
Abnormal
Extreme difference in angle (9)
Extremely different injection angle (a)
Non-atomized spray
Stagnant spray
3-6