Mitsubishi Heavy Industries L2, Руководство по обслуживанию

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29 / 155 Service Manual Mitsubishi L-Series diesel engines
Version 08/2004
MAINTENANCE
ENGLISH
GENERAL
5.9.2 Chattering test
Operate the tester handle at a speed of about one
stroke per second.
1. Needle valve oscillation
If the fuel spray shows good atomization, making
intermittent sounds, and oscillations of the needle
valve are transmitted to the handle, then the noz-
zle is considered as normal.
2. Shape of fuel spray
The nozzle should inject fuel spray straight in the
direction of its axis. A nozzle is defective if it does
not inject steadily or it injects fuel in several sepa-
rate stripes.
A nozzle is defective if it spills fuel accumulated on
the bottom of the nozzle after chattering test. How-
ever, a very small drop of fuel remaining on the tip
of nozzle after chattering test may be regarded as
normal.
5.9.3 Injection Test
1. Operate the tester handle at a speed of 4 to 6
strokes per second.
2. A nozzle should inject fuel spray uniformly in the
shape of a cone.
5.9.4 Checking the compression pressure
Make sure of the following:
1. The engine oil level, air cleaner, starting motor, and
battery are well-conditioned.
2. Warm up the engine to the coolant temperature of
50°C [122°F] or more.
Measure the compression pressure using the following
procedure:
1. The following are the conditions to perform test.
2. Pull the stop lever to the “non-injection” position.
3. Remove the glow plug from the cylinder to be
tested. Set the compression gage adapter to that
cylinder and install the gage.
Figure 27 Chattering test
Good
Bad Bad
Figure 28 After-spilling
Bad
Bad
Good
Figure 29 Testing compression pressure
Engine speed 250 to 280 min
-1
Compression
pressure 2.84 to 3.14 Mpa
(29 to 32 kgf/cm
2
)
[413 to 455 psi]
Pressure difference
between cylinders 0.29 MPa (3 kgf/cm
2
)
[43 psi] or less
Table 15 Conditions to perform test