Service manual
FUEL
INJECTORS
INSPECTING
SPRAY
PAnERN
1.
Operate the hand lever
of
the nozzle tester at intervals of
one stroke per second
to
check
if
the fuel
is
injected cor-
rectly in its axial direction. A nozzle is defective
if
it
injects fuel in
an
oblique direction or in several separate
strips. Also, a spray in the form
of
particles indicates a
defect. These defects may sometimes be caused
by
clog-
ging with dust and, therefore, all parts should be carefully
cleaned before reassembly.
FAULTY
ANGLE
~;.
\~
\\\\
FAULTY
DIRECTION
2.
Operate the hand lever to raise the pressure up to 1635
psi (115 kglcm
2
),
which
is
280 psi (20
kglcm2)
lower than
the starting pressure.
If, with pressure applied, fuel does
not drip from the nozzle, oil tightness
is
satisfactory.
Dripping
of
fuel with pressure applied,
is
indicative
of
damage
to
the needle valve or valve body or poor contact
between both. In that event, both needle valve and valve
body should be considered defective and replaced.
. M
CORRECT'M
AFTER
IlUP
TEST
WRONG
DISASSEMBLY
AND
INSPECTION
1.
Clamp the nozzle holder in a vise, remove the nozzle nut
and disassemble the nozzle body, spring, and needle.
2.
Clean the disassembled parts with clean diesel fuel.
NOTE:
Greatest possible
care
should
be
taken
in
handling
the
nozzles as
they
are
precisely
machined.
The
nozzle
and
the
needle valve
are
matched parts.
Do
not mix their
original combinations. Disassemble and
wash
each
noz-
zle assembly
separately.
Carbon
deposits
on
the
nozzle body must
be
removed
with
a piece
of
hard
wood.
However,
it would
be
advis-
able
not
to
clean
the surrounding
area
of
the
nozzle
ori-
fice
to
avoid possible
damage
to
the
orifice.
Iron
dust
on
the
magnetic filter
top
must
be
removed
completely.
5. Assure the needle valve, when it is pushed in the nozzle
body, comes down into the valve seat
by
its weight about
0.7092in (18mm).
If
it does not, replace the assembly.
If
any defect is found, always replace the needle valve
and the nozzle body
as
a unit.
6. Check that there
is
no
flaw
or other damage on mating
surfaces and sliding surfaces
of
the nozzle body and the
needle valve and,
if
present, replace the nozzle assembly.
ASSEMBLING
THE
INJECTOR
1.
Assemble in the reverse order of 4isassembly.
NOTE:
After assembling
the
injector,
test
it.
2. Tighten the nozzle body on the nozzle holder to the speci-
fied torque.
Nozzle
Body
Torque
(24
mm
socket)
8.0
-10 IMt
(58
-72
kg/m)
INSTALLING
1.
Install in the reverse order of removal.
NOTE:
The
copper washers should not
be
reused.
Replace
with new
washers.
2. TIghten the nozzle on the cylinder head
to
the specified
torque.
Nozzle
Torque
(27
mm
socket)
43
-
511b/ft
(6.0
-
7.0
kg/m)
INJECTOR
RETURN
~:::=.
___
lINE
WASHER
ADJUSTING
-----SHIM
SPRING
~;;q-----
NOZZLE
NOZZLE
l-----NUT
~~
__
--
WASHERS
Engines & Generators
35