Service manual
FUEL
INJECTORS
REMOVING
THE
INJECTORS.
1.
Disconnect the high pressure lines from the injectors and
loosen the lines at their attachment to the injection pump
and move them out
of
the way
of
the injectors. Avoid
bending the lines.
2. Remove the fuel return line in its entirety from the top
of
the injectors. Take care not to lose the two sealing washers
and banjo bolt that attaches the fuel return line to each
injector.
3.
71 B Remove the two nuts and washers that hold the
injector on the cylinder head.
71 C Unscrew the injector from the cylinder head.
NOTE:
Clean the area around the base
of
the injector prior to
lifting
it
out
of
the cylinder
head
to help prevent any rust
or
debris from falling down into the injector hole.
If
the injector
will not lift out easily
and
is
held
in by carbon build up
or
the
like, work the injector side to side with the aid
of
an
adjustable
or
open end wrench to free it
and
then lift it out.
4.
The injector seats in the cylinder head on a copper seal-
ing washer. This washer should be removed with the
injector and replaced with a new washer when the injector
is reinstalled.
INJECTION
TESTING
1.
Using the nozzle tester, check the spray pattern and injec-
tion starting pressure
of
nozzle and,
if
it exceeds the limit,
adjust or replace the nozzle. When using nozzle tester,
take the following precautions:
A
CAUTION:
The
spray
injected
from
the
nozzle
is
of
such
velocity
that
it
may
penetrate
deeply
Into
the
skin
of
fingers
and
hands,
destroying
tissue.
If
it
enters
the
bloodstream,
it
may
cause
blood
poisoning
•.
a.
If
the diesel fuel
of
the nozzle tester is stained, replace
it. At the same time, clean or replace the
filter.
h. Set the nozzle tester in a clean place where there is no
dust or dirt.
c.
Mount the nozzle and nozzle holder on the nozzle
tester.
d. Use the fuel at the approximate tempurature
of
20" C (68
0
F)
e. Operate the hand lever
of
nozzle tester several times to
bleed the
air in the nozzle line, then move the hand
lever at intervals
of
one stroke per second while read-
ing the injection starting pressure.
INJECTION
NOZZLE
Start to Injection
71
B/71 C 135 -
140
kg/cm
2
(1920 - 1990
lblin2J
71
B
If
the injection starting pressure
of
the nozzle
is
not
within the limit, loosen the cap nut
on
the nozzle
holder, insert flat screwdriver through the bolt hole
of
the cap nut, then turn the pressure adjusting screw to
set
the injection starting pressure to 200 kglcm2 (2.844
Ib/in2). Then, gradually decrease the pressure until the
injection starting pressure is 135 kglcm2
(1920 Ib/in2).
After the injection starting pressure has been adjusted,
hold the pressure adjusting screw with flat screwdriver,
then tighten the cap nut. Then check the injection
starting pressure again
if
it does not change.
Cap
Nut
Tightening Torque - Injector
71
B 4- 5
m-kg
(8.82 -11.021b)
SCREW
71
B
INJECTION
PRESSURE
ADJUSTMENT
The injection starting pressure for the
71
C injectors
is
adjusted by increasing or decreasing the thickness
of
the
adjusting shim.
The shim has
20 different thickness for every 0.05
mm
(0.0020 in), from 1.0
mm
(0.0393 in) to 1.95
mm
(0.0768 in).
As
0.05
mm
(0.0020 in) is increased, approximately 5.0
kglcm
2
(71.1 Ib/in
2
)
of
injection pressure. When replacing
the shim, grip the retaining nut in a vise and remove the
body with a wrench. Tighten the retaining nut to the
specified torque.
ADJUSTING
SHIM
!
SHIM
THICKNESS
~
j
O.1mm
O.2mm
O.3mm
O.5mm
71
C
INJECTION
PRESSURE
ADJUSTMENT
Engines & Generators
32