ALLrS-CHALMERS
located in the hole of the holder body.
It is essential that the nozzle be per-
fectly centered in the holder nut. A
centering sleeve is supplied in Ameri-
can Bosch kit TSE 7779 for this pur-
pose.
Slide the sleeve over the nozzle
with the tapered end centering in the
holder nut. Tighten the holder nut,
making certain that the sleeve is free
while tightening. Refer to Fig. AC62B.
Test the nozzle for spray pattern
and leakage as in paragraph 148C and
148D.
If the nozzle does not leak under
1700 psi, and if the spray pattern is
symmetrical as shown in right hand
view of Fig. AC61A, the nozzle is
ready for use. If the nozzle will not
pass the leakage and spray pattern
tests,
renew the nozzle valve and seat,
which are available only in a matched
set; or, send the nozzle and holder
assembly to an official diesel service
station for a complete overhaul which
includes reseating the nozzle valve
pintle and seat.
149B.
OVERHAUL OF NOZZLE
HOLDER. (Refer to Fig. AC62C.) Re-
move cap nut (1) and gasket. Loosen
jam nut (2) and adjusting screw (3).
Remove the spring retaining nut (4)
and withdraw the spindle (5) and
spring (6). Thoroughly wash all parts
in clean diesel fuel and examine the
end of the spindle which contacts the
nozzle valve stem for any irregulari-
ties.
If the contact surface is pitted or
rough, renew the spindle. Examine
spring seat (7) for tightness to spindle
and for cracks or worn spots. Renew
the spring seat and spindle unit if the
condition of either is questionable.
Renew any other questionable parts.
Reassemble the nozzle holder and
leave the adjusting screw locknut
loose until after the nozzle opening
pressure has been adjusted as outlined
in paragraph 148E.
INJECTION PUMP
150,
TIMING TO ENGINE. The in-
jection pump should be timed so that
injection occurs at 21 degrees before
top center.
To check and retime the pump to
the engine after the pump is installed
as outlined in paragraph 152A, pro-
ceed as follows:
Crank the engine until No, 1 piston
is coming up on compression stroke
and the engine flywheel mark *TPI"
is in the exact center of the timing
hole.
Remove plugs (P—Fig. AC63)
so that the pump timing marks can
be seen. If the pump timing is correct,
the line mark (50—Fig. AC63A) on
the drive gear hub will be in reg-
ister with the pointer (51) extending
from the front face of the pump. If
the timing marks are not in register,
remove the cover from front of the
Fig.
AC63A—Bosch model PSB injection
pump timing mork (50) is a line on edge
of pump drive hub. The pointer is shown at
(51).
Paragraphs 149B-151
engine timing gear case and loosen
the three cap screws retaining the
pump drive gear to the pump hub.
Using a socket wrench, turn the pump
hub until the timing marks are ex-
actly in register and tighten the drive
gear retaining cap screws.
150A. TRANSFER PUMP. The PSB
injection pumps are equipped with a
positive-displacement, gear-type trans-
fer pump which is gear driven from
the injection pump camshaft. Refer
to Fig, AC63B. To check the operation
of the transfer pump, refer to para-
graph 147B.
If the pump is not operating prop-
erly, the complete pump can be re-
newed as a unit; or, the transfer pump
can be disassembled and cleaned and
checked for improved performance.
Quite often, a thorough cleaning job
will restore the pump to its original
operating efficiency.
151.
HYDRAULIC HEAD. The hy-
draulic head assembly (Fig. AC64)
can be renewed without the use of
special testing equipment. The head
assembly contains all of the precision
components which are essential to ac-
curate pumping, distributing, metering
and delivery of the fuel. To renew
the hydraulic head assembly, first
wash the complete injection pump and
injection lines with clean fuel oil.
Remove the injection lines and dis-
connect the inlet and outlet lines from
Fig.
AC63—To view the Bosch model PSB
injection pump timing marks, it is necessary
to remove plugs (P).
Fig.
AC63B—Cut-away vi^w of model SGB
type fuel transfer pump which is used on
model PSB injection pumps.
Fig.
AC64—Sectional view of Bosch model
PSB injection pump hydraulic head. The
complete head assembly can be renewed
as a unit.
45
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