CAV-DPA-Pump-Rebuild
Section Ca.6
DESCRIPTION OF THE FUEL INJECTION PUMP
The injection pump is a single-cylinder, opposedplunger, inlet-metering, distributor-type pump fitted
with a mechanical flyweight-type governor and a hydraulically operated automatic advance mechanism. The
pump is flange-mounted on the rear of the engine front
mounting plate and is driven by the timing chain. A
splined quill shaft, having a master spline at each end
Fig. Ca.l
Main fuel filter air bleed points
1. Fuel cut-off tap.
2. Blanking plug.
3. Union screw.
Taxi. Issue 2. 55430
Ca
THE FUEL SYSTEM (Distributor-type Injection Pump)
Fig. Ca.2
Fuel injection pump air bleed points
1. Union nut.
2. Air bleed screw.
3. Air bleed screw.
to ensure correct location, transmits the drive from the
chain wheel to the injection pump drive hub.
A central rotating member forms the pumping and
distributing rotor, and this is driven by the drive hub
through a splined drive shaft on which is mounted the
governor flyweight assembly.
Mounted on the outer end of the pumping and
distributing rotor is a sliding-vane-type transfer pump.
This pump raises the fuel pressure to an intermediate
level, and as its capacity is many times the maximum
requirements of the injection pump a regulating valve,
housed in the pump end plate, allows excess fuel to be
by-passed back to the suction side of the transfer pump.
The pressure regulating valve, in addition to regulating
the pressure of the fuel from the transfer pump, also
provides a means of by-passing the transfer pump when
priming the injection pump. Referring to Fig. Ca.3, it
will be seen that the valve is cylindrical and contains
a small ‘free’ piston, the travel of which is limited by
two light springs. When priming the injection pump, fuel
at lift pump pressure enters the central port in the
regulatingvalve sleeve and moves the ‘free’ piston against
the pressure of the piston retaining spring to uncover the
priming port in the lower end of the valve sleeve. The
priming port is connected by a passage in the end plate
to the delivery side of the transfer pump, thus enabling
the fuel to by-pass the stationary transfer pump and
prime the injection pump.
When the injection pump is in operation fuel at transfer
pressure enters the lower end of the valve sleeve, forcing
the ‘free’ piston upwards against the regulating spring.
As the engine speed increases, the transfer pressure rises,
moving the piston against the pressure of the regulating
spring to progressively uncover the regulating port in
the valve sleeve and allow a metered flow of fuel to bypass back to the inlet side of the transfer pump.
The transfer pressure, therefore, is controlled by a
balance between the regulating spring pressure and the
requirements of the injection pump at any moment.
The pumping and distributing rotor revolves, and is a
Taxi. Issue2. 3125
close fit, in the stationary hydraulic head. The pumping
section of the rotor has a transverse bore containing
twin opposed pumping plungers. These plungers are
operated by means of a cam ring, carried in the pump
housing, through rollers and shoes which slide in the
rotor. The cam ring has four internal lobes operating
in diagonally opposite pairs. The opposed plungers have
no return springs but are moved outwards by fuel under
pressure from the transfer pump, the flow of fuel and
outward displacement of the plungers being determined
by the setting of the metering valve and the speed at
which the pump is rotating. As a result the rollers, which
operate the plungers, do not follow the contour of the
internal cam ring entirely, but will contact the cam lobes
at points which will vary according to the amount of
plunger displacement.
The automatic light load advance mechanism operates
by rotating the cam ring within the pump body. A ballended lever, screwed into the cam ring, is operated by
a piston, one side of which is spring-loaded, sliding in a
cylinder. The other side of the piston is subjected to fuel
at transfer or drain pressure, according to engine load,
which is admitted to the cylinder through the hollow
locating bolt and a port in the cylinder wall. The pressure
of fuel is controlled by the rotary and endwise movement
of the metering valve.
Machined in the surface of the metering valve is a
helical groove. A vertical flat extends upwards from the
helical groove and protrudes beyond the hydraulic head.
A
B
Fig. Ca.3
Section through the end plate and regulating valve
A.
B.
1.
2.
3.
4.
5.
6.
Priming.
Regulating.
Inlet connection.
Sleeve retaining spring.
Nylon filter.
Sleeve guide plug.
Regulating spring.
Regulating sleeve.
7. Regulating piston.
8. Piston retaining spring.
9. Fuel passage to transfer
pump inlet.
10. Regulating port.
11. Fuel passage to transfer
pump outlet.
Ca.5
Ca
THE FUEL SYSTEM (Distributor-type Injection Pump)
Fig. Ca.4
Section through the fuel injection pump
1. Back-leakage connection.
2. Governor spring.
3. Metering valve.
4. End plate and regulating valve.
5. Transfer pump.
6. Hydraulic head.
7. Cam ring.
8. Automatic advance device.
This flat is open to fuel at drain pressure in the governor
housing.
In the surface at the lower end of the metering valve is
machined a flat, the upper edge of which is of the same
pitch as the helical groove. This flat is open to fuel at
transfer pressure.
The width of the land between the helical groove and
the flat at the lower end of the metering valve is slightly
less than the diameter of the timing port in the metering
valve chamber in the hydraulic head. The timing port,
which is situated opposite the metering port, is connected
by a passage in the hydraulic head and the hollow
locating bolt to the port in the advance cylinder.
When the metering valve is in the full-load position
the helical groove in the valve is aligned with the timing
port in the hydraulic head and fuel at drain pressure is
applied to the advance piston. As the drain pressure is
insufficient to overcome the piston spring pressure the
cam ring is held in the fully retarded position.
Under light-load conditions the metering valve is
moved to the low fuelling position, aligning the flat at
the lower end of the metering valve with the timing port.
The advance piston is now subject to fuel at transfer
pressure, and the piston and cam ring move to the fully
advanced position.
Ca.6
9. Pumping plunger.
10. Drive plate.
11. Governor weight assembly.
12. Quill shaft.
The under side of the metering valve is subject to fuel
at transfer pressure which tends to force the valve
upwards. This upward movement of the valve is controlled by an adjustable stop screw, which sets the
relative positions of the helical groove, the flat on the
lower end of the valve, and the timing port so that lightload advance is obtained at the required engine speed.
Machined on each lobe of the cam ring, immediately
after the peak of the cam, is a retraction curve. Under
running conditions, when the injection cycle is completed
the distributing port in the rotor and the outlet port on
the hydraulic head are still in partial alignment with
each other. As the plunger rollers move off the peaks of
the cams the retraction curves allow the plungers to
move slightly outwards. This movement of the plungers
effects a sudden reduction of pressure in the injection
line, so preventing secondary injection and allowing the
injector nozzle needle valve to snap onto its seating to
terminate the spray of fuel into the combustion chamber
without ‘dribble’. When starting the engine the metering
valve is in the full-load position and the advance piston
is subject to fuel at drain pressure. As drain pressure is
not sufficient to overcome the pressure of the advance
piston return spring, the piston and the cam ring remain
in the fully retarded position.
Taxi. Issue 2. 3125
THE FUEL SYSTEM (Distributor-type Injection Pump)
The distributor part of the rotor has a central axial
passage which connects the pumping space between the
plungers with the four inlet ports and single distributing
port drilled radially in the rotor. The radial hole at the
outer end of the rotor is the distributing port, and, as
the rotor turns, this port is aligned successively with
the outlet ports in the hydraulic head, from which the
injectors are fed via external high-pressure pipes. The
inlet or charging ports are equally spaced around the
rotor at an intermediate position, and, as the rotor turns,
these are aligned successively with the inlet or metering
port in the hydraulic head. This port admits fuel to the
rotor under control of the metering valve, which is
mechanically governed.
The mechanical governor is of the flyweight type, the
weights being held in a retainer, which is clamped
between the injection pump drive hub and the drive
shaft and rotates with these components as a single unit.
The weights are a sliding fit in the retainer pockets and
are so shaped that, when under the influence of centrifugal force, they pivot about one edge. A thrust sleeve,
which is a sliding fit on the injection pump drive shaft,
is moved axially by the flyweights. Movement of the
thrust sleeve is transmitted by means of the governor
arm and the spring-loaded hook link to rotate the
metering valve. The governor arm pivots about a fulcrum
on the control bracket and is held in contact with the
thrust sleeve by spring tension. Connection between the
governor arm and the throttle arm and shaft assembly is
made through the governor spring and the idling spring
and its guide.
A shut-off bar, operated by an external lever, rotates
the metering valve to close the metering port.
A
.
Fig. Ca.5
Light-load advance device
Full load.
Low load.
Taxi. Issue2. 81968
A.
B.
1. Transfer pressure.
2. To pumping element.
Ca.
Fig. Ca.6
Mechanical governor
Governor weight.
Governor arm.
Shut-off bar.
Shut-offshaft.
Idling spring.
Governor spring.
Throttle shaft.
8. Linkage hook.
1.
2.
3.
4.
5.
6.
7.
9.
10.
11.
12.
13.
14.
15.
Metering port.
Metering valve,
Timing port.
Control bracket.
Drive shaft.
Thrust sleeve.
Weight retainer.
The metering valve is provided with a vertical slot
along which fuel passes at transfer pressure into the
metering port. The valve is situated in a chamber in the
hydraulic head, into which the diagonally drilled metering
port opens, and rotation of the valve varies the effective
area of the metering port to regulate the flow of fuel to
the pumping and distributing rotor.
When the throttle arm is moved to give increased
speed, the light idling spring is compressed as the guide
is drawn through the governor arm and the governor
spring is tensioned. Tension of the governor spring acting
upon the governor arm and thrust sleeve resists movement of the governor flyweights. As the engine speed
increases, the increasing centrifugal force moves the
flyweights outwards, overcoming the governor spring
tension to move the governor arm and the metering
valve towards the closed position. When the selected
speed has been attained it will be maintained by governor
action. Should the engine speed fall, the flyweights will
move inwards, causing an increase of fuelling which
restores the selected engine speed.
When the throttle arm is in the idling position the
governor spring is untensioned and governing action is
controlled by the light idling spring.
In operation fuel at lift pump pressure enters the pump
through the connection on the pump end plate and passes
Ca.7
Ca
THE FUEL SYSTEM (Distributor-type Injection Pump)
~~
through a fine nylon gauze filter to the inlet side of the
transfer pump.
From the transfer pump the fuel passes through a
passage in the hydraulic head to an annular groove
surrounding the rotor, and thence to the metering valve.
The position of the metering valve depends upon the
setting of the throttle arm which varies the governor
spring pressure on the governor arm. Any variation in
pump speed is accompanied by an increase or decrease
in transfer pressure, which assists in regularing the flow
of fuel into the pumping section of the rotor. The
volume of fuel passing into the pumping element is thus
controlled by the transfer pressure, the position of the
metering valve, and the time during which an inlet port
in the rotor is aligned with the metering port in the
hydraulic head.
When one of the rotor inlet ports is aligned with the
metering port in the hydraulic head, fuel at metering
pressure flows into the rotor and forces the pumping
plungers apart, the amount of plunger displacement
being governed by the quantity of fuel which can flow
into the rotor while the ports are aligned. As the rotor
turns, the inlet port is cut off and the pump plungers
begin to be forced inwards by their rollers bearing on a
pair of cam lobes. This causes an immediate rise in
pressure,,and as the single distributor port in the rotor
comes into register with an outlet port in the hydraulic
head the plungers force the fuel up the central bore of
the rotor and out to the respective injector.
The maximum amount of fuel delivered at one charge
is controlled by limiting the maximum outward movement of the plungers. In Fig. Ca.7 is shown an end-on
view of the rotor, and it will be seen that the cam rollers
are carried in shoes which bear against the ends of the
plungers. The roller shoes, which slide in slots in the
rotor, have specially shaped projecting ‘ears’ which
~
1
A
B
Fig. Ca.8
The injection cycle
A.
Inlet stroke.
B. Injection stroke.
1. Fuel inlet.
2. Pumping and distributing rotor.
3. Pumping plungers.
4. Fuel to injector.
engage eccentric slots in the top and bottom adjusting
plates. Two lugs on the top adjusting plate engage slots
in the bottom adjusting plate to locate the plates one to
the other.
The top adjusting plate is’clamped to the rotor by
the drive plate, the adjusting plate being cut away in
the areas of the drive plate securing screws to permit
adjustment of the plates by rotation. The maximum outward travel of the pump plungers is limited by the ‘ears’
of the roller shoes coming into contact with the curved
slot sides in the adjusting plates. As the slots are eccentric.
rotation of the adjusting plates relative to the rotor
provides a means of adjusting the maximum plunger
stroke.
Section Ca.7
Fig. Ca.7
Maximum fuel adjustment
1. Top adjusting plate.
2. Roller shoe ear.
3. Roller.
Ca.8
4. Pumping end of rotor.
5. Pumping plunger.
REMOVING AND REPLACING THE FUEL
INJECTION PUMP
Thoroughly clean the outside of the injector pump
body, and then disconnect the throttle, stop and kickdown (if fitted) controls. Disconnect the fuel feed and
return pipes from the pump.
Disconnect the high pressure pipes from the pump and
the injectors, remove the clamp and damper bushes and
detach the pipes individually from the engine. Seal the
pump outlet unions with sealing caps 18G 216 to prevent
the ingress of foreign matter.
Unscrew the three nuts with plain washers securing the
injection pump flange to the rear of the engine front plate
and draw the pump rearwards to disengage it from the
engine. Withdraw the quill shaft from inside the injection
pump chain wheel hub.
Taxi. Issue 3. 94241
THE FUEL SYSTEM (Distributor-type Injection Pump)
Before replacing the fuel injection pump it is necessary
to set the static injection timing.
To ensure correct timing relationship between the
injection pump and the engine the injection pump driving
hub, the quill shaft, and the driving flange of the injection
pump chain wheel are provided with master splines; also,
a timing mark, is scribed on the fuel injection pump
mounting flange and an adjustable timing pointer is
secured to the flange of the chain wheel hub.
Before fitting the injection pump to the engine the
position of the timing pointer on the flange of the chain
wheel hub should be checked, using timing gauge
18G 698, and reset if necessary.
A degree plate, fitted to the crankshaft pulley, with a
corresponding pointer on the timing case, is provided to
facilitate ease of timing.
Initial adjustment of the injection timing is provided for
in the injection pump driving flange, the holes for the
bolts which secure it to the chain wheel being elongated.
Crank the engine until the appropriate timing mark
coincides with the timing groove on the crankshaft
pulley. Ensure that No. 1 piston is on its compression
stroke.
Remove the injection pump chain wheel cover-plate
From the front of the timing chain case and note the
position of the master spline in the pump driving flange,
which should now be in the seven o’clock position as
seen-from the front of the engine.
Insert injection timing gauge 18G 698 through the
chain wheel hub, engaging the splined end of the gauge
with the internal splines of the pump driving flange. The
master spline will allow the gauge to engage the driving
flange in one position only. Turn the gauge by hand
(undue force is not necessary) in a clockwise direction,
as seen from the rear of the engine, to take up any
backlash in the injection pump drive mechanism. Hold
the gauge in this position, slacken the two securing
screws, and move the timing pointer to align it with the
slot on the edge of the gauge. Should the movement
required to line up the timing pointer be appreciable,
then initial adjustment should be made by altering the
position of the injection pump driving flange relative to
the chain wheel. This adjustment is made by slackening
the four bolts securing the driving flange to the chain
wheel and carefully turning the driving flange the
required amount by means of the timing gauge. Tighten
the driving flange securing screws and carry out final
adjustment of the timing pointer as described previously
and then remove the timing gauge.
NOTE.-After every occasion of injection pump removal or attention to the crankshaft, camshaft, and timing
gear the position of the timing pointer should be checked,
and reset, if necessary, as described above.
Fit the injection pump quill shaft into the driving
flange.
Rotate the injection pump drive hub and position the
master spline in the drive hub at seven o’clock, when
looking on the drive end of the pump. This will facilitate
the engagement of the quill shaft splines with the drive
hub.
Taxi. Issue 6. 83137
Place a new joint washer in position on the engine front
plate and offer up the injection pump to the engine.
Engage the pump drive hub with the quill shaft and
retain the pump in position by fitting the securing nuts
and washers finger tight. Rotate the injection pump to
align the timing mark on the pump mounting flange
with the timing pointer. Tighten the three nuts to secure
the injection pump in this position.
Refit the high-pressure pipes, and the fuel feed and
drain pipes. Connect the throttle and shut-off controls
and ensure that both controls have their full range of
movement.
Bleed the fuel system as described in Section Ca.5.
Maximum and idling speed adjustments
After fitting either a new or overhauled injection pump
the engine maximum light running speed and the idling
speed must be checked, and adjusted if necessary. Before
making either of these adjustments it is imperative that
the engine air cleaner is correctly serviced and fitted.
Run the engine until it has attained its normal running
temperature-thisis most important. Ensure that the shutoff control is in the fully open position and remove the
locking sleeve from the maximum speed adjusting screw.
Using a tachometer to check the engine speed, adjust
the maximum speed stop screw to give a maximum light
running speed of 3,700 r.p.m., thus giving a maximum
road governed speed of 3,500 r.p.m. Tighten the locknut.
Fit the locking sleeve and seal it with wire and a lead
seal, using sealing pliers 18G 541.
Adjust the idling stop screw to give an idling speed of
600 r.p.m. and tighten the locknut.
Section Ca.8
DISMANTLING AND REASSEMBLING THE
FUEL INJECTION PUMP
Dismantling and servicing of the fuel injection pump
should only be carried out by specially trained personnel,
Fig. Ca.9
Checking the position of the injection pump timing
pointer, using timing gauge 18G 698
Ca.9
Ca
THE FUEL SYSTEM (Distributor-type Injection Pump)
and the Service tools and special test equipment referred
to in the following instructions should be available. The
workshop in which these operations are carried out
should be absolutely clean and the atmosphere free from
dust or dirt. It is also recommended that components
are immersed in clean Shell Calibration Fluid ‘C’
immediately after they are dismantled from the main
assembly to protect them from possible damage and
corrosion and to prevent the ingress of foreign matter.
Abrasives should never be used for cleaning as the
resulting damage would seriously impair both the
efficiency and the working life of the pump. The components should be washed in clean Shell Calibration
Fluid ‘C’, but they must not be wiped with cotton waste,
rags, or cloth wipers of any kind.
Cut the sealing wire, remove the cover-plate and joint
washer from the side of the pump housing, and drain the
fuel oil from the pump.
Withdraw the quill shaft from the drive hub and
mount the pump on assembly base 18G 633 A secured
in a vice.
Remove the banjo pipes from the hydraulic head.
Unscrew the self-locking nuts with plain washers and
reniove the shut-off lever and throttle arm from their
shafts. Remove the dust cover from each shaft. Cut the
locking wire, unscrew the two control cover securing
nuts, and remove the two flat washers. Press the throttle
shaft downwards and withdraw the control cover complete with shut-off shaft and adjusting screws. Remove
and discard the control cover to pump housing gaskets.
Press back the locking tabs and unscrew the two
control cover studs and the small set screw securing the
control bracket to the pump housing. Remove the keep
plate and tab washers, then lift the complete control
bracket assembly together with the metering valve and
shut-off bar from the pump housing. Remove the shut-off
bar from the control bracket. Disconnect the metering
valve from the linkage hook and protect its precisionground surface by immersing it in a bath of Shell Calibration Fluid ‘C’. Unscrew the self-locking nut and remove
the nylon pivot washer to release the linkage hook from
the governor arm. Disconnect the throttle shaft link from
the governor spring and remove and discard the two ‘O’
seals from the throttle shaft. Disconnect the governor
spring from the idling spring guide and withdraw the
guide and spring from the governor arm. Remove the
governor arm spring to release the governor arm from
the control bracket.
Turn the pump upside-down and slacken both the
spring cap and the end plug in the advance device
housing until the pressure of the maximum advance stop
spring inside the advance device housing is relieved.
IJnscrew the cap nut and the head locating bolt, both
of which have aluminium and rubber sealing washers.
and remove the advance device housing. Unscrew and
remove the advance screw from the cam ring. Remove
and discard the advance device housing gasket.
Unscrew the end plug and the spring cap, noting the
adjusting shim inside the cap. Withdraw the spring, stop,
ca.10
slide washer, and piston from inside the advance device
housing. Remove and discard the ‘O’ seals from the
spring cap and end plug.
Slacken the fuel inlet connection and then remove the
screws and studs securing the end plate to the hydraulic
head. Carefully remove the carbon vanes from their slots
in the transfer pump rotor and withdraw the transfer
pump liner.
Unscrew the fuel inlet connection and carefully withdraw the components of the regulating valve from the
end plate in the following order: sleeve retaining spring,
nylon filter, regulating plug, reguIating spring, valve
sleeve with piston and joint washer, and lastly the piston
retaining spring.
Hold the drive hub with drive shaft screw assembly
tool 18G 659 and, using box spanner 18G 634 in conjunction with a standard ratchet wrench, slacken the transfer
pump rotor. The word ‘OFF‘ and an arrow etched on
the exposed face of the rotor indicate the direction in
which the rotor is unscrewed.
Unscrew and remove the two hydraulic head locking
screws, one of which carries an air vent valve, and carefully withdraw the hydraulic head and distributing rotor
assembly from the pump housing. Remove the ‘0’seal
from the groove in the periphery of the hydraulic head.
Unscrew the transfer pump rotor, taking care not to
allow the pumping and distributing rotor assembly to fall
out from the hydraulic head.
Stand the hydraulic head assembly on the bench with
the drive plate uppermost. Hold the drive plate with
assembly spanner 18G641 and unscrew the two drive
plate securing screws. Remove the drive plate, lift off
the top adjusting plate, and withdraw the rollers and
roller shoes from the pumping and distributing rotor.
Withdraw the rotor from the hydraulic head and remove the bottom adjusting plate. Refit the rotor to the
hydraulic head, and to protect the working surfaces
immerse the assembly in a bath of clean Shell Calibration
Fluid ‘C’.
Withdraw the cam ring from the pump housing,
noting the arrow etched on the visible face of the cam
ring. The arrow is to assist when reassembling, and ifs
direction corresponds with the direction of pump rotation, as shown on the pump nameplate.
Compress the cam ring locating circlip, using circlip
pliers 18G 1004, and withdraw the circlip from inside the
pump housing.
Hold the drive hub with drive shaft screw assembly
tool 18G 659 and, using torque adaptor 18G 664 and a
standard socket wrench, unscrew the drive shaft screw
from inside the drive hub, reversing the procedure shown
in Fig. Ca.12. The splined drive shaft complete with
governor weights assembly may now be withdrawn from
inside the pump housing.
Remove and discard the ‘0’seal from the drive shaft
and remove the weight retainer, weights, thrust washer,
and sleeve from the drive shaft.
Withdraw the drive hub from inside the pump housing
Taxi. Issue 6. 83137
THE FUEL SYSTEM (Distributor-type Injection Pump)
and remove the spring washer and support washer from
their location inside the drive hub. The washers are
removed by turning them end on inside the drive hub and
withdrawing them along the master spline. Two flats are
machined on the outside diameter of the support washer
to facilitate this operation.
Remove the drive hub oil seal from the pump housing,
using oil seal extractor tool 18G 658.
Wash all components thoroughly in clean Shell Calibration Fluid ‘C’. Cotton waste, rags, or cloth wipers
must not be used to wipe the components. If necessary,
unscrew the plug with sealing washer, using rotor plug
spanner 18G 652, and blow out the internal passages in
the pumping and distributing rotor with compressed air.
Coat the threads of the plug with Araldite and refit and
tighten the plug to 28 Ib. in. (.32 kg. m.).
Push out the pumping plungers, one at a time, for
inspection, noting that the end of the plunger which has
been in contact with the roller shoe is polished and
should be replaced in this position. Examine the working
surface of the plungers and the plunger bore in the pumping and distributing rotor for wear and abrasions. The
bore of the hydraulic head and its mating surface in the
rotor should also be examined for wear and scoring.
Should any of these parts be worn, the pumping and
distributing rotor and hydraulic head, which are mated
assemblies, must be renewed as a unit.
Some injection pumps are fitted with hydraulic heads
having an oversize metering valve bore and an oversize
metering valve to suit. Oversize metering valves, which
are identified by a machined groove, are available, but
only hydraulic heads having a standard-size metering valve
bore are supplied as replacements. Injection pumps fitted
with oversize metering valves are identified by the number
6.375 etched upon the hydraulic head between the outlet
connections adjacent to the metering valve bore.
Inspect the plunger rollers for flats and the cam ring
lobes for signs of wear. Test the roller shoes in their
A51471
Fig. Ca.10
Holding the drive plate with spanner 18G 641 when
unscrewing the drive plate securing screws
Taxi. Issue3. 6394
Ca
Fig. Ca.ll
Removing the drive hub oil seal, using oil seal extractor
18G 658
guides in the pumping and distributing rotor for correct
action and freedom of movement.
Check the drive shaft splines for wear, assemble the
drive shaft to the drive plate, and ensure that there is no
excessive radial movement between the drive shaft and
plate.
Test the fit of the vanes in their slots in the transfer
pump rotor. The vanes should be a sliding fit when
lubricated with fuel oil.
Inspect the bore of the regulating valve sleeve for wear
and ensure that the valve piston can move freely along
the whole length of the sleeve bore.
Inspect all springs for fractures and check them against
new counterparts for length. Weak or fractured springs
should be renewed. Check the governor weight retainer,
thrust washer, and thrust sleeve against new counterparts
for signs of wear.
When reassembling, thoroughly rinse all components
in freshly filtered clean Shell Calibration Fluid ‘C‘ and
assemble all parts wet.
Fit a new drive hub oil seal to the pump housing,
driving it onto its seat with oil seal guide 18G 663. Insert
oil seal inspection plug 18G 660 into the oil seal. A
correctly fitted oil seal will show a continuous black line
when viewed through the flange end of the oil seal
inspection plug.
Fit the support washer and spring washer into the
drive hub. Remove the oil seal inspection plug and pass
the drive hub through the seal, seating the drive hub
flange against the pump housing.
Place the governor weight retainer on plate 18G662
and pass locating pin 18G 661 through the weight
retainer to locate in the plate so that the weight retainer
Ca.11
Ca
THE FUEL SYSTEM (Distributor-type Injection Pump)
is trapped between the plate and the shoulder of the
locating pin. Place the weights, equally spaced, in
position on the weight retainer.
The slot in each weight should be uppermost and
nearest the locating pin (Fig. Ca. 13). Each weight should
be aligned with a pocket in the weight retainer and with
its inner end against the locating pin. Place the thrust
washer and thrust sleeve on the locating pin and resting
on the governor weights. The thrust sleeve must be fitted
with the flange having the projection uppermost. Exert
downward pressure on the thrust sleeve and the assembly
will enter the weight retainer. Withdraw the locating pin
and remove the assembly from the plate. Slide the assembly onto the drive shaft. Fit protection cap 18G 657 over
the drive shaft splines and fit a new ‘0’ seal in the
machined groove on the shaft. Insert the drive shaft and
weight assembly into the pump housing and engage the
drive shaft splines with the splines in the drive hub. Fit
the drive shaft screw, and, holding the drive hub with
drive shaft screw assembly tool 18G659, tighten the
drive shaft screw to the figure given in ‘GENERAL
DATA’, using torque adaptor 18G664 and torque
wrench 18G 537 (Fig. Ca.12).
Compress the cam ring locating circlip, using circlip
pliers, 18G 1004, and seat it against the shoulder in the
‘boreof the pump housing. Place the cam ring in position
against the circlip. The direction of the arrow on the
visible face of the cam ring must conform with the
direction of pump rotation as marked on the pump
nameplate. Fit the cam advance screw finger tight to
locate the cam ring and check the ring for freedom of
movement in the pump housing.
If the hydraulic head and pumping and distributing
rotor are renewed, ensure that the direction of the arrow
!SA
Fig. Ca.12
Holding the drive hub with drive shaft screw assembly
tool 18G 659 while tightening the drive shaft screw
with torque adaptor 18G664 and torque wrench
18G 537
Ca.12
Fig. Ca.13
Assembling the governor weights, thrust washer, and
thrust sleeve into the weight retainer, using Service
tools 18G 661 and 18G 662
stamped on the periphery of the pumping end of the rotor
corresponds with the pump rotation, as indicated on the
pump nameplate.
Withdraw the pumping and distributing rotor complete
with plungers from the hydraulic head. Place the top
adjusting plate in its correct position on the rotor-that
is, with the slot in the periphery of the adjusting plate
aligned with the scribed mark on the periphery of the
pumping end of the rotor (Fig. Ca.14).
Fit the drive plate to the rotor with its relieved face
next to the top adjusting plate. The slot in the periphery
of the drive plate must be in line with the scribe mark
on the periphery of the rotor (Fig. Ca.14). Tighten the
drive plate securing screws lightly to hold the top
adjusting plate in position on the rotor. Invert this
assembly so that the distributing end of the rotor is uppermost. Slide the rollers into their shoes and insert the
roller and shoe assemblies into their guides in the rotor,
ensuring that the contour of the roller shoe ears conforms
with the contour of eccentric slots in the top adjusting
plate. Assemble the bottom adjusting plate to the rotor
with the contour of the eccentric slots in the adjusting
plate conforming to the contour of the roller shoe ears
and the slots in the periphery of the bottom adjusting
plate engaging the lugs on the top adjusting plate. Fit
the assembly of the pumping and distributingrotor to the
hydraulic head and fit and lightly tighten the transfer
pump rotor. Stand the assembly of the hydraulic head
and the pumping and distributing rotor on the bench with
the pumping end of the rotor uppermost.
Fit relief valve timing adaptor 18G 653 A, preset at 15
atmospheres, to high-pressure outlet ‘V’ on the hydraulic
head and connect up the whole assembly to injector
nozzle testing machine 18G 109 A (Fig. Ca.15).
Operate the handle of the test machine and turn the
pumping and distributing rotor in the normal direction of
Taxi. Issue3. 6394
THE FUEL SYSTEM (Distributor-type Injection Pump)
rotation until the pumping plungers are forced outwards
to the maximum fuel position. Set the roller-to-roller
dimension, using a micrometer, to the dimension given
in ‘GENERAL DATA’. Move the adjusting plates
(clockwise to increase and anti-clockwise to decrease the
dimension) with maximum fuel adjusting probe 18G 656.
Tighten the drive plate securing screws to the figure given
in ‘GENERAL DATA’, using torque wrench 18G 537.
This setting is approximate, final adjustment being made
with the pump mounted on a power-driven test machine
(see Section Ca.9). The drive plate is held, when tightening the securingscrews, with assembly drive plate spanner
18G 641. Disconnect the test machine and the hydraulic
adaptor from the hydraulic head.
Fit a new oil seal into its groove in the machined
periphery of the hydraulic head.
Turn the pump drive shaft in the pump housing and
position the master spline at 12 o’clock. Align the master
spline in the drive plate with the metering valve bore in
the hydraulic head. Lubricate the periphery of the
hydraulic head and the bore of the pump housing
liberally with clean Shell Calibration Fluid ‘C'. Hold the
hydraulic head assembly square with the axis of the pump
housing and, with the metering valve bore at 12 o’clock,
push the hydraulic head into the pump housing. Rotate
the drive shaft slightly to assist the engagement of the
shaft with the drive plate.
Insert the two hydraulic head locking screws, leaving
them finger tight and ensuring that the screw with the
vent valve is fitted immediately above the pump nameplate.
Mount drive shaft screw assembly tool 18G 659 in the
splined drive hub and, using torque wrench 18G 536 and
assembly box spanner 18G 634, tighten the transfer pump
rotor to the figure given in ‘GENERAL DATA’.
Fit the transfer pump liner and insert the carbon vanes
into the slots in the transfer pump rotor.
Ensure that the transfer pump liner locating peg is in
position ‘C’ in the pump end plate.
Insert the piston retaining spring into the regulating
valve bore in the end plate, ensuring that it is properly
seated in the bottom of the bore. Fit a new seal washer
Fig. Ca.14
Assembly the top adjusting plate and the drive plate
with the slots in their peripheries aligned with the
scribed mark on the pumping end of the rotor
Taxi. Issue 4. 88664
Ca
Fig. Ca.15
Setting the roller-to-roller dimension, using a micrometer and Service tools 18G 109 A and 18G 653 A
to the small-diameter end of the regulating valve sleeve
and insert the valve piston into the sleeve. Insert the
regulating spring into the large-diameter end of the valve
sleeve. Place the regulating plug on the top of the sleeve
with its spigoted end engaging the sleeve bore. Fit the
sleeve retaining spring onto the guide. Pass the nylon
filter, small-diameter end leading, over the spring and
regulating plug onto the shoulder of the valve sleeve.
Insert this assembly, valve sleeve first, into the bore of
the end plate and secure it in position with the fuel inlet
connection and washer.
Position a new oil seal in its recess in the upper face of
the hydraulic head and fit the assembled end plate to the
head, engaging the locating peg on the inner face of the
Fig. Ca.16
Tightening the transfer pump rotor, using torque
wrench 18G536 and Service tools 18G 659 and 18G634
Ca.13
Ca
THE FUEL SYSTEM (Distributor-type Injection Pump)
end plate with the slot in the periphery of the transfer
pump liner. The end plate securing screw holes are
unequally spaced to ensure correct assembly of the end
plate to the hydraulic head. Tighten the set screws and
studs to the torque figure given in ‘GENERAL DATA’,
using torque wrench 18G 536. Tighten the fuel inlet connection to the torque figure in ‘GENERAL DATA’,
using torque wrench 18G 537.
Tighten the cam ring advance screw to the figure given
in ‘GENERAL DATA’, using torque wrench 18G 372.
Check the cam ring for freedom of movement.
Place a new advance device housing gasket in position
on the pump housing with the flat of the ‘D’-shaped
hole at the drive hub end of the pump. To ensure satisfactory sealing this gasket should be assembled dry.
Assemble the advance device housing to the pump
housing, using new rubber and aluminium sealing
washers for the head locating bolt and cap nut. Using
torque wrench 18G 537, tighten the head locating bolt,
the cap nut, and the two head locking screws to the
figures given in ‘GENERAL DATA’. Check the cam
ring for freedom of movement.
Fit new ‘0’seals to the light-load advance piston plug
and the spring cap, using protection cap 18G 640 to pass
the seals over the threads.
Insert the slide washer and piston, in that order, into
the advance device housing on the side where the fuel
oil drilling enters the piston bore. Screw in the piston
plug. Insert the maximum advance stop, and spring, in
that order, into the remaining open end of the advance
unit housing and screw in the cap. Tighten the piston
plug and spring cap to the torque figures given in
‘GENERAL DATA’, using torque wrench 18G 537.
Insert the metering valve into the metering valve bore
in the hydraulic head.
Engage the governor arm with the control bracket
and connect the governor arm spring to both components.
Fit the assembly governor arm and control bracket to
the pump housing. The lower end of the governor arm
should engage the outside face of the thrust sleeve flange.
Place the keep plate in position with its open end towards
the shut-off bar. Fit new tab washers with their pointed
tabs towards the governor arm. Secure the keep plate in
position with the two governor control cover studs. Fit
the small screw and tab washer at the metering valve end
of the control bracket. Tighten the control cover studs to
the torque figure given in ‘GENERAL DATA’, using
torque wrench 18G 536. Lock the studs in position by
bending up the pointed tabs. Tighten the small screw to
the torque figure given in ‘GENERAL DATA’, and lock
it with the tab washer.
Assemble the spring retainer, spring, and fibre washer
onto the governor linkage hook, in that order. Pass the
threaded end of the linkage hook through the governor
arm. Fit the pivot ball washer onto the linkage hook
and screw on the linkage nut about three turns. Press
back the spring retainer and attach the linkage hook to
the metering valve. The hook end should turn towards
the metering valve.
Set the internal dimension between the metering valve
Cu.14
Fig. Ca.17
Setting the internal dimension between the metering
valve lever pin and the control cover stud with the
vernier heldparallel to the axis of the pump
lever pin and its nearest control cover stud to the length
given in ‘GENERAL DATA’, using a vernier gauge as
shown in Fig. Ca.17. Adjustment is made by slackening
or tightening the hook linkage nut. During this operation
light pressure should be applied to the governor arm
in the direction of the metering valve and the vernier
gauge should be held parallel to the pump axis.
Locate the idling spring on the idling spring guide.
Insert the guide into hole No. 2 in the governor arm
(Fig. Ca.6) and connect the governor spring to the idling
spring guide.
Insert the plain end of the shut-off bar into the slot
in the control bracket and position the shut-off bar under
the tab of the control cover stud locking washer.
Using protection cap 18G 564, fit the lower ‘O’seal to
the shut-off shaft. Fit the upper ‘0’seal, using protection
cap 18G 665. Pack the groove between the ‘0’seals with
Shell Alvania No. 2 grease. Press the shut-off shaft into
its bore in the control cover. The peg which engages the
shut-off bar should be close to the inside edge of the
control cover, and should be left projecting slightly above
the control cover face.
Place a new control cover gasket in position on the
pump housing, ensuring that the locating tabs of the
gasket engage the slots under the keep plate. To ensure
satisfactory sealing this gasket should be soaked in Shell
Calibration Fluid ‘C‘ before assembly.
Fit new lower and upper ‘0’seals to the throttle shaft,
using protection caps 18G 654 and 18G 665. Pack the
groove between the ‘0’seals with Shell Alvania No. 2
grease. Connect the free end of the governor spring to
hole No. 2 (2-2-litre engine) or hole No. 1 (2.52-litre
engine) in the throttle shaft link (Fig. Ca.6).
Press the throttle shaft into its bore in the control
cover. Place the control cover in position on the control
cover studs. Ensure that the shut-off shaft peg engages
the shut-off bar and pull the shut-off shaft fully home
as the control cover is lowered onto the gasket. Fit new
sealing washers on the control cover studs and fit and
Taxi. Issue 4. 88664
THE FUEL SYSTEM (Distributor-type Injection Pump)
Ca
tighten the stud nuts to the torque figures given in
‘GENERAL DATA’, using torque wrench 18G 536. Place
the dust caps on the throttle and shut-off shafts. Fit the
throttle arm and the shut-off lever to their respective
shafts and secure them in place with their nuts and
washers.
Section Ca.9
TESTING AND ADJUSTING THE FUEL
INJECTION PUMP
After overhaul the fuel injection pump must be checked
functionally, and the maximum fuel output adjusted if
necessary. These tests and adjustments are carried out on
a power-driven test bench embodying the necessary
vacuum and pressure gauges and equipment to test the
fuel transfer pump and a graduated glass to measure the
injection pump back-leakage. In addition, the tools
mentioned in the following paragraphs are also required.
NOTE.-The following precautions must be observed
when testing the pump:
(1) Ensure that the power-driven test bench is set to run
in the direction of rotation of the injection pump, as
indicated by the arrow on the pump nameplate.
Serious damage may be caused to the pump if it is
run in the reverse direction.
(2) Ensure that the fuel flow at the pump inlet is not
less than 1,000 c.c./min. If this flow cannot be
obtained, a maximum feed pressure of 2 lb./sq. in.
(15 kg./cm.2) is permissible.
(3) Do not run the pump for long periods at high speed
with low fuel output.
(4) Do not run the pump for long periods with the shutoff control in the closed position.
After checking the direction of rotation mount the
pump on the test bench and connect up the drive. Fit
radial connections to the hydraulic head in place of the
banjo pipes. Using high-pressure pipes 6 mm. x 2 mm. x
865 mm. (34 in.) long, connect the radial connections to
a matched set of test nozzles. The test nozzles should be
Type BDN.12.SD.12 mounted in nozzle holders Type
BKB.50.SD.533b (formerly BKB.5O.SD.19b) and set to
open at 175 atmospheres.
Ensure that the pump throttle arm has the full range
of movement by unscrewing fully the idling and maximum
speed stop screws.
Remove the hydraulic head locking screw, not the one
incorporating the vent valve, and connect the pressure
gauge by means of a flexible pipe to transfer pressure
adaptor 18G 636, which is screwed into the head locking
screw hole.
Connect the feed pipe, preferably of the transparent
type, to the fuel inlet connection on the injection pump
end plate. The vacuum gauge should be fitted, by means
of a ‘T’ coupling, to the feed pipe.
Connect the inlet connection on the measuring-glass
to the drain connection on the pump housing and the
drain cock on the measuring-glass to the return pipe on
the test bench by means of flexible pipes.
Taxi. Issue 4. 6394
Fig. Ca.18
Checking the automatic advance device, using
advance gauge 18G 638 B
Remove the small set screw from the centre of the
advance unit housing spring cap and assemble automatic
advance gauge 18G 638 B to the spring cap with the
degree scale and pointer uppermost and the scale set to
zero.
Throughout the following operations and tests the pump
throttle and shut-off levers must be in the fully open
position, except where stated otherwise.
The pump and the feed pipe must now be filled and
primed as follows:
(1) Connect the fuel feed pipe to the drain connection
on the pump housing.
(2) Open both of the vent screws on the injection
pump(3) Turn on the gravity feed. When test oil free from
air bubbles flows from the vent screw on the
hydraulic head, close this vent screw. Wait till the
test oil flowing from the vent screw in the governor
control housing is free from air bubbles, then close
this vent screw also.
(4) Rotate the pump drive through 180° and repeat
operations (2) and (3).
(5) Fit the feed and return pipes to their respective
connections.
(6) Slacken the high-pressure pipe unions at the
injector end.
(7) Start the test machine and run at 100 r.p.m. until
oil free from air bubbles issues from the injector
pipe connections.
(8) Tighten the injector pipe connection while the test
machine is running.
The following tests are designed to check, in turn, each
of the separate functions of the injection pump. Before,
however, making these individual tests a general check
should be carried out to ensure oil-tightness of all joint
washers, oil seals, and pipe connections while the pump
is running and when stationary.
(1) Transfer pump vacuum test
Start the test machine and run the pump at
100 r.p.m.
Ca.15
I
Ca
THE FUEL SYSTEM (Distributor-type Injection Pump)
(6) Fuel delivery check
A9255
Fig. Ca.19
Adjusting the maximum fuel setting, using Service
tool 18G 656
Turn the test oil feed cock to the 'off' position
and note the depression registered on the vacuum
gauge. This should build up to 16 in. (406mm.) Hg
within 60 seconds maximum. Check the fuel feed
pipe unions for air leaks, indicated by the presence
of air bubbles in the pipe line. If necessary,
tighten the feed pipe unions and carry out a further
test.
NOTE.-Do not run the pump for periods exceeding 60 seconds with the test oil supply turned off.
After the vacuum test is completed turn on the
test oil supply, and with the pump running at
100 r.p.m. air-vent the pump by means of the vent
valve on the hydraulic head locking screw.
(2) Transfer pump pressure
With the pump running at 100 r.p.m. note the
pressure registered on the pressure gauge which
should read 12 lb./sq. in. (-8 kg./cm.2).
(3) Transfer pump pressure
Increase the pump speed to 800 r.p.m., when a
pressure of 32 to 44 lb./sq. in. (2.3 to 3.1kg/cm.2
should be registered on the pressure gauge.
Without altering any of the adjustments, check
that the fuel delivery at 800 r.p.m. is 3.6 to 4.4 C.C.
per 200 shots. Remove the shut-off lever adjustment tool.
(7) Advance check
Run the fuel pump at 800 r.p.m. Move the shutoff lever to the fully closed position and check
that the advance reading is 31/2 to 41/2°. Fit and seal
the metering valve adjustment screw sealing cap
with wire and a lead seal, using sealing pliers
18G 541.
NOTE-If for any reason it is found necessary
to tighten or slacken the governor control cover cap
nuts, the settings made at (4) and (5) will be disturbed, and operations (4), (5), (6), and (7) should
be repeated.
(8) Back-leakage
Set the shut-off lever fully open and the throttle
arm fully closed. Run the pump at 1,000 r.p.m.
and measure the back-leakage through the graduated measuring-glass. The back-leakage should be
5 to 50 C.C. per 100-shot cycle.
(9) Maximum fuel setting
NOTE:-Throughout this test the advance gauge
must show a zero reading.
Run the pump at 1,000 r.p.m. with both controls
in their fully open position, when the average
delivery for 200 shots from all four test injectors
should be 6..9+/-.1 C.C. In arriving at this figure
compare the delivery from all injectors to ensure
that the difference in output from any two does
not exceed ,6 C.C. Before taking a reading the test
oil in the measuring-glasses should be allowed to
settle for 15 seconds and the measuring-glasses
should be allowed to drain for 30 seconds before
a fresh test is made.
To adjust the pump output stop the test bench
and turn the test oil feed cock to the 'off' position.
Remove the cover-plate from the side of the pump
(4) Fuel delivery setting
Run the pump at 800 r.p.m., and after slackening
the locknut alter the metering valve adjustment
screw till a zero reading is obtained on the automatic advance gauge. Tighten the locknut and recheck the advance reading. Fit the shut-off lever
adjustment tool 18G697 to the fuel pump and
adjust the shut-off lever to obtain an average fuel
delivery of 3.6 to 4.4 C.C. per 200 shots. Ensure that
the advance gauge still shows a zero reading.
(5) Advance setting
Run the pump at 800 r.p.m. Slacken the metering
valve adjustment screw locknut and alter the
adjustment screw to obtain an advance reading of
13/4° to 21/4°.Tighten the locknut and re-check the
advance reading.
Ca.16
Fig. Ca.20
The shut-off lever adjuster 18G697 mounted on the
fuel injection pump and test bench
Taxi. Issue4. 6394
THE FUEL SYSTEM (Distributor-type Injection Pump)
Ca
(11) Cut-off test
With the shut-off lever held in the fully closed
position run the pump at 200 r.p.m. The average
delivery for 200 shots, with the throttle arm in
the fully open position, should not exceed 1.0 C.C.
(12) Throttle operation
Run the fuel pump at 200 r.p.m. with the throttle
arm in the fully closed position. The average
delivery with the shut-off lever fully open should
not exceed 1.0 C.C. per 200 shots.
(13) Fuel delivery check
With both controls fully open run the fuel pump
at 1,650 r.p.m. and record the average delivery
per 200 shots.
Fig. Ca.21
Tightening the drive plate screws, using torque wrench
18G 537 and torque adaptor 18G 655A
housing to provide access to the interior of the
pump. Slacken the two drive plate securing screws
sufficiently to permit movement of the adjusting
plates. Turn the pump drive until the slots in the
peripheries of the drive plate and the top adjusting
plate are visible through the aperture in the pump
housing. Engage the end of the maximum fuel
adjusting probe 18G 656 in the slot in the top
adjusting plate and tap the tool with a light
hammer to move the plate in the required direction.
The adjusting plate is turned in the same direction
as the normal direction of the pump rotation to
increase the maximum output. Movement of the
adjusting plate in the opposite direction will
decrease the maximum output. This operation
must be carried out very carefully as the amount
of movement required will be very small. Tighten
the drive plate securing screws to the torque figure
given in ‘GENERALDATA’, using tools 18G 537,
and 18G 655A. While tightening the screws the
torque wrench must be in line with the spanner
(Fig. Ca.21). After making this adjustment replace
the cover-plate and carry out the complete filling
and priming operation. Re-check the fuel delivery
and, if necessary, re-adjust the pump output.
(10) Fuel delivery
Decrease the pump speed to 100 r.p.m. and check
the output. The average delivery for 200 shots
under these conditions should not be less than
that obtained when setting the pump maximum
fuel output minus 1.5 C.C. When carrying out this
test use 30 seconds’ measuring-glass draining time
and allow the test oil to settle for 15 seconds
before taking a reading.
Taxi. Issue 7. 83137
(14) Governor setting
Increase the pump speed to 1,850 r.p.m. and set
the throttle arm by means of the maximum speed
adjustment screw to give a maximum average
delivery of 1.0 C.C. per 200 shots. No line should
exceed 1.8 C.C. Tighten the adjustment screw
locknut.
(15) Fuel delivery check
Reduce the pump speed to 1,650 r.p.m. and recheck the fuel delivery. The average delivery now
should not be less than that recorded in operation
(13) minus .4 C.C. per 200 shots.
(16) Timing setting
This setting is made, after all the foregoing tests
have been completed, with the pump removed
from the power-driven test bench.
It should be noted that, unlike the ‘in-line’ fuel
injection pump, which has a static commencement
of injection point, the point at which commencement of injection occurs in the distributor-type
fuel injection pump varies according to the fuel
requirements of the engine. The timing of the
distributor-type pump is carried out with the
pumping plungers set to delivery maximum fuel on
No. 1 injection line and with the plunger rollers
in contact with the cam lobes: therefore, after all
occasions of pump overhaul or adjustment to the
pump output it is imperative that the pump timing
is checked, and the timing mark on the pump
flange re-marked if necessary.
Remove the cover-plate from the side of the
pump housing and the four redial connections
from the hydraulic head. Connect injector nozzle
testing machine 18G 109 A to outlet ‘V’ on the
hydraulic head to means of relief valve timing
adaptor 18G 653 A. The relief valve must be set to
operate at 30 atmospheres.
Turn the pump drive hub in the normal direction
of rotation until the timing mark ‘E’ on the drive
plate becomes visible through the aperture in the
side of the pump housing. Operate the handle of
the test machine to apply a pressure of 30 atmospheres to the pump. This will force the pumping
Ca.17
Ca
THE FUEL SYSTEM (Distributor-type Injection Pump)
plungers outwards to the limit of their travel as
the drive hub is turned. Continue turning the drive
hub in the normal direction of rotation until
resistance is encountered. With the pump held in
this position mount flangemarking gauge 18G 648A,
preset to 86°, on the pump quill shaft. Check that
the timing mark on the pump flange lies along the
scribing guide on the flange marking gauge. If
necessary, delete the old timing mark and scribe a
new mark by drawing a scribing tool along the
guide on the flange marking gauge.
Disconnect the pump from the test machine
and fit the banjo pipes to the hydraulic head. Refit
the cover-plate to the side of the fuel pump
housing and seal the securing screws with wire and
a lead seal, using sealing pliers 18G 541.
Maximum and idling speed adjustments
These adjustments are carried out after the pump has
been installed on the engine, and are detailed in Section
Ca.7.
Section Ca.10
ALTITUDE SETTINGS
Each vehicle leaves the Factory with its maximum fuel
setting adjusted for sea-level conditions. If the vehicle is
to be operated continuously above sea-level, adjustment
of the injection pump is necessary to set the maximum
fuel delivery to conform with the figures given in the
following table.
Moximum fuel output for 200
A57660.
Fig. Ca.22
Scribing the timing mark on the fuel injection pump
mounting flange, using Service tool 18G 648 A
When testing the injectors for spray and adjusting
the injectors for service the nozzle opening pressure should be set to 130 atmospheres for 2.2-litre
engines and 135 atmospheres for 2.52-litre engines.
The needle lift should be .029 to .035 in. (.75 to
-90 mm.) for 2.2-litre engines and 4 to .75 mm. for
2-52-litre engines.
Section Ca.12
LIFT PUMP
Follow the instructions given in Section C.l, but after
replacing the lift pump bleed the fuel system as described
in Section Ca.5.
Altitude
1
0 to 2,000 ft.
(0 to 600 m.)
6.8 to 7.0 C.C.
2,000 t o 4,000 ft.
(600 t o 1200 m.)
6.4 to 6.6
C.C.
8.3 to 8.5
4,000 to 6,000 ft.
(1200 to 1800 m.)
6.0 t o 6.2
C.C.
7.7 t o 7.9 C.C.
6,000 t o 8,000 ft.
(1800 to 2400 m,)
5.6 to 5.8 C.C.
7.2 to 7.4
c.c.
8,000 to 10.000 ft.
(2400 to 3000 m.)
5.1 to 5.3 C.C.
6.6 to 6.8
c.c.
10,000 to 12,000 ft.
(3000 to 3600 m.)
4.7 to 4.9
6.1 to 6.3
C.C.
c.c.
Section Ca.13
c.c.
Section Ca.11
FUEL INJECTORS
Follow the instructions given in Section C.6, noting
the following points.
Ca.18
MODIFIED INJECTION PUMP
(Type DPA.3248050A)
This pump is as described in Section Ca.6 but with
various detail modifications to improve engine governing
and the addition of an anti-stall device. The modifications
include a governor spring, idling spring, and maximum
advance stop spring of new load rates. Other modifications incorporated in this pump are to the metering valve,
quill shaft, and banjo pipes.
The anti-stall device consists of an adjusting screw,
which protrudes from the drive end of the control cover,
and a locknut. In operation the inner end of the adjusting
screw contacts the governor arm to act as a stop. The
effect of this is to prevent the governor from reducing
the metering area below the position permitted by the
anti-stall screw. Therefore, adjustment of the anti-stall
screw should only be carried out as described in Section
Ca.13 under 'Maximum and idling speed adjustments'.
Taxi. Issue 7. 83137
THE FUEL SYSTEM (Distributor-type Injection Pump)
Removing and replacing
Follow the instructions in Section Ca.7 noting that the
correct injection timing for this pump is 26° B.T.D.C.
Maximum and idling speed adjustments
After fitting either a new or overhauled injection pump,
adjust the engine maximum light running speed as
described in Section Ca.7. Then proceed as follows to
adjust the idling speed and anti-stall device:
(1) With the engine stopped unscrew the anti-stall
screw until it is out of contact with the governor
arm.
(2) Start the engine, ensure that it is at its normal
running temperature, and adjust the idling stop
screw to set the engine speed at between 450 and
500 r.p.m.
(3) Screw in the anti-stall screw carefully until a slight
speed increase is noticed, then unscrew one third
of a turn and lock in position with the locknut.
(4) Readjust the idling stop screw to set the idling
speed at 500 r.p.m. and tighten the idling stop screw
locknut.
(5) Test the anti-stall screw setting by running the
engine at about 3,000 r.p.m. and then releasing
the throttle:
(a) If the engine stalls the pump is underdamped
and the anti-stall screw should be screwed in
slightly, relocked, and the setting retested.
(b) If the engine deceleration is slow or sluggish
the pump is overdamped and the anti-stall
screw should be screwed out slightly, relocked,
and the setting retested.
(6) Check that the engine stops when the shut-off lever
is operated.
NOTE.-After every adjustment of the anti-stall screw
ensure that the engine idling speed is controlled by the
idling stop screw and not by the anti-stall screw.
Dismantling and reassembling
Follow the instructions in Section Ca.8 noting that this
pump is .fitted with four governor weights.
Testing and adjusting
Mount the pump on a test bench and fill and prime
the pump as described in Section Ca.9. Check the oiltightness of all joint washers, oil seals, and pipe connections with the pump running and when stationary. Then
proceed with the following tests, noting that the pump
throttle arm and shut-off lever must be in the fully open
position except where stated otherwise.
(1) Transfer pump vacuum test
Start the test machine and run the pump at 100
r.p.m.
Turn the test oil feed cock to the 'off position
and note the depression registered on the vacuum
gauge. This should build up to 16in. (406 mm.) Hg
within 60 seconds maximum. Check the fuel feed
pipe unions for air leaks, indicated by the presence
Taxi. Issue 5. 6394
of air bubbles in the pipe line. If necessary, tighten
the feed pipe unions and carry out a further test.
NOTE.-Do not run the pump for periods exceeding 60 seconds with the test oil supply turned off.
After the vacuum test is completed turn on the
test oil supply, and with the pump running at
100 r.p.m., air vent the pump by means of the vent
valve on the hydraulic head locking screw.
(2) Transfer pump pressure
With the pump running at 100 r.p.m. note the
pressure registered on the pressure gauge, which
should read 11 lb./sq. in. (.8 kg./cm.2).
( 3 ) Transferpump pressure
Increase the pump speed to 1,300 r.p.m. when a
pressure of 43 to 54 lb./sq. in. (2.9 to 3.8 kg./cm.2)
should be registered on the pressure gauge.
(4) Fuel delivery setting
Run the pump at 1,300r.p.m. and after slackening
the locknut alter the metering valve adjustment
screw till a zero reading is obtained on the automatic advance gauge. Tighten the locknut and
recheck the advance reading. Fit shut-off lever
adjustment tool 18G 697 to the fuel pump and
adjust the shut-off lever to obtain an average fuel
delivery of 6.2 to 7.0 C.C. per 200 shots.
Ensure that the advance gauge still shows a zero
reading.
(5) Advance setting
Run the pump at 1,300r.p.m. Slacken the metering valve adjustment screw locknut and alter the
adjustment screw to obtain an advance reading of
13/4 to 21/4 °. Tighten the locknut and re-check the
advance reading.
(6) Fuel delivery check
Without altering any of the adjustments check
that the fuel delivery at 1,300 r.p.m. is 6.2 to 7.0
C.C. per 200 shots. Remove the shut-off lever
adjustment tool.
(7) Advance check
Run the fuel pump at 1,300 r.p.m. Move the
shut-off lever to the fully closed position and check
that the advance reading is 33 to 43". Fit and seal
the metering valve adjustment screw sealing cap
with wire and a lead seal, using sealing pliers
18G 541.
NOTE.--If for any reason it is found necessary
to tighten or slacken the governor control cover cap
nut the settings made at (4) and (5) will be disturbed and operations(4), (5), (6), and (7) should
be repeated.
(8) Back-leakage
Set the shut-off lever fully open and the throttle
arm fully closed. Run the pump at 1,000 r.p.m.
Ca.19
THE FUEL SYSTEM (Distributor-type Injection Pump)
and measure the back-leakage through the graduated measuring-glass. The back-leakage should be
5 to 50 C.C. per 100 shot time cycle.
Maximum fuel setting
NOTE.-Throughout this test the advance gauge
must show a zero reading.
Run the pump at 1,000 r.p.m. with both controls
in their fully open position, when the average
delivery for 200 shots from all four test injectors
should be 6-9+/-.1 C.C. In arriving at this figure
compare the delivery from all injectors to ensure
that the difference in output from any two does
not exceed .6 C.C. Before taking a reading the test
oil in the measuring-glasses should be allowed to
settle for 15 seconds and the measuring-glasses
should be allowed to drain for 30 seconds before a
fresh test is made.
To adjust the pump output, stop the test bench
and turn the test oil feed cock to the ‘off’ position.
Remove the cover-plate from the side of the pump
housingto provide accessto the interior of the pump.
Slacken the two drive plate securing screws sufficiently to permit movement of the adjusting plates.
Turn the pump drive until the slots in the peripheries of the drive plate and the top adjusting
plate are visible through the aperture in the pump
housing. Engage the end of the maximum fuel
adjusting probe 18G656 in the slot in the top
adjusting plate and tap the tool with a light
hammer to move the plate in the required direction.
The adjusting plate is turned in the same direction
as normal pump rotation to increase the maximum
output. Movement of the adjusting plate in the
opposite direction will decrease the maximum
output. This operation must be carried out very
carefully as the amount of movement required will
be very small. Tighten the drive plate securing
screws to the torque figure given in ‘GENERAL
DATA’, using tools 18G 537 and 18G 655A.
While tightening the screws the torque wrench
must be in line with the spanner (Fig. Ca.21).
After making this adjustment replace the coverplate and carry out the complete filling and priming
operation. Re-check the fuel delivery and, if necessary, re-adjust the pump output.
Fuel delivery
Decrease the pump speed to 100 r.p.m. and check
the output. The average delivery for 200 shots
should now be not less than that obtained when
setting the pump maximum fuel output minus 1.5
C.C. When carrying out this test use 30 seconds
measuring-glass draining time and allow the test
oil to settle for 15seconds before taking a reading.
Ca.20
(11) Cut-off test
With the shut-off lever held in the fully closed
position run the pump at 200 r.p.m. The average
delivery for 200 shots, with the throttle arm in the
fully open position should not exceed .8 C.C.
(12) Throttle operation
With the throttle arm in the fully closed position
unscrew the anti-stall screw until it is out of contact
with the governor arm and tighten the locknut.
Run the pump at 200 r.p.m. with the throttle arm
still fully closed. The average delivery with the
shut-off lever fully open should not exceed 1.0 C.C.
per 200 shots.
(13) Fuel delivery check
With both controls fully open run the fuel pump
at 1,630 r.p.m. and record the average delivery per
200 shots.
(14) Governor setting
Increase the pump speed to 1,850 r.p.m. and set
the throttle arm by means of the maximum speed
adjustment screw to give a maximum average
delivery of 1.0 C.C. per 200 shots. No line should
exceed 1.8 C.C. Tighten the adjustment screw
locknut.
(15) Fuel delivery check
Reduce the pump speed to 1,630 r.p.m. and recheck the fuel delivery. The average delivery now
should not be less than that recorded in operation
(13) minus -4 C.C. per 200 shots.
(16) Timing setting
This setting is made, after all the foregoing tests
have been completed with the pump removed from
the power-driven test bench.
It should be noted that, unlike the ‘in-line’ fuel
injection pump, which has a static commencement
of injection point, the point at which commencement of injection occurs in the distributor-type
fuel injection pump varies according to the fuel
requirements of the engine. The timing of the distributor type pump is carried out with the pumping
plungers set to deliver maximum fuel on No. 1
injection line and with the plunger rollers in
contact with the cam lobes: therefore, after all
occasions of pump overhaul or adjustment to the
pump output it is imperative that the pump timing
is checked, and the timing mark on the pump
flange remarked if necessary.
Remove the cover plate from the side of the
pump housing and the four radial connections
from the hydraulic head. Connect injector nozzle
testing machine 18G 109 A to outlet ‘V’on the
hydraulic head by means of relief valve timing
adaptor 18G 653 A. The relief valve should be set
to operate at 30 atmospheres.
Turn the pump drive hub in the normal direction
of rotation until the timing mark ‘E’ on the drive
Taxi. Issue 5. 6394
THE FUEL SYSTEM (Distributor-type Injection Pump)
plate becomes visible through the aperture in the
side of the pump housing. Operate the handle of
the test machine to apply a pressure of 30 atmospheres to the pump. This will force the pumping
plungers outwards to the limit of their travel as
the drive hub is turned. Continue turning the drive
hub in the normal direction of rotation until
resistance is encountered. With the pump held in
this position mount flangemarking gauge 18G648A,
pre-set to 86°, on the pump quill shaft. Check that
the timing mark on the pump flange lies along the
scribing guide on the flange marking gauge. If
necessary delete the old timing mark and scribe a
new mark by drawing a scribing tool along the
guide on the flange marking gauge.
Disconnect the pump from the test machine and
fit the banjo pipes to the hydraulic head. Refit the
cover-plate to the side of the fuel pump housing
and seal the securing screws with wire and lead
seal, using sealing pliers 18G 541.
Altitude settings
Follow the instructions in Section Ca.10.
Ca
(5) Lift off the air cleaner body and intake hose as an
assembly. Note the rubber air seal between the
cleaner body and the intake manifold on the
engine.
Refitting
(6) Reverse the procedure in (1) to (5).
Section Ca.16
INJECTION PUMP (2.52-litre diesel engine)
The pump is as described in Sections Ca.6 and Ca.13,
but with a type number DPA 3249F520 and the setting
code stamped on the pump nameplate.
Later engines are fitted with a modified pump. This
pump is as described above, but with a type number
DPA 3342F110 and having two springs fitted to the
linkage hook instead of a single spring.
Removing and replacing
Follow the instructions in Section Ca.7, noting that the
correct injection timing for this pump is 23° B.T.D.C.
Maximum and idling speed adjustments
Follow the instructions given in Section Ca.13.
Section Ca.14
AIR CLEANER (Oil Bath Type)
Removing
(1) Release the clips and detach the air inlet tube and
the breather hose from the air cleaner body.
(2) Remove the screws retaining the air cleaner
assembly to the left-hand valance.
(3) Lift out the air cleaner assembly.
Refitting
(4) Reverse the procedure in (I) to (3).
Section Ca.15
AIR CLEANER (Dry Type)
Removing
(1) Remove the drive screw retaining the air intake
hose clip to the radiator frame.
(2) Release the clip and detach the breather hose from
the air cleaner intake.
(3) Remove the central wing nut, detach the air cleaner
top cover and remove the element.
(4) Release the air cleaner body from its support
bracket.
Taxi. Issue 7. 94241
Dismantling and reassembling
Refer to the instructions given in Section Ca.13 and
Section Ca.8.
Testing and adjusting
Conditionsfor test
1. The test equipment must be set to drive the pump
in the direction of rotation indicated on the pump
nameplate.
2. Fuel available at the injection pump inlet must be
1000 c.c./min. flow minimum, or 2 lb./sq. in.
(-15 kg./cm.2)pressure maximum.
3. Test injectors must be a matched set with type
BDN.12.SD.12 nozzles operating at 175 atmospheres.
4. Injector pipes should be 6 mm. x 2 mm. x 34 in.
(865 mm.) long.
5. The injection pump throttle and shut-off levers
must be in the fully open position except where
otherwise stated.
6. All fuel delivery figures are for 200 shots.
7. Allow 30 seconds glass draining time and 15
seconds settling time when taking fuel delivery
readings.
8. The maximum fuel delivery given in the test plan is
for sea-level conditions. For continuous use above
sea-level see Section Ca.10 for maximum fuel
settings.
Ca.21
Ca
THE FUEL SYSTEM (Distributor-type Injection Pump)
Test plan for pumps DPA 3249F520 and DPA 3342F110: Setting code A45/1200/4/3700
Test No.
l.
2.
~
1
1
I
4.
5.
I
6.
Description
R.P.M.
Requirements
Remarks
Fuel supply turned off. After test,
air-vent from hydraulic vent screw
at 100 r.p.m.
Transfer pump vacuum
100
16 in. (406 mm.) Hg
within 60 seconds
Transfer pressure
100
1 1 lb./sq. in.(.8 kg./cm.2)
minimum
Transfer pressure
1,200
Advance position
1,200
to 2°
Use metering valve adjustment
screw to obtain this reading.
Advance position
1,800
to
Metering valve adjustment as in
test 4. Shut-off lever fully closed.
Lock valve adjustment screw and
seal it using tool 18G 541.
Backleakage
1,200
3 to 50 C.C. for 100 stroke
time cycle
Throttle lever fully closed.
Maximum fuel delivery
1,200
9.0
C.C.
average.
Spread between lines not
to exceed 1.0 C.C.
Adjust output by moving adjusting
plate relative to drive plate with
tool 18G 656. Tighten drive plate
screws to correct torque with tool
18G 655 A.
Average as test 7 minus
3.2 C.C.
This is a minimum delivery figure.
Average delivery 0.8
maximum
Shut-off lever fully closed.
58 to 78 lb./sq. in.
(4.1to 5.5 kg./cm.2)
-
7.
I
Fuel delivery check
8.
9.
1
I1
I
I1
Cut-off operation
Throttle operation
C.C.
Average delivery 1.0 C.C.
maximum
Throttle lever fully closed and antistall screw unscrewed and locked.
Record delivery
Fuel delivery check
1,650
12.
Governor setting
1,850
Average delivery 1.8 C.C.
maximum. No line to
exceed 2.5 C.C.
Set throttle lever with maximum
speed adjustment screw.
Lock stop screw.
13.
Fuel delivery check
1,650
Average delivery as in
test 1 1 minus 0.4 C.C.
This is a minimum figure. Throttle
set as in test 12.
11.
~
14.
Governor setting
1,850
-
Average delivery of 1-8 C.C.
~~
-
~
~~
Set throttle with maximum speed
adjustment screw. Lock stop screw.
Adaptor 18G653 A (set at 30
atmospheres) connecting 18G 109A
to outlet 'V'. Apply fuel pressure,
rotatedrivehubwithtool 18G648A
(set at 86°) and mark pump flange
with scriber.
Ca.22
Taxi. Issue 7. 94241
KEY TO THE DISTRIBUTOR-TYPE FUEL INJECTION PUMP COMPONENTS
No.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
Description
End plate.
Locating pin.
Screw for end plate.
Stud for end plate.
Nut for stud.
Piston retaining spring.
Regulating piston.
Regulating sleeve.
Washer for sleeve.
Filter.
Regulating plug.
Regulating spring.
Sleeve retaining spring.
Inlet connection.
Washer for inlet connection.
Transfer pump rotor.
Transfer pump blade.
Transfer pump liner.
Transfer pump seal.
Hydraulic head and rotor assembly.
Rotor plug.
Washer for plug.
Hydraulic head seal.
Banjo pipe.
Bolt for banjo pipe.
Washer for bolt.
Fuel feed pipe connection.
Olive for fuel feed pipe.
Hydraulic head locking screw.
Washer for screw.
Hydraulic head vent screw assembly.
Vented locking screw for hydraulic head.
Vent screw.
Adjusting plate (bottom).
Roller shoe.
Roller
Adjusting plate (top).
Drive plate.
Drive plate screw.
Cam ring.
Locating circlip for cam ring.
Governor weight.
Retainer for governor weights.
No.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
83.
84.
85.
Description
Thrust sleeve.
Thrust washer.
Drive shaft.
Drive shaft seal.
Drive shaft screw.
Spring washer for screw.
Support washer.
Drive hub.
Drive hub seal.
Quill shaft.
Pump housing.
Gasket for control cover.
Cover-plate.
Gasket for cover-plate.
Screw for cover-plate.
Washer for screw (shakeproof).
Drain connection.
Washer for connection.
Governor arm.
Spring for governor arm.
Keep plate.
Tab washer.
Control bracket.
Screw for bracket.
Tab washer for screw.
Stud for control cover.
Nut for stud.
Washer for stud.
Linkage nut.
Pivot ball washer.
Linkage washer.
Linkage hook.
Linkage spring.
Spring retainer.
Metering valve.
Shut-off bar.
Shut-off Shaft.
Seal for shut-off shaft.
Shut-off lever.
Dust cap for shaft.
Washer for shaft.
Nut for shaft.
No.
86.
87.
88.
89.
90.
91.
92.
93.
94.
95.
96.
97.
98.
99.
100.
101.
102.
103.
104.
105.
106.
107.
108.
109.
110.
111.
112.
113.
114.
115.
116.
117.
118.
119.
120.
121.
122.
123.
124.
125.
126.
127.
Description
Throttle shaft.
Seal for throttle shaft.
Dust cap for shaft.
Nut for shaft.
Throttle arm.
Governor spring.
Guide for idling spring.
Control cover.
Adjusting screw.
Washer for adjusting screw.
Locknut for screw.
Locking sleeve.
Adaptor for sleeve.
Vent screw.
Vent screw body.
Washer for vent screw body.
Adjustment screw for metering valve.
Washer for nut.
Locknut.
Sealing cap.
Automatic advance device housing and piston.
Gasket for housing.
Stud for housing.
Cap nut for stud.
Washer for cap nut.
Cam advance screw.
Piston plug.
Seal for plug.
Piston spring cap.
Seal for cap.
Screw for cap.
Washer for screw.
Head locating bolt.
Slide washer.
Maximum advance stop.
Spring for stop.
Shim washer for spring.
Washer for head locating bolt.
Joint washer for pump mounting flange.
Washer for nut.
Nut for injection pump mounting bolt.
Idling spring.
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