Engine Systems
necessary, add clean fuel oil at the inlet filter until it
runs out the outlet filter.
Do not tighten the injector clamp bolt to more than
20-25 lb-ft (27 -34 Nm) torque, as this may cause the
moving parts of the injector to bind. Tighten the
rocker shaft bolts to 90-100 lb-ft (122-136 Nm)
torque.
Align the fuel pipes and connect them to the injector
and the fuel connectors. Use socket J 8932-01 and a
torque wrench to tighten the fuel pipe nuts to 12-15
lb-ft (16-20 Nm) torque.
CAUTION: Do not bend the fuel pipes and do
not exceed the specified torque. Excessive
tightening will twist or fracture the flared ends
of the fuel pipes and result in leaks.
Lubricating oil diluted by fuel oil can cause
serious damage to the engine bearings.
Fig. 2 - Removing Injector from Cylinder Head
Time the injector, position the injector rack control
lever and adjust the exhaust valve clearance (cold
CAUTION: If a wrench is used on the crankshaft
setting) as outlined in the engine tune-up procedure.
bolt at the front of the engine, do not turn the
If all of the injectors have been replaced, perform a
crankshaft in a left-hand direction of rotation
complete tune-up on the engine.
as the bolt may be loosened. Either remove the
starting motor or the pipe plug in the flywheel
housing and use a pry bar against the teeth of
Fuel Pump
the flywheel ring gear to turn the crankshaft.
A positive displacement gear type fuel pump is
5. Remove the two rocker shaft bracket bolts and
attached to the blower and driven off the front end of
swing the rocker arm assembly away from the injector
the blower.
and valves.
A spring-loaded relief valve, incorporated in the
6. Remove the injector clamp bolt, washer and clamp.
pump body, normally remains in the closed position,
operating only when the pressure on the outlet side (to
7. Loosen the inner and outer adjusting screws on the
the fuel filter) becomes excessive due to a plugged
injector rack control lever and slide the lever away
filter or fuel line.
from the injector.
The fuel pump incorporates two oil seals. Two tapped
8. Free the injector from its seat as shown in Fig. 2
holes are provided in the underside of the pump body
and lift it from the cylinder head.
to permit draining off any leakage of oil.. If fuel
leakage exceeds one drop per minute, the seals must
9. Cover the injector hole in the cylinder head to keep
be replaced. An authorized Detroit Diesel Allison
foreign particles out of the cylinder.
Service Outlet is properly equipped to replace the seals.
The fuel pump used on the V-71 engines is a left-
hand rotating pump. Regardless of engine rotation,
Install Injector
the pump will always rotate in a left-hand direction.
Before installing an injector, be sure the beveled seat
of the injector tube is free from dirt particles and
carbon deposits.
Fuel Strainer and Fuel Filter
A replaceable element type fuel strainer and fuel filter
A new or reconditioned injector may be installed by
(Figs. 1 and 3) are used in the fuel system to remove
reversing the sequence of operations given for
impurities from the fuel. The strainer removes the
removal.
larger foreign particles and the filter removes the
small foreign particles.
Be sure the fuel injector is filled with fuel oil. If
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