DELIVERY VALVE
FU
NCTl
ON
The delivery valve maintains 300 to
600
psi
(2070
to
4140 kPa) line pressure
in
the injector lines with the
engine running, Figure 31. This pressure increasesto
about 1900 psi (13110 kPa) on each stroke of the
injection pump plunger. The trapped fuel is held
in
the lines at all times, even though the pressure bleeds
off during shutdown periods. When the lines are full of
fuel, onlyacoupleturnsof thecrankshaft are required
to build up enough line pressure for firing the
injectors.
SPRING
DELIVERY VALVE
\
/
.SEAT
.IN€ PRESSURE
DELIVERY VALVE
CAP NUT GASKET
CAP
NUT
\
(Torque
to
55-60
foot-pounds)
FIGURE
32.
DELIVERY VALVE ASSEMBLY
RETURN LINES
UEL RETURN
LINE HERE
(Flexible
Line)
FIGURE
31.
DELIVERY VALVE CLOSED-PLUNGER DOWN
FLOW
TIMING
THE
PSU
PUMP
Flow timing the injection pump can bedone using fuel
to determine whether or not the proper timing button
has been installed for best operating conditions. In
case the pump is removed without recording the PC
dimension and the timing button thickness, it is
necessary to flow time the pump to establish the exact
PC position.
1.
Install
No.
12 timing button in PSU pump as
previously discussed under preparation for pump
installation.
Remove delivery valve cap and holder; take out
spring and replace holder and cap, Figure
32.
2. Remove door panel, air cleaner, and top sheet
metal cover for access to flywheel marks and fuel
system.
3.
Remove
No.
1
injector line; re-install line with top
end of line in pump outlet
so
other end will direct
fuel flow into an open container, Figure 33.
FIGURE
33.
FUEL LINES TO INJECTORS
4.
Place container under open end of
No.
1 line.
5.
Disconnect governor linkage at ball joint and
wedge control arm at maximum fuel position.
6.
Rotate flywheel counterclockwise (when facing
front of engine) to point where PC mark on
flywheel is about 15 degrees before timing pointer
(compression stroke
No.
1
cylinder).
Check that front cyllnder valve rocker arms (both valves) are
free
to move lndlcatlng the valves are closed.
7.
Manually operate fuel transfer pump until air-free
fuel flows steady from end of
No.
1 line into
container.
27
To Next Page
Loading...
Need help?
General
