Chevrolet 70 Series 1970 Service Manual page 448

Figure 3—Inspection for Broken or Stuck Piston Rings ITypicalI
When an engine is run out of fuel inadvertently,
there is a definite procedure to follow for re sta rt­
ing the engine. The procedure is outlined below:
1. F ill the fuel tank with the recom mended
grade of fuel o il. If only partial fillin g of the tank is
p o ssib le , add a minimum of ten gallons of fuel.
2. Remove the prim ary fuel strainer sh ell and
elem ent from the stra in er cover and fill the sh ell
with fuel o il. Install the sh e ll and elem ent.
3. Rem ove and fill the secondary fuel filter
sh ell and elem ent with fuel o il as in Step 2.
4. Start the engine. Checkthe filter and strain ­
er for leak s.
NOTE: In som e in stan ces, it may be n ecessa ry
to rem ove a valve rocker cover and loosen a fuel
pipe nut in order to bleed trapped air from the fuel
sy ste m . B e su re the fuel pipe is retightened s e ­
curely before replacing the rocker cover.
P rim er (J-5956) may be used to prim e the
entire fuel sy stem . Rem ove the filter plug in the
fu el filte r cover and in stall the p rim er. P rim e the
sy ste m . Rem ove the p rim er and in stall the filter
plug.
FUEL FLOW TEST (Fig. 4)
1. D isconnect the fuel return tube and hold
the open end in a suitable container.
2. Start and run the engine at approxim ately
rpm and m easure the fuel flow from the r e ­
1 2 0 0
turn tube for one minute.
NOTE: At le a st gallons of fuel on 53 S er ies
.6
and .9 gallons on 71 S e r ie s engine should flow
from the return lin e p er minute.
3. B e sure a ll line connections between the
fuel supply and the pump are tight so no air w ill be
drawn into the fuel system ; then, im m erse the end
of the fuel return line into the fuel in the container.
53 AND 71 SERIES DIESEL ENGINES 6C-51
Figure 4 —Fuel Flow Test
A ir bubbles risin g to the surface of the fuel w ill
indicate a leak on the suction side of the pump.
FUEL QUALITY
The quality of the fuel oil used for d ie sel en­
gine operation is a major factor in satisfactory
engine perform ance and life . The fuel o ils selec te d
must be clean, com pletely d istilled , stable, and
n on-corrosive. E nlist the aid of your supplier in
obtaining proper fuel o il. The responsibility for
clean fuel lin es with the fuel supplier as w ell as
with the operator.
DISTILLATION RANGE, CETANE NUMBER,
AND SULFUR CONTENT a re three of the most
important properties in the selectio n of d iesel
fu els for optimum combustion and minimum w ear.
Engine speed, load, and atm ospheric tem perature
influence the selectio n of the fu els with resp ect to
distillation range and cetane number. THE SUL­
FUR CONTENT OF THE FUEL MUST BE AS LOW
AS POSSIBLE, to avoid e x c e ssiv e deposit formation
and prem ature w ear.
FUEL PRESSURE TEST
The fuel p ressu re gauge is designed for u se in
checking fuel p r e ssu re at the in jector with the
engine in operation. Rem ove the jumper line from
the injector to the return fuel manifold and connect
the fuel gauge in p lace of the jumper line (fig. 5).
R efer to "Fuel P ressu re" chart following:
FUEL PRESSURE
SPEED (RPM)
1800
Engine
1 2 0 0
6V-53
6-71 30-65 45-70
8V-71 45-70 45-70
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL
2600
2 1 0 0 2 2 0 0
45-70 45-70
45-70
45-70