Perkins 4.108 Workshop Manual page 82

AIR CLEANERS AND FUEL SYSTEM-N.S
of the circlip, it denotes commencement of injection
(static timing) see Fig, N,16.
To set the timing circlip, it is necessary to remove the
pump from the engine and fix the position of the cir-
clip by connecting No. 1 cylinder outlet connection
(marked W) to an atomiser tester and pump up to 30
atm (31 kgflcm2) or 440 Ibflin 2 . Turn the pump by
hand in the normal direction of rotation until it "locks
up". The squared end of the circlip should now be
lined up with the letter A (for hydraulically governed
pumps) or C (for mechanically governed pumps) on
the pump rotor.
NOTE: On earlier pumps, the timing circlip had a
scribed line on one end and on these pumps, the
scribed line on the fuel pump rotor should be aligned
with the scribed line on the circlip.
N16
1. Ensure the pump circlip is correctly positioned as
previously described and that the fuel pump is cor-
rectly fitted to the engine with the scribed line on
the mounting flange aligning with the adjacent
mounting flange on the cylinder block (see Fig.
N.11) .
2. Position the crankshaft so that No. 1 piston is at
T.O.C. on its compression stroke.
3. Remove the cylinder head cover.
4. Slacken the valve adjusting screw No. 1 exhaust
valve sufficiently to allow the rocker lever to be
moved to one side and the push rod removed,
rotate the rocker lever on the shaft so that the
valve spring cap is accessible for using the valve
spring compressor.
5. Remove the collets, spring cap and springs from
No.1 exhaust valve and allow the valve to'rest on
the top of the piston. A suitable ring should be
fitted to the valve stem to prevent the valve falling
completely into the cylinder.
6, With the aid of a clock gauge in contact with the
end of the valve now resting on No. 1 piston, it
will be necessary to position the crankshaft so
that the piston will be 0.108 in (2,75 mm) B.T.D.C.
this being the equivalent of 18
C
on the engine fly-
wheel. Refer Fig. N.17.
To do this, zero the gauge to piston T.O.C. and
then turn the crankshaft in the opposite direction
turn and then forward until the required position
is registered on the clock gauge. This enables
the backlash in the timing gears to be taken up.
NOTE: The above setting is for 4.108 vehicle
engines. For other applications and engines see
Page B.12.
7. Remove the inspection plate on the fuel pump
enabling the rotor to be seen. (Fig. N.16).
8. With No. 1 piston at the static timing point on its
compression stroke, the scribed line on the rotor
marked
'A'
(for hydraulically governed engines) or
'c'
(for mechanically governed engines) should
align with the straight edge or scribed line on the
timing circlip.
9. If the timing is incorrect proceed by either:-
(a) making any necessary adjustments by means
of the holes in the fuel pump gear, they are
slotted enabling the drive shaft to be turned
relative to the gear when the securing set-
screws are slackened. (Refer to Fig. J.6) or
(b) by slackening the two nuts and socket headed
setscrew which secure the fuel pump to the
mounting flange and turning the pump body
in the direction required.
10. When the fuel pump timing has been set, turn the
engine against the normal direction of rotation
once again to the appropriate piston displacement
to check that the squared end of the circlip is now
aligned with the line on the rotor.
11. When the fuel pump tmiing has been correctly set,
slowly turn the engine to T.O.C. in the normal
direction of rotation, remove the clock gauge and
refit the valve springs.
12. Refit the push rod and reset the valve clearance.
to normal rotation, approximately an eight of a
Ni7