Ford COUGAR 1968 Shop Manual page 343

PART'8-3
-
289 And 302 V-8
TO AUTOMATIC CHOKE
FIG. 6-Automatic Choke Heat
Chamber
IMCO ENGINE
289 AND 302
V-8
FIG. 3-Front Cross Sectional View
- -
.
RIGHT BANK
+ FRONT
-
FIG. 4-Intake Manifold Exhaust
Gas
Crossover Passage
inder block. An eccentric, bolted to
the front end of the camshaft, opera-
tes the fuel pump.
Two different types of hydraulic
valve lifters, (Figs. 8 and 9) are used
on all other 289 and 302 V-8 engines.
These lifters provide zero valve lash
and operate on the same principle.
Although the valve lifter assem-
blies are interchangeable, or both
may be used, on the same engine.
the component parts are not inter-
changeable. The valve lifters are
easily identified, type 11 having three
circumferential ribs on the barrel
near the oil hole. On type I1 design
lifter, an upper metering valve retain-
er with tensioning finger is used,
whereas in type I the metering valve
is flat.
1 , 4 , 6 , A N D 7
0
2, 3, 5, AND
8
,
A1 5 7 9 4
FIG. 5-Typical Intake Manifold
Fuel Passages
When the valve is closed, the lifter
assembly is on the base circle of the
camshaft lobe and the valve push
rod is in its lowest position. With the
lifter assembly in this position, the
FIG. 7-Valve Port Arrangement
plunger spring expands, forcing the
plunger upward. This action is trans-
mitted to the valve rocker arm via
the valve push rod until there is solid
contact between the valve and the
valve end of the valve rocker arm
(zero valve lash).
As the lifter plunger moves up-
ward, the volume of the compression
chamber is increased, resulting in re-
duced oil pressure in the compression
chamber. Therefore, to equalize the
resulting pressure differential be-
tween the snpply chamber and the
compression chamber, the check
valve moves off its seat and permits
oil to flow from the supply chamber
to the compression chamber. When
the compression chamber becomes
filled with oil, the pressures in the
two chambers are equalized. The oil
flow ceases and the check valve spring
seats the check valve and closes the
check valve port.
As the camshaft rotates, the lifter
assembly is raised by the camshaft