Hydraulic Valve Tappet; Camshaft Installation (8-Cylinder) - Jeep 1979 CJ-5 Technical & Service Manual

ENGINES 1B-45
K E Y
L D R I V E GEAR
SCREW
7 0 4 5 1
Fig. 1B-71
Camshaft D r i f t Gear
Camshaft installation
(1) Lubricate entire camshaft generously with Jeep
Engine Oil Supplement (EOS), or equivalent.
(2) Carefully install camshaft into engine block.
(3) Assemble timing chain, crankshaft sprocket and
camshaft sprocket with timing marks aligned. Refer to
Timing Chain Installation.
(4) Install oil slinger on crankshaft.
(5) Install fuel pump eccentric and distributor drive
gear to camshaft (fig. 1B-72). Tighten retaining screw to
30 foot-pounds (41 N«m) torque.
NOTE: The fuel pump eccentric has the word "REAR "
stamped on it to indicate proper installed position. The
camshaft screw washer fits into a recess in the distribu-
tor drive gear.
(6) Install replacement timing case cover gasket.
(7) Install timing case cover.
(8) Install replacement oil seal. Apply light film of
engine oil to lips of seal.
(9) Install vibration damper.
(10) Install damper pulley and retaining screws.
Tighten screws to 30 foot-pounds (41 N*m) torque.
(11) Install hydraulic valve tappets lubricated with
Jeep Engine Oil Supplement, or equivalent.
NOTE: Do not drain the EOS from the engine for at
least 1,000 miles (1 609 km) or until the next scheduled
oil change.
(12) Install intake manifold assembly.
(13) Install push rods.
(14) Install rocker arms and bridged pivot assem-
blies. At each bridged pivot, tighten capscrews alter-
nately, one turn at a time, to avoid damaging bridge.
Tighten capscrews to 19 foot-pounds (26 N«m) torque.
(15) Reseal and install cylinder head covers.
(16) Install fuel pump.
(17) Rotate crankshaft until No. 1 piston is at TDC
position on compression stroke.
NOTE: After No. 1 intake valve has closed, TDC can be
reached by rotating the crank clockwise as viewed from
the front until the timing mark on the damper aligns
with TDC on the timing case cover.
(18) Install distributor so that rotor is aligned with
No. 1 terminal of cap when fully seated on block.
(19) Install distributor cap.
(20) Install ignition wires.
(21) If removed, install air conditioning condenser
and receiver assembly.
CAUTION: Both service valves must be open before
the air conditioning system is operated.
(22) Install hood latch support bracket, front bumper
or grille, if removed.
(23) Install radiator.
(24) Fill cooling system to specified level.
• (25) Install and tighten drive belts to proper tension.
Refer to Chapter 1C.
Hydraulic Valve Tappets
The hydraulic valve tappet consists of a tappet body,
plunger, plunger return spring, check valve assembly,
metering disc, plunger cap and lockring (fig. 1B-72).
The tappet operates in a guide bore which has an oil
passage drilled into the adjoining oil gallery.
The operating mode of the hydraulic tappet begins
when the tappet is on the heel of the cam lobe (engine
valve closed). A groove in the tappet body aligns with
the tappet oil gallery, admitting pressurized oil into the
tappet (fig. 1B-73). A hole and groove arrangement ad-
mits the oil to the inside of the plunger. Oil is forced past
the plunger check valve and fills the chamber between
the plunger and tappet body. When the chamber is full,
additional oil in the plunger body unseats the metering
disc, and a spurt of oil flows up the pushrod to lubricate
the rocker assembly. These events all take place while
the tappet is on the heel of the cam lobe. As the cam
turns, the lobe begins exerting force on the tappet body.
This force is transmitted by the trapped oil in the tappet
chamber to the plunger and finally to the pushrod and
rocker assembly. The engine valve opens. While the
valve is open, the trapped oil is subjected to considerable
pressure and some of it escapes between the plunger and
the tappet body (leak-down). The cycle is completed as
the cam lobe rotates back to the starting position and
another charging cycle begins. In this way, zero valve
lash is maintained.
Removal
(1) Remove cylinder head cover.
(2) Remove rocker arms and bridged pivot assem-
blies. Remove two capscrews at each bridged pivot. Al-
ternately loosen capscrews one turn at a time to avoid
damaging bridge.
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