Jeep J-10 Series 1982 Technical & Service Manual page 143

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 with replace
ment gasket.
(13) Install push rods.
(14) Install rocker arms and bridge and pivot assem
blies. Tighten capscrews alternately, one turn at a time,
to avoid damaging bridge. Tighten capscrews with 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, TDCcan be
attained by rotating the crankshaft clockwise as viewed
from the front until the timing mark on the vibration
damper aligns with the TDC index on the timing degree
scale.
(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 conditioner 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) Install fan and hub assembly.
(25) Fill cooling system to specified level.
(26) Install and adjust drive belts to proper tension.
Refer to Chapter 1C—Cooling Systems for procedures.
HYDRAULIC VALVE TAPPETS
A hydraulic valve tappet consists of a tappet body,
plunger, plunger return spring, check valve assembly,
metering disc, plunger cap and lockring (fig. 1B-113).
The tappet operates in a guide bore that 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 (base circle) 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-114). A hole and groove ar
rangement admits the oil to the inside of the plunger. Oil
is forced past the plunger check valve and fills the cham
ber between the plunger and tappet body. When the
chamber is full, additional oil in the plunger body un
seats the metering disc, and a spurt of oil flows up the
pushrod to lubricate the rocker arm 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
ENGINES 1B-75
force on the tappet body. This force is transferred by the
trapped oil in the tappet chamber to the plunger and
finally to the pushrod and rocker arm 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 and
engine noise is reduced.
snapring
plunger cap
metering v a l v e
TAPPET
BODY
CHECK
VALVE
SEAT
CHECK VALVE
CHECK
VALVE
SPRING
CHECK
VALVE
RETAINER
PLUNGER
RETURN
SPRING
42811
Fig. 1B-113 Hydraulic Tippet Assembly
Removal
(1) Remove cylinder head cover.
(2) Remove bridge and pivot assemblies and rocker
arms. Alternately loosen capscrews, one turn at a time,
to avoid damaging bridge.
(3) Remove push rods.
NOTE: Retain bridge and pivot assemblies, rocker
arms and push rods in the same order as removed.
(4) Remove intake manifold.
(5) Remove tappet from guide bore in engine block
with Tool J-21884.