Jeep Wrangler TJ. Manual — part 444
(1) If a replacement cover is installed, transfer the
CCV valve grommet and oil filler cap from the origi-
nal cover to the replacement cover.
(2) Install cylinder head cover and gasket (Fig. 14).
Tighten the mounting bolts to 10 N·m (85 in. lbs.)
torque.
(3) Reinstall the plastic wiring loom trough at the
rear of cylinder head cover.
(4) Reconnect the left hand side of the wiring har-
ness loom to all components.
(5) Connect the CCV hoses.
(6) Install control cables and bracket on intake
manifold and tighten bolts to 8.7 N·m (77 in. lbs.)
torque.
(7) Connect control cables to throttle body linkage.
(8) Snap control cables into cylinder head cover
clip.
(9) Connect negative cable to battery.
INTAKE/EXHAUST VALVES &
SEATS
DESCRIPTION
The valves are made of heat resistant steel and
have chrome plated stems to prevent scuffing. All
valves use three bead locks to promote valve rotation
(Fig. 15).
STANDARD PROCEDURE - VALVE SERVICE
VALVE REFACING
Clean all carbon deposits from the combustion
chambers, valve ports, valve stems, valve stem
guides and head.
(1) Use a valve refacing machine to reface the
intake and exhaust valves to the specified angle.
(2) After refacing, a margin of at least 0.787 mm
(0.031 inch) must remain (Fig. 16). If the margin is
less than 0.787 mm (0.031 inch), the valve must be
replaced.
VALVE SEAT REFACING
Clean all carbon deposits from the combustion
chambers, valve ports, valve stems, valve stem
guides and head.
(1) Install a pilot of the correct size in the valve
guide bore. Reface the valve seat to the specified
Fig. 14 Cylinder Head Cover Gasket Locator Pins at
#8 & #9
Fig. 15 VALVE AND KEEPER CONFIGURATION 4.0L
1 - VALVE LOCKS (3–BEAD)
2 - RETAINER
3 - VALVE STEM OIL SEAL
4 - INTAKE VALVE
5 - EXHAUST VALVE
6 - VALVE SPRING
Fig. 16 Valve Facing
1 - VALVE MARGIN
2 - NO MARGIN
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ENGINE 4.0L
9 - 91
CYLINDER HEAD COVER(S) (Continued)
angle with a good dressing stone. Remove only
enough metal to provide a smooth finish.
(2) Use tapered stones to obtain the specified seat
width when required.
(3) Control valve seat runout to a maximum of
0.0635 mm (0.0025 in.) (Fig. 17).
VALVE STEM-TO-GUIDE CLEARANCE
MEASUREMENT
PREFERRED METHOD
(1) Remove the valve from the head.
(2) Clean the valve stem guide bore with solvent
and a bristle brush.
(3) Insert a telescoping gauge into the valve stem
guide bore approximately 9.525 mm (.375 inch) from
the valve spring side of the head (Fig. 18).
(4) Remove and measure telescoping gauge with a
micrometer.
(5) Repeat the measurement with contacts length-
wise to engine cylinder head.
(6) Compare the crosswise to lengthwise measure-
ments to determine out-of-roundness. If the measure-
ments differ by more than 0.0635 mm (0.0025 in.),
ream the guide bore to accommodate an oversize
valve stem.
(7) Compare the measured valve guide bore diam-
eter with specifications (7.95-7.97 mm or 0.313-0.314
inch). If the measurement differs from specification
by more than 0.076 mm (0.003 inch), ream the guide
bore to accommodate an oversize valve stem.
ALTERNATIVE METHOD
(1) Use a dial indicator to measure the lateral
movement of the valve stem (stem-to-guide clear-
ance). This must be done with the valve installed in
its guide and just off the valve seat (Fig. 19).
(2) Correct
clearance
is
0.025-0.0762
mm
(0.001-0.003 inch). If indicated movement exceeds the
specification ream the valve guide to accommodate
an oversize valve stem.
NOTE: Valve seats must be ground after reaming
the valve guides to ensure that the valve seat is
concentric to the valve guide.
Fig. 17 Measurement of Valve Seat Runout
1 - DIAL INDICATOR
Fig. 18 Measurement of Valve Guide Bore Diameter
1 - GAUGE
2 - 9.525 MM (3/8 INCH)
3 - VALVE STEM GUIDE
4 - CYLINDER HEAD
Fig. 19 Measurement of Lateral Movement Of Valve
Stem
1 - DIAL INDICATOR
9 - 92
ENGINE 4.0L
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INTAKE/EXHAUST VALVES & SEATS (Continued)
REMOVAL
NOTE: This procedure is done with the engine cyl-
inder head removed from the block.
(1) Remove the engine cylinder head (Refer to 9 -
ENGINE/CYLINDER HEAD - REMOVAL) from the
cylinder block.
(2) Use
Valve
Spring
Compressor
Tool
MD-998772A and compress each valve spring.
(3) Remove the valve locks, retainers, springs and
valve stem oil seals. Discard the oil seals (Fig. 20).
(4) Use a smooth stone or a jewelers file to remove
any burrs on the top of the valve stem, especially
around the groove for the locks.
(5) Remove the valves, and place them in a rack in
the same order as removed.
INSTALLATION
NOTE: This procedure is done with the engine cyl-
inder head removed from the block.
(1) Thoroughly clean the valve stems and the valve
guide bores.
(2) Lightly lubricate the stem.
(3) Install the valve in the original valve guide
bore.
(4) Install the replacement valve stem oil seals on
the valve stems (Fig. 21). If the 0.381 mm (0.015
inch) oversize valve stems are used, oversize oil seals
are required.
(5) Position the valve spring and retainer on the
engine cylinder head and compress the valve spring
with Valve Spring Compressor Tool MD-998772A.
(6) Install the valve locks and release the tool.
(7) Tap the valve spring from side to side with a
hammer to ensure that the spring is properly seated
at the engine cylinder head. Also tap the top of the
retainer to seat the valve locks.
(8) Install the engine cylinder head (Refer to 9 -
ENGINE/CYLINDER HEAD - INSTALLATION).
Fig. 20 Valve and Valve Components
1 - VALVE LOCKS (3–BEAD)
2 - RETAINER
3 - VALVE STEM OIL SEAL
4 - INTAKE VALVE
5 - EXHAUST VALVE
6 - VALVE SPRING
Fig. 21 Valve and Valve Components
1 - VALVE LOCKS (3–BEAD)
2 - RETAINER
3 - VALVE STEM OIL SEAL
4 - INTAKE VALVE
5 - EXHAUST VALVE
6 - VALVE SPRING
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ENGINE 4.0L
9 - 93
INTAKE/EXHAUST VALVES & SEATS (Continued)
ROCKER ARM / ADJUSTER
ASSEMBLY
DESCRIPTION
The rocker arms are made of stamped steel and
have a operational ratio of 1.6:1 (Fig. 22).
OPERATION
When the push rods are forced upward by the cam-
shaft lobes the push rod presses upward on the
rocker arms, the rocker arms pivot, forcing down-
ward pressure on the valves forcing the valves to
move downward and off from their seats.
REMOVAL
NOTE: This procedure can be done with the engine
in or out of the vehicle.
(1) Remove the cylinder head cover (Refer to 9 -
ENGINE/CYLINDER
HEAD/CYLINDER
HEAD
COVER(S) - REMOVAL).
(2) Check for rocker arm bridges which are caus-
ing misalignment of the rocker arm to valve tip area.
(3) Remove the capscrews at each bridge and pivot
assembly (Fig. 23). Alternately loosen the capscrews
one turn at a time to avoid damaging the bridges.
(4) Remove the bridges, pivots and corresponding
pairs of rocker arms (Fig. 23). Place them on a bench
in the same order as removed.
(5) Remove the push rods and place them on a
bench in the same order as removed.
CLEANING
Clean all the components with cleaning solvent.
Use compressed air to blow out the oil passages in
the rocker arms and push rods.
INSPECTION
Inspect the pivot surface area of each rocker arm.
Replace any that are scuffed, pitted, cracked or
excessively worn.
Inspect the valve stem tip contact surface of each
rocker arm and replace any rocker arm that is deeply
pitted.
Inspect each push rod end for excessive wear and
replace as required. If any push rod is excessively
worn because of lack of oil, replace it and inspect the
corresponding hydraulic tappet for excessive wear.
Inspect the push rods for straightness by rolling
them on a flat surface or by shining a light between
the push rod and the flat surface.
A wear pattern along the length of the push rod is
not normal. Inspect the engine cylinder head for
obstruction if this condition exists.
Fig. 22 Rocker Arms—Typical
1 - CAPSCREWS
2 - BRIDGE
3 - PIVOT ASSEMBLY
4 - PUSH RODS
5 - ROCKER ARMS
Fig. 23 Rocker Arm
1 - CAPSCREWS
2 - BRIDGE
3 - PIVOT ASSEMBLY
4 - PUSH RODS
5 - ROCKER ARMS
9 - 94
ENGINE 4.0L
TJ
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