Chrysler Pacifica. Manual — part 698
VALVE SPRINGS
DESCRIPTION
There are two interchangeable, floating (spring
rotates during operation), valve spring designs. Type
A may be identified by the counterclockwise (spring
spirals down and to the left) appearance, And Type B
may be identified by the clockwise (spring spirals
down and to the right) appearance. Both of the valve
springs are a bee-hive shaped design but have differ-
ent specifications (Fig. 49).
The springs are seated on a steel washer on the
cylinder head with retainers and locks retaining the
springs (Fig. 50). The springs are installed with the
smaller diameter against spring retainer (Fig. 49).
OPERATION
The valve spring returns the valve against its seat
for a positive seal of the combustion chamber.
Fig. 49 VALVE SPRING
1 - VALVE SPRING (TOP - SMALLER DIAMETER)
Fig. 50 VALVE COMPONENTS
1 - VALVE LOCKS
5 - SPRING SEATS
2 - RETAINERS
6 - CYLINDER HEAD
3 - VALVE SPRINGS
7 - VALVE - EXHAUST
4 - VALVE STEM SEALS
8 - VALVE - INTAKE
CS
ENGINE 3.8L
9 - 147
REMOVAL
REMOVAL - CYLINDER HEAD OFF
(1) With the cylinder head on a bench, position
Special Tool C-3422-D with 8464 Adapter on the
valve and spring retainer (Fig. 51).
(2) Compress the spring only enough to remove the
valve retainer locks.
(3) Slowly release the spring tension and remove
the valve spring and retainer.
(4) For removal of the valve stem seal (Refer to 9 -
ENGINE/CYLINDER HEAD/VALVE STEM SEALS -
REMOVAL).
REMOVAL - CYLINDER HEAD ON
(1) Disconnect negative cable from battery.
(2) Remove spark plug wires and all spark plugs.
(3) Remove cylinder head cover(s). (Refer to 9 -
ENGINE/CYLINDER
HEAD/CYLINDER
HEAD
COVER(S) - REMOVAL)
(4) Remove rocker arms and shaft. (Refer to 9 -
ENGINE/CYLINDER
HEAD/ROCKER
ARMS
-
REMOVAL)
(5) Rotate engine until the piston in the cylinder
bore requiring spring removal is at TDC.
(6) Install Special Tool 8453 to the cylinder head
(Fig. 52). Tighten the attaching bolts to 23 N·m (200
in. lbs.).
(7) Install a spark plug adapter in the spark plug
hole. Connect air hose that can supply 620.5–689 kPa
(90–100 psi) of air pressure to adapter. This is to
hold valves in place while servicing components.
(8) Locate the forcing screw and spring retainer
adapter assembly over the spring requiring removal
(Fig. 52).
(9) Slowly turn the forcing screw clockwise (com-
pressing the valve spring) until the valve keepers can
be removed.
(10) Turn forcing screw counterclockwise to relieve
spring tension. Remove retainer and valve spring.
(11) Repeat procedure for each cylinder requiring
valve spring removal.
Fig. 51 VALVE SPRING - REMOVE/INSTALL
1 - SPECIAL TOOL C-3422-D SPRING COMPRESSOR
2 - SPECIAL TOOL 8464 ADAPTER
Fig. 52 VALVE SPRING - REMOVE/INSTALL (HEAD
ON)
1 - SPECIAL TOOL 8453
2 - BOLTS - SPECIAL TOOL ATTACHING
3 - AIR SUPPLY HOSE ADAPTER
9 - 148
ENGINE 3.8L
CS
VALVE SPRINGS (Continued)
INSPECTION
NOTE: The are two different types of valve springs
used that are interchangable, but have different
specifications (Refer to 9 - ENGINE/CYLINDER
HEAD/VALVE SPRINGS - DESCRIPTION).
Whenever valves have been removed for inspection,
reconditioning or replacement, valve springs should
be tested (Fig. 53). As an example; the compression
length of a spring to be tested is 38.00 mm (1.496
in.). Turn the table of Tool C-647 until surface is in
line with the 38.00 mm (1.496 in.) mark on the
threaded stud and the zero mark on the front. Place
spring over stud on the table and lift compressing
lever to set tone device. Pull on torque wrench until
ping is heard. Take reading on torque wrench at this
instant. Multiply this reading by two. This will give
the spring load at test length. Fractional measure-
ments are indicated on the table for finer adjust-
ments. Refer to Engine Specifications to obtain
specified height and allowable tensions (Refer to 9 -
ENGINE - SPECIFICATIONS). Replace any springs
that do not meet specifications.
INSTALLATION
INSTALLATION - CYLINDER HEAD OFF
(1) If removed, install a new valve stem seal (Refer
to 9 - ENGINE/CYLINDER HEAD/VALVE STEM
SEALS - INSTALLATION).
(2) Position valve spring and retainer on spring
seat.
(3) Using Special Tool C-3422-D with 8464 Adapter
(Fig. 54), compress the spring only enough to install
the valve retainer locks. Install valve retainer locks.
(4) Slowly release the spring tension. Ensure the
retainer locks are seated properly (Fig. 55).
Fig. 53 Testing Valve Spring
1 - SPECIAL TOOL C-647
Fig. 54 VALVE SPRING COMPRESSOR
1 - SPECIAL TOOL C-3422-D SPRING COMPRESSOR
2 - SPECIAL TOOL 8464 ADAPTER
Fig. 55 VALVE SPRING INSTALLED
1 - VALVE SPRING RETAINER
2 - VALVE INSTALLED HEIGHT
3 - CYLINDER HEAD SURFACE
4 - VALVE SPRING SEAT SURFACE
5 - VALVE SPRING INSTALLED HEIGHT
CS
ENGINE 3.8L
9 - 149
VALVE SPRINGS (Continued)
INSTALLATION - CYLINDER HEAD ON
(1) The intake valve stem seals should be pushed
firmly and squarely over the valve guide using the
valve stem as guide. Do Not Force seal against top
of guide. When installing the valve retainer locks,
compress the spring only enough to install the locks
(Fig. 56).
CAUTION: Do not pinch seal between retainer and
top of valve guide.
(2) Follow the same procedure on the remaining 5
cylinders using the firing sequence 1-2-3-4-5-6. Make
sure piston in cylinder is at TDC on the valve
spring that is being covered.
(3) Remove spark plug adapter tool.
(4) Install rocker arms and shaft assembly. (Refer
to 9 - ENGINE/CYLINDER HEAD/ROCKER ARMS -
INSTALLATION)
(5) Install cylinder head covers. (Refer to 9 -
ENGINE/CYLINDER
HEAD/CYLINDER
HEAD
COVER(S) - INSTALLATION)
(6) Install spark plugs and connect wires.
(7) Connect negative cable to battery.
ROCKER ARMS
DESCRIPTION
DESCRIPTION - ROCKER ARMS
The rocker arms are installed on the rocker arm
shaft. The rocker arms and shaft assembly is
attached to the cylinder head with seven billeted
bolts and retainers. The rocker arms are made of
stamped steel.
PUSHRODS
The pushrods are made of steel and are a hollow
design. The pushrods are positioned between the
hydraulic lifter and the rocker arm.
OPERATION
OPERATION - ROCKER ARMS
The rocker arm pivots are on the rocker shaft.
Rocker arms are used to translate up and down
motions provided by the camshaft, hydraulic roller
lifter, and pushrod on one end, into a down and up
motions on the valve stem on the opposing end.
OPERATION - PUSHRODS
The pushrod is a solid link between the hydraulic
roller lifter and the rocker arm. Also, the pushrod
supplies engine oil from the hydraulic lifter to the
rocker arm.
REMOVAL
ROCKER ARMS AND SHAFT
(1) Remove the cylinder head cover(s). (Refer to 9 -
ENGINE/CYLINDER
HEAD/CYLINDER
HEAD
COVER(S) - REMOVAL)
NOTE: Rocker arm shaft bolts are captured to the
shaft.
(2) Loosen the rocker shaft bolts (Fig. 57), rotating
one turn each, until all valve spring pressure is
relieved.
(3) Remove the rocker arms and shaft assembly
(Fig. 57).
Fig. 56 VALVE SPRING - REMOVE/INSTALL (HEAD
ON)
1 - SPECIAL TOOL 8453
2 - BOLTS - SPECIAL TOOL ATTACHING
3 - AIR SUPPLY HOSE ADAPTER
Fig. 57 ROCKER ARMS AND SHAFT
1 - ROCKER ARMS AND SHAFT ASSEMBLY
2 - ROCKER SHAFT BOLTS
9 - 150
ENGINE 3.8L
CS
VALVE SPRINGS (Continued)
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