Chrysler Town, Dodge Caravan. Manual — part 322
NOTE: Replace cylinder head if stem-to-guide clear-
ance exceeds specifications, or if guide is loose in
cylinder head.
INSTALLATION
(1) Coat valve stems with clean engine oil and
insert them in cylinder head.
(2) Install valve spring seat on head (Fig. 35).
(3) Install new seals on all valve stems and over
valve guides (Fig. 35). Install valve springs and valve
retainers (Fig. 35).
(4) Install
the
valve
springs.
(Refer
to
9
-
ENGINE/CYLINDER
HEAD/VALVE
SPRINGS
-
INSTALLATION)
VALVE SPRINGS
DESCRIPTION
The valve springs are a bee-hive shaped design
(Fig. 34). The springs are seated on a steel washer on
the cylinder head with retainers and locks retaining
the springs (Fig. 35). The springs are installed with
the smaller diameter against spring retainer (Fig.
34).
OPERATION
The valve spring returns the valve against its seat
for a positive seal of the combustion chamber.
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. 36).
(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.
Fig. 32 Intake and Exhaust Valves
1 - MARGIN
2 - FACE
3 - STEM
4 - VALVE SPRING RETAINER LOCK GROOVES
Fig. 33 Measuring Valve Guide Wear - Typical
Fig. 34 Valve Spring
1 - VALVE SPRING (TOP - SMALLER DIAMETER)
9 - 106
ENGINE 3.3/3.8L
RS
INTAKE/EXHAUST VALVES & SEATS (Continued)
(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. 37). 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. 37).
(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.
Fig. 35 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
Fig. 36 VALVE SPRING - REMOVE/INSTALL
1 - SPECIAL TOOL C-3422-D SPRING COMPRESSOR
2 - SPECIAL TOOL 8464 ADAPTER
RS
ENGINE 3.3/3.8L
9 - 107
VALVE SPRINGS (Continued)
(11) Repeat procedure for each cylinder requiring
valve spring removal.
INSPECTION
Whenever valves have been removed for inspection,
reconditioning or replacement, valve springs should
be tested (Fig. 38). 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. 36), 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.
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.
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.
Fig. 37 VALVE SPRING - REMOVE/INSTALL (HEAD
ON)
1 - SPECIAL TOOL 8453
2 - BOLTS - SPECIAL TOOL ATTACHING
3 - AIR SUPPLY HOSE ADAPTER
Fig. 38 TESTING VALVE SPRING
1 - SPECIAL TOOL C-647
9 - 108
ENGINE 3.3/3.8L
RS
VALVE SPRINGS (Continued)
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 bolts and
retainers. The rocker arms are made of stamped
steel.
DESCRIPTION - 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 on the rocker shaft. Rocker
arms are used to translate up and down motions pro-
vided by the camshaft, hydraulic 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
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. 39), rotating
one turn each, until all valve spring pressure is
relieved.
(3) Remove the rocker arms and shaft assembly
(Fig. 39).
(4) For rocker arm disassembly procedures, (Refer
to 9 - ENGINE/CYLINDER HEAD/ROCKER ARMS -
DISASSEMBLY).
DISASSEMBLY - ROCKER ARMS AND SHAFT
CAUTION: Do not attempt to drive the bolt from the
rocker shaft. This can damage the retainer and bolt
assembly.
(1) Remove the rocker arm retainer and bolt by
performing the following procedure:
(a) Using adjustable pliers, grip the edges of the
retainer (Fig. 40).
(b) Apply an upward force with a slight rocking
motion until the retainer disengages from shaft
(Fig. 40).
(2) Remove rocker arms (Fig. 41). Identify the
component locations for reassembly in original loca-
tions.
ASSEMBLY - ROCKER ARMS AND SHAFT
(1) Install rocker arms on the shaft (Fig. 41).
Install in the orginal positions if re-used. Ensure the
rocker shaft, all the retainers and washers are prop-
erly positioned and installed in the correct locations
(Fig. 41).
(2) Install rocker arms and shaft to the cylinder
head. (Refer to 9 - ENGINE/CYLINDER HEAD/
ROCKER ARMS - INSTALLATION)
Fig. 39 ROCKER ARMS AND SHAFT
1 - ROCKER ARMS AND SHAFT ASSEMBLY
2 - ROCKER SHAFT BOLTS
RS
ENGINE 3.3/3.8L
9 - 109
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