Dodge Dakota (R1). Manual — part 474
INSPECTION
Inspect all surfaces with a straightedge if there is
any reason to suspect leakage. If out-of-flatness
exceeds
0.00075mm/mm
(0.0001in./in.)
times
the
span length in any direction, either replace head or
lightly machine the head surface.
FOR EXAMPLE:—A 305 mm (12 in.) span is
0.102 mm (0.004 in.) out-of-flat. The allowable out-of-
flat is 305 x 0.00075 (12 x 0.00075) equals 0.23 mm
(0.009 in.). This amount of out-of-flat is acceptable.
The
cylinder
head
surface
finish
should
be
1.78-3.00 microns (70-125 microinches).
Inspect push rods. Replace worn or bent rods.
INSTALLATION
The alloy cast iron cylinder heads (Fig. 8) are held
in place by eight bolts. The spark plugs are located
at the peak of the wedge between the valves.
(1) Position the new cylinder head gaskets onto
the cylinder block.
(2) Position the cylinder heads onto head gaskets
and cylinder block.
(3) Starting at top center, tighten all cylinder head
bolts, in sequence, to 68 N·m (50 ft. lbs.) torque (Fig.
8). Repeat procedure, tighten all cylinder head bolts
to 143 N·m (105 ft. lbs.) torque. Repeat procedure to
confirm that all bolts are at 143 N·m (105 ft. lbs.)
torque.
CAUTION: When tightening the rocker arm bolts, be
sure the piston in that cylinder is NOT at TDC. Con-
tact between the valves and piston could occur.
(4) Install push rods and rocker arm assemblies in
their original positions. Tighten the bolts to 28 N·m
(21 ft. lbs.) torque.
(5) Install the intake manifold (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE
MANIFOLD
-
INSTALLATION) and throttle body assembly.
(6) Install
exhaust
manifolds
(Refer
to
9
-
ENGINE/MANIFOLDS/EXHAUST
MANIFOLD
-
INSTALLATION).
(7) Adjust spark plugs to specifications. Install the
plugs and tighten to 41 N·m (30 ft. lbs.) torque.
(8) Install coil wires.
(9) Connect coolant temperature sending unit wire.
(10) Connect the fuel injector harness.
(11) Connect the vacuum supply hoses to the
intake manifold.
(12) Connect the heater hoses and bypass hose.
(13) Install distributor cap and wires.
(14) Connect the accelerator linkage and, if so
equipped, the speed control and transmission kick-
down cables.
(15) Install the fuel supply line.
(16) Install the generator and accessory drive belt
(Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE
BELTS
-
INSTALLATION).
Tighten
generator
mounting bolt to 41 N·m (30 ft. lbs.) torque.
(17) Install
the
intake
manifold-to-generator
bracket support rod. Tighten the bolts.
(18) Install cylinder head covers. (Refer to 9 -
ENGINE/CYLINDER
HEAD/CYLINDER
HEAD
COVER(S) - INSTALLATION).
(19) Install closed crankcase ventilation system.
(20) Connect the evaporation control system.
(21) Install the resonator assembly, air in-let hose
and air cleaner.
(22) Install the heat shields. Tighten the bolts to
41 N·m (30 ft. lbs.) torque.
(23) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(24) Connect the battery negative cable.
CYLINDER HEAD COVER(S)
DESCRIPTION—CYLINDER HEAD COVER
GASKET
The cylinder head cover gasket (Fig. 9) is a steel-
backed silicone gasket, designed for long life usage.
REMOVAL
A steel-backed silicone gasket is used with the cyl-
inder head cover (Fig. 10). This gasket can be used
again.
(1) Disconnect the negative cable from the battery.
(2) Disconnect closed ventilation system and evap-
oration control system from cylinder head cover.
(3) Remove cylinder head cover bolts, cover and
gasket. The gasket may be used again.
CLEANING
Clean cylinder head cover gasket surface.
Clean head rail, if necessary.
Fig. 8 Cylinder Head Bolt -Tightening Sequence
9 - 84
ENGINE 3.9L
AN
CYLINDER HEAD (Continued)
INSPECTION
Inspect cover for distortion and straighten, if nec-
essary.
Check the gasket for use in head cover installation.
If damaged, use a new gasket.
INSTALLATION
A steel-backed silicone gasket is used with the cyl-
inder head cover (Fig. 10) . This gasket can be used
again.
(1) Position the cylinder head cover gasket onto
the head rail.
(2) Position the cylinder head cover onto the gas-
ket and install the bolts. Tighten the bolts to 11 N·m
(95 in. lbs.) torque.
(3) Install closed crankcase ventilation system and
evaporation control system.
(4) Connect the negative cable to the battery.
(5) Start engine and check for leaks.
INTAKE/EXHAUST VALVES &
SEATS
DESCRIPTION
Both the intake and exhaust valves are made of
steel. The intake valve is 48.768 mm (1.92 inches) in
diameter and the exhaust valve is 41.148 mm (1.62
inches) in diameter and has a 2.032 mm (0.080 inch)
wafer interia welded to the tip for durability. These
valves are not splayed.
STANDARD PROCEDURE—VALVES, GUIDES
AND SPRINGS
VALVE CLEANING
Clean valves thoroughly. Discard burned, warped,
or cracked valves.
Remove carbon and varnish deposits from inside of
valve guides with a reliable guide cleaner.
VALVE GUIDES
Measure valve stems for wear. If wear exceeds
0.051 mm (0.002 in.), replace the valve.
Measure valve stem guide clearance as follows:
(1) Install Valve Guide Sleeve Tool C-3973 over
valve stem and install valve (Fig. 11). The special
sleeve places the valve at the correct height for
checking with a dial indicator.
(2) Attach dial indicator Tool C-3339 to cylinder
head and set it at right angles to valve stem being
measured (Fig. 12).
(3) Move valve to and from the indicator. The total
dial indicator reading should not exceed 0.432 mm
(0.017 in.). Ream the guides for valves with oversize
stems if dial indicator reading is excessive or if the
stems are scuffed or scored.
Fig. 9 Cylinder Head Cover Gasket
1 - CYLINDER HEAD COVER GASKET
Fig. 10 Cylinder Head Cover Gasket
1 - CYLINDER HEAD COVER GASKET
Fig. 11 Positioning Valve with Tool C-3973
1 - VALVE
2 - SPACER TOOL
AN
ENGINE 3.9L
9 - 85
CYLINDER HEAD COVER(S) (Continued)
VALVE GUIDES
Service valves with oversize stems are available.
Refer to REAMER SIZES CHART
REAMER SIZES CHART
REAMER O/S
VALVE GUIDE SIZE
0.076 mm
8.026 - 8.052 mm
(0.003 in.)
(0.316 - 0.317 in.)
0.381 mm
8.331 - 8.357 mm
(0.015 in.)
(0.328 - 0.329 in.)
(1) Slowly turn reamer by hand and clean guide
thoroughly before installing new valve. Ream the
valve guides from standard to 0.381 mm (0.015
in.). Use a two step procedure so the valve
guides are reamed true in relation to the valve
seat:
• Step 1—Ream to 0.0763 mm (0.003 inch).
• Step 2—Ream to 0.381 mm (0.015 inch).
REFACING VALVES AND VALVE SEATS
The intake and exhaust valves have a 43-1/4° to
43-3/4° face angle and a 44-1/4° to 44-3/4° seat angle
(Fig. 13).
VALVE FACE AND VALVE SEAT ANGLE CHART
ITEM
DESCRIPTION
SPECIFICATION
A
SEAT WIDTH
INTAKE
1.016 - 1.524 mm
(0.040 - 0.060 in.)
EXHAUST
1.524 - 2.032 mm
(0.060 - 0.080 in.)
B
FACE ANGLE
(INT. AND EXT.)
43¼° - 43¾°
C
SEAT ANGLE
(INT. AND EXT.)
44¼° - 44¾°
D
CONTACT
SURFACE
—
Fig. 12 Measuring Valve Guide Wear
1 - VALVE
2 - SPECIAL TOOL C-3339
Fig. 13 Valve Face and Seat Angles
1 - CONTACT POINT
A,B,C and D Refer to VALVE FACE AND VALVE SEAT ANGLE
CHART
9 - 86
ENGINE 3.9L
AN
INTAKE/EXHAUST VALVES & SEATS (Continued)
VALVES
Inspect the remaining margin after the valves are
refaced (Fig. 14). Valves with less than 1.190 mm
(0.047 in.) margin should be discarded.
VALVE SEATS
CAUTION: DO NOT un-shroud valves during valve
seat refacing (Fig. 15).
(1) When refacing valve seats, it is important that
the correct size valve guide pilot be used for reseat-
ing stones. A true and complete surface must be
obtained.
(2) Measure the concentricity of valve seat using a
dial indicator. Total runout should not exceed 0.051
mm (0.002 in.) total indicator reading.
(3) Inspect the valve seat with Prussian blue, to
determine where the valve contacts the seat. To do
this, coat valve seat LIGHTLY with Prussian blue
then set valve in place. Rotate the valve with light
pressure. If the blue is transferred to the center of
valve face, contact is satisfactory. If the blue is trans-
ferred to the top edge of valve face, lower valve seat
with a 15° stone. If the blue is transferred to bottom
edge of valve face raise valve seat with a 60° stone.
(4) When seat is properly positioned the width of
intake seats should be 1.016-1.524 mm (0.040-0.060
in.). The width of the exhaust seats should be 1.524-
2.032 mm (0.060-0.080 in.).
VALVE SPRINGS
Whenever valves have been removed for inspection,
reconditioning or replacement, valve springs should
be tested. As an example the compression length of
the spring to be tested is 1-5/16 in.. Turn table of
Universal Valve Spring Tester Tool until surface is in
line with the 1-5/16 in. mark on the threaded stud.
Be sure the zero mark is to the front (Fig. 16). 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 2. This will give the
spring load at test length. Fractional measurements
are indicated on the table for finer adjustments.
Refer to specifications to obtain specified height and
allowable tensions. Discard the springs that do not
meet specifications.
REMOVAL
(1) Remove
the
cylinder
head
(Refer
to
9
-
ENGINE/CYLINDER HEAD - REMOVAL).
(2) Compress valve springs using Valve Spring
Compressor Tool MD- 998772A and adapter 6716A.
(3) Remove valve retaining locks, valve spring
retainers, valve stem seals and valve springs.
(4) Before removing valves, remove any burrs from
valve stem lock grooves to prevent damage to the
valve guides. Identify valves to ensure installation in
original location.
CLEANING
Clean valves thoroughly. Discard burned, warped,
or cracked valves.
Remove carbon and varnish deposits from inside of
valve guides with a reliable guide cleaner.
Fig. 14 Intake and Exhaust Valves
1 - MARGIN
2 - VALVE SPRING RETAINER LOCK GROOVE
3 - STEM
4 - FACE
Fig. 15 Refacing Valve Seats
1 - STONE
2 - PILOT
3 - VALVE SEAT
4 - SHROUD
AN
ENGINE 3.9L
9 - 87
INTAKE/EXHAUST VALVES & SEATS (Continued)
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