DODGE TRUCK 1993 Service Repair Manual
Page 621 of 1502
9 - 16
ENGINES
•
CONDITION
POSSIBLE
CAUSES
CORRECTION
EXCESSIVE
VIBRATION
Loose
or broken engine mounts.
Replace
engine mounts.
Damaged
fan or improperly
operating
accessories.
Check
and replace the vibrating components.
Improperly operating vibration
clamper. Inspect/replace the vibration damper.
Improperly operating fan hub. Inspect/replace the fan hub.
Worn
or
damaged
alternator
bearing.
Check/replace
the alternator.
Flywheel
housing
misaligned. Check/correct flywheel alignment.
Loose
or broken power
component.
Inspect
the crankshaft and rods for damage
that
causes
an
unbalance.
Repair/replace as required.
Worn
or unbalanced driveline
components.
Check/repair driveline components.
EXCESSIVE
ENGINE
NOISES
Drive belt squeal, insufficient
tension
or abnormally high
loading.
Check
the tensioner and inspect the drive belt. Make sure water
pump,
tensioner pulley, fan hub and alternator turn
freely.
Intake air or exhaust leaks. Refer to
Excessive
Exhaust
Smoke
(Engine
Diagnosis—
Performance).
Excessive
valve
lash
Adjust
valves.
Make sure the
push
rods are not bent and rocker
levers or adjusting screws are not severely worn. Replace bent
or
severely worn
pads.
Turbocharger
noise.
Check
turbocharger impeller and turbine wheel for housing
contact. Repair/replace as required.
Gear
train
noise.
Visually
inspect and measure gear
backlash.
Replace gears as
required.
Power
function knock.
Check/replace
rod and main bearings.
ALTERNATOR
NOT
CHARGING
OR IN-
SUFFICIENT
CHARGING
Loose
or corroded battery
connections.
Alternator belt slipping. Clean/tighten battery connection.
Check/replace
belt tensioner. Check/replace belt.
Alternator pulley loose on
shaft.
Tighten pulley.
Improperly operating
alternator.
Check/replace
alternator.
J9109-253
SERVICE DIAGNOSIS (DIESEL ENGINE) - MECHANICAL (CONT.)
Page 622 of 1502
•
3.9L ENGINE
9 - 17
3.9L
ENGINE SERVICE PROCEDURES
INDEX
page
Camshaft
31
Crankshaft
38
Crankshaft Main Bearings
39
Crankshaft Rear
Oil
Seals
. 40
Cylinder Block
41
Cylinder Head Cover
. , 21
Cylinder Heads
. 22
Distributor
33
Engine
Assembly .........................
20
Engine
Front Mounts
17
Engine
Rear Mount
18
Front Crankshaft
Oil
Seal Replacement ........
31
GENERAL INFORMATION
The 3.9 Liter (238 CID) six-cylinder engine is a
V-Type, lightweight, single cam, overhead valve en gine with hydraulic roller tappets (Fig. 1).
Engine
Type
90° V-6 OHV
Bore
and Stroke 99.3
x
84.0 mm (3.91 x3.31
in.)
Displacement 3.9L (238 cu.
in.)
Compression
Ratio
9.1:1
Torque 305 N-m (225
ft.
lbs.)
@
3,200
rpm
Firing Order.... 1-6-5-4-3-2
Lubrication
Pressure
Feed-Full Flow
Filtration
Engine
Oil
Capacity 3.8L (4.0 Qts)
with Filter
Cooling
System
Liquid Cooled-Forced
Circulation
Cooling Capacity 14.3L
(15.1
Qts)
Cylinder Block Cast Iron
Crankshaft Nodular Iron
Cylinder Head
Cast
Iron
Combustion Chambers "Fast
Burn"
Design
Camshaft Nodular
Cast
Iron
Pistons
Aluminum Alloy
w/Strut
Connecting
Rods
Forged Steel
J9309-29
Fig.
1
Engine
Description
This engine is designed for unleaded fuel. Engine lubrication system consists of a rotor type
oil pump and a full flow oil filter.
The cylinders are numbered from front to rear; 1,
3,
5 on the left bank and 2, 4, 6 on the right bank.
The firing order is
1-6-5-4-3-2
(Fig. 2).
The engine serial number is stamped into a ma
chined pad located on the left, front corner of the cyl
inder block. When component part replacement is
necessary, use the engine type and serial number for
reference (Fig. 3).
page
General
Information
17
Hydraulic Tappets
27
Oil
Pan 34
Oil Pump
34
Piston
/
Connecting
Rod
Assembly
36
Rocker
Arms
21
Specifications—3.9L Engine
43
Timing Chain Cover
29
Valve Stem Seal
/
Spring Replacement ........
27
Valve Timing
28
Valves
/
Valve Springs
25
Vibration
Damper
29
J9309-26
Fig.
2 Firing Order i M 3.9L T xxxx
XXXXXXXX
X
=
Last Digit
of
Model Year
M
=
Plant -
M
Mound
Road
S
Sabillo
T Trenton
K
Toluca
3.9L
=
Engine Displacement
T
=
Usage
-
T Truck
XXXX
=
Month/Day
XXXXXXXX
- Serial Code -
Last
8
Digits of
VIN
No.
J9209-72
Fig.
3
Engine
identification
Number
ENGINE FRONT MOUNTS
REMOVAL (1) Disconnect the negative cable from the battery.
Page 623 of 1502
9
- 18 3.9L
ENGINE
• (2) Raise hood and position fan to assure clearance
for radiator top tank and hose.
CAUTION:
DO NOT
lift
the engine by the
intake
manifold.
(3) Install engine lifting fixture.
(4) Raise vehicle on hoist.
(5) Remove bolts and nuts from insulators (Figs. 4
and 5).
ATTACHING
BOLT
ATTACHING
NUT
BRACKET
INSULATOR
ATTACHING
BOLT
FRAME
SIDE
INSULATOR?
(RIGHT
SIDE)
(LEFT
SIDE)
J9109-238
Fig.
4
Engine
Front
Mounts—2WD
Vehicles
ATTACHING
NUT
FRAME
SIDE
INSULATOR
BRACKET
STUD
NUT»
STUD NUT
ATTACHING
BOLT INSULATOR
BACKING.
PLATE
ATTACHING
NUT
BRACKET
STUD NUT
FRONT
BRACKET
STUD NUT
ATTACHING
NUT
FRAME
s,de
(RIGHT
SIDE)
J9109-239
Fig.
5
Engine
Front
Mounts—4WD
Vehicles
(6) Raise engine with lifting fixture only far
enough to remove insulators.
(7) If necessary, remove the bracket from the block
(Figs.
4 and 5).
(8) If necessary, remove the front bracket (4WD)
from the crossmember (Fig. 5).
INSTALLATION (1) If removed, position the front bracket (4WD) to
the crossmember (Fig. 5). Install the attaching nuts and tighten to 41 N»m (30 ft. lbs.) torque. (2) If removed, position the bracket to the block
(Figs.
4 and 5). Install the bolts and tighten to 41
N*m (30 ft. lbs.) torque. (3) With engine raised SLIGHTLY, install insula
tors on front bracket (Figs. 4 and 5).
(4) Lower engine with lifting fixture while guiding
insulator studs into brackets.
(5) Install attaching bolts and nuts (Figs. 4 and 5).
Tighten the attaching bolts and nuts to 41 N«m (30 ft. lbs.) torque,
(6) Install insulator stud nuts and washers.
Tighten the stud nuts to 102 N»m (75 ft. lbs.) torque.
(7) Lower the vehicle.
(8) Remove lifting fixture.
ENGINE
REAR
MOUNT
REMOVAL-2WD (1) Raise the vehicle on a hoist. (2) Position a transmission jack in place.
(3) Remove rear mount insulator through-bolt and
nut (Fig. 6). (4) Raise rear of transmission and engine
SLIGHTLY.
(5) Remove the flange nuts from the frame cross-
member support bracket (Fig. 6). (6) Raise rear of transmission enough to provide
insulator to crossmember clearance. Remove the in sulator and the crossmember support bracket. Re
move the flange nuts and separate the insulator from
the support bracket (Fig. 6).
(7) If necessary, remove the attaching bolts hold
ing the transmission support bracket to the transmis
sion (Fig. 6).
INSTALLA
TION-2WD
(1) If removed, position the transmission support
bracket to the transmission. Install the attaching
bolts and tighten to 68 N*m (50 ft. lbs.) torque.
(2) Position insulator in transmission support
bracket. Install through-bolt.
(3) Be sure insulator is secured in a LEVEL posi
tion relative to transmission rear support bracket.
Tighten the through-bolt nut to 68 N*m (50 ft. lbs.) torque.
(4) Position the crossmember support bracket onto
the insulator (Fig. 6). Install the insulator flange nut(s) and tighten to 41 Nnn (30 ft. lbs.) torque.
(5) Using the transmission jack, lower the insula
tor and crossmember support bracket onto the cross- member (Fig. 6).
(6) Tighten the crossmember flange nuts to 41 Nnn
(30 ft. lbs.) torque.
(7) Remove the transmission jack.
(8) Lower the vehicle.
HE MO
VAL—4
WD (1) Raise the vehicle on a hoist.
Page 624 of 1502
3.9L
ENGINE
9 - 19
INSULATOR
TRANSMISSION
ATTACHING
BOLT
TRANSMISSION
THROUGH
BOLT
TRANSMISSION
SUPPORT
BRACKET
INSULATOR
CROSSMEMBER
SUPPORT BRACKET
CROSSMEMBER
FLANGE NUTS TRANSMISSION
SUPPORT
BRACKET
A
ATTACHING
§^ BOLT
J9109-241
(2) Remove the skid plate (if equipped) from the
rear crossmember and transmission crossmember (Fig. 7). (3) Position transmission jack under transmission
and raise rear
of
transmission and engine
SLIGHTLY.
(4)
AUTOMATIC
TRANSMISSION—Remove
the nuts and bolts holding the transmission support spacer to the insulator mounting plate (Fig. 8). Re
move the bolts and nuts holding the engine rear sup
port plate to the insulator mounting plate (Fig. 8).
(5)
MANUAL
TRANSMISSION—Remove the
nuts and bolts holding the insulator mounting plate
to the transfer case (Fig. 9).
(6) Remove insulator mounting bolts, spacers,
washers and upper/lower insulators (Figs. 8 and 9).
Fig.
6 Rear
Engine
Support—2WD
(7) Remove the insulator mounting plate (Figs. 8
and 9).
TRANSFER CASE
ENGINE
REAR
SUPPORT
PLATE EXTENSION
ASSEMBLY
TRANSMISSION
SUPPORT
SPACER
^——SPACER
fjy.^
UPPER ^INSULATOR
INSULATOR
MOUNTING PLATE
LOWER
INSULATOR
RAIL
ASSEMBLY
J9109-243
PU873
Fig.
8 Rear
Engine
Support—4WD
with
Automatic
Transmission
Fig.
7
Skid
Plate
Page 625 of 1502
TRANSFER
CASE
INSULATOR
MOUNTING PLATE
NUT(B
RAIL
ASSEMBLY
SPACER
UPPER
INSULATOR
NUT®
LOWER
INSULATOR
J9109-242
Fig.
9 Rear
Engine
Support—4WD
with
Manual
Transmission
(8) If necessary, remove the transmission support
spacer (automatic transmission) from the extension
assembly (Fig. 8).
(9) If necessary, remove the engine rear support
plate (automatic transmission) from the transfer case (Fig. 8).
INSTALLATION-4WD
(1) If removed, position the engine rear support
plate (automatic transmission) to the transfer case (Fig. 8). Install the bolts and tighten to 41 N-m (30
ft. lbs.) torque.
(2) If removed, position the transmission support
spacer (automatic transmission) to the extension as
sembly (Fig. 8). Install the bolts and tighten to 68 N-m (50 ft. lbs.) torque.
(3) Install insulator mounting plate, mounting
bolts,
spacers, washers and upper/lower insulators to
the rail assembly (Figs. 8 and 9). Tighten the mount
ing nuts to 204 N*m (150 ft. lbs.) torque.
(4) AUTOMATIC TRANSMISSION-Align the
engine rear support plate and the transmission sup
port spacer to the insulator mounting plate (Fig. 8). Lower the engine and transmission onto the insula
tor mounting plate and install the bolts. Tighten the transmission support spacer nuts to 204 N-m (150 ft. lbs.) torque. Tighten the engine rear support plate
bolts to 41 N-m (30 ft. lbs.) torque.
(5) MANUAL TRANSMISSION—Align the
transfer case to the insulator mounting plate and lower the engine and transmission. Install the bolts and tighten the nuts (Fig. 9 - nut A) to 204 N-m (150 ft. lbs.) torque. Install the bolts and tighten the nuts
(Fig. 9 - nut B) to 41 N-m (30 ft. lbs.) torque. (6) Install the skid plate.
(7) Lower the vehicle.
ENGINE
ASSEMBLY
REMOVAL (1) Scribe hood hinge outlines on hood. Remove the
hood.
(2) Remove the battery. (3) Drain cooling system (refer to Group 7, Cooling
System for the proper procedure).
(4) Remove the air cleaner. (5) Disconnect the radiator and heater hoses. Re
move radiator (refer to Group 7, Cooling System).
(6) Set fan shroud aside. (7) Remove the vacuum lines. (8) Remove the distributor cap and wiring.
(9) Disconnect the accelerator linkage.
(10) Remove MPI throttle body. (11) Disconnect the fuel lines. (12) Disconnect the starter wires.
(13) Disconnect the oil pressure wire. (14) Discharge the air conditioning system, if
equipped (refer to Group 24, Heating and Air Condi
tioning for service procedures). (15) Disconnect the air conditioning hoses.
(16) Disconnect the power steering hoses, if
equipped. (17) Remove starter motor (refer to Group 8B, Bat
tery/Starter/Generator Service). (18) Remove the generator (refer to Group 8B, Bat
tery/Starter/Generator Service).
(19) Raise and support the vehicle on a hoist.
(20) Disconnect exhaust pipe at manifold.
(21) AUTOMATIC TRANSMISSION: (a) Support transmission. This will assure that
the torque converter will remain in proper position in the transmission housing. (b) Remove bell housing bolts and inspection
plate.
(c) Attach a C-clamp on front bottom of trans
mission torque converter housing to prevent torque
converter from falling out.
(d) Remove torque converter drive plate bolts
from torque converter drive plate. Mark converter and drive plate to aid in assembly.
(22) MANUAL TRANSMISSION: (a) Support transmission.
(b) Disconnect clutch release mechanism and re
move transmission to clutch housing bolts.
CAUTION:
DO NOT
lift
the engine by the intake
manifold.
(23) Install an engine lifting fixture.
(24) Remove engine front mount bolts.
Page 626 of 1502
•
3.9L
ENGINE
9 - 21 (25) Lower the vehicle.
(26) On automatic transmission vehicles, discon
nect the engine from the torque converter drive
plate. On manual transmission vehicles, move engine forward until drive pinion shaft clears the clutch
disc.
Remove engine from engine compartment. (27) Install engine assembly on engine repair
stand.
INSTALLATION (1) Remove engine from the repair stand and posi
tion in the engine compartment.
(2) Install engine support fixture.
(3) Raise and support the vehicle on a hoist.
(4)
AUTOMATIC TRANSMISSION: (a) Position the torque converter and drive plate.
Install torque converter drive plate bolts. Tighten
the bolts to 31 Nnn (270 in. lbs.) torque.
(b) Install the engine front mounts.
(c) Install bell housing bolts. Tighten the bolts to
41 N-m (30 ft. lbs.) torque.
(d) Remove C-clamp.
(e) Install the inspection plate.
(5) MANUAL TRANSMISSION: (a) Position the drive pinion shaft to the clutch
disc.
(b) Connect the clutch release mechanism and
install the transmission to clutch bolts. Tighten the
bolts to 68 N-m (50 ft. lbs.) torque.
(c) Install the engine front mounts.
(6) Remove transmission support.
(7) Install exhaust pipe to manifold.
(8) Lower the vehicle.
(9) Remove engine lifting fixture.
(10) Install the generator (refer to Group 8B, Bat
tery/Starter/Generator Service). (11) Install starter motor (refer to Group 8B, Bat
tery/Starter/Generator Service). (12) Connect power steering hoses, if equipped.
(13) Connect air conditioning hoses.
(14) Evacuate and charge the air conditioning sys
tem, if equipped (refer to Group 24, Heater and Air Conditioning for service procedures). (15) Using a new gasket, install MPI throttle body.
Tighten the throttle body bolts to 23 N-m (200 in. lbs.) torque. (16) Connect the accelerator linkage.
(17) Connect the starter wires. (18) Connect the oil pressure wire.
(19) Install the distributor cap and wiring.
(20) Connect the vacuum lines.
(21) Connect the fuel lines.
(22) Install the radiator (refer to Group 7, Cooling
System). Connect the radiator hoses and heater
hoses.
(23) Install fan shroud in position. (24) Fill cooling system (refer to Group 7, Cooling
System for the proper procedures). (25) Install the air cleaner.
(26) Install the battery.
(27) Warm engine and adjust.
(28) Install hood and line up with the scribe
marks. (29) Road test vehicle.
CYLINDER
HEAD COVER
A steel backed silicon gasket is used with the cyl
inder head cover (Fig. 1). This gasket can be used again.
CYLINDER HEAD COVER GASKET
J9209-104
Fig.
1 Cylinder Head
Cover
Gasket
REMOVAL (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 and gasket. The
gasket may be used again.
CLEANING Clean cylinder head cover gasket surface. Clean head rail, if necessary.
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 (1) The cylinder head cover gasket can be used
again. Install the gasket onto the head rail.
(2) Position the cylinder head cover onto the gas
ket. 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.
ROCKER
ARMS
REMOVAL (1) Disconnect spark plug wires by pulling on the
boot straight out in line with plug.
(2) Remove cylinder head cover and gasket.
Page 627 of 1502
(3) Remove the rocker arm bolts and pivots (Fig.
2).
Place them on a bench in the same order as re
moved.
(4) Remove the push rods and place them on a
bench in the same order as removed.
ROCKER
ARMS
J9209-66
Fig.
2
Rocker Arms
INSTALLATION
(1) Rotate the crankshaft until the "V6" mark
lines up with the TDC mark on the timing chain
case cover. This mark is located 147° ATDC from the
No.l firing position.
CAUTION:
DO NOT
rotate
or
crank
the
engine dur
ing
or
immediately
after
rocker
arm
installation.
Al
low
the
hydraulic roller tappets adequate time
to
bleed down (about
5
minutes).
(2) Install the push rods in the same order as re
moved.
(3) Install rocker arm and pivot assemblies in the
same order as removed. Tighten the rocker arm bolts
to 28 N*m (21 ft. lbs.) torque.
(4) Install cylinder head cover.
(5) Connect spark plug wires.
CYLINDER
HEADS
The alloy cast iron cylinder heads (Fig. 3) are held
in place by 8 bolts. The spark plugs are located in
the peak of the wedge between the valves.
REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Drain cooling system (refer to Group 7, Cooling
System for the proper procedures). (3) Remove the heat shields (Fig. 4).
SPARK SPARK
INTAKE
PLUGS
PLUG VALVE
EXHAUST INTAKE EXHAUST VALVE VALVES VALVES
J9309-35
Fig.
3 Cylinder Head
Assembly Fig.
4
Exhaust
Manifold Heat
Shields
(4) Remove the intake manifold-to-generator
bracket support rod. Remove the generator.
(5) Remove closed crankcase ventilation system.
(6) Disconnect the evaporation control system.
(7) Remove the air cleaner.
(8) Disconnect the fuel lines.
(9) Disconnect accelerator linkage and if so
equipped, the speed control and transmission kick-
down cables. (10) Remove the return spring.
(11) Remove distributor cap and wires.
(12) Disconnect the coil wires.
(13) Disconnect heat indicator sending unit wire.
(14) Disconnect heater hoses and bypass hose.
(15) Remove cylinder head covers and gaskets.
(16) Remove intake manifold and throttle body as
an assembly. Discard the flange side gaskets and the
front and rear cross-over gaskets.
(17) Remove exhaust manifolds.
(18) Remove rocker arm assemblies and push rods.
Identify to ensure installation in original locations.
Page 628 of 1502
•
3.9L
ENGINE
9 - 23 (19) Remove the head bolts from each cylinder
head and remove cylinder heads. Discard the cylin der head gasket.
(20) Remove spark plugs.
CLEANING
Clean all surfaces of cylinder block and cylinder
heads.
Clean cylinder block front and rear gasket surfaces
using a suitable solvent.
INSPECTION
Inspect all surfaces with a straightedge if there is
any reason to suspect leakage. If out-of-flatness ex
ceeds 0.00075 mm/mm (0.00075 inch/inch) times the
span length in any direction, either replace head or
lightly machine the head surface.
FOR EXAMPLE:—A 305 mm (12 inch) span is
0.102 mm (0.004 inch) out-of-flat. The allowable out-
of-flat is 305 x 0,00075 (12 x 0.00075) equals 0.23
mm (0.009 inch). This amount of out-of-flat is accept
able.
The cylinder head surface finish should be 1.78-
3.00 microns (70-125 microinches). Inspect push rods. Replace worn or bent rods.
INSTALLATION
(1) Apply Perfect Sealant No.5, or equivalent, to
both sides of the gasket (Fig. 5).
PERFECT
SEALANT
NO.
5
PERFECT
SEALANT
NO.
5
Fig.
5 Sealant Location on Cylinder Head
Gasket
(2) Position the new cylinder head gaskets onto the
cylinder block.
(3) Position the cylinder heads onto head gaskets
and cylinder block.
(4) Starting at top center, tighten all cylinder head
bolts,
in sequence, to 68 N»m (50 ft. lbs.) torque (Fig.
6).
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,
Fig.
6 Cylinder Head
Bolt
Tightening
Sequence
make
sure
the
piston
in
that
cylinder is NOT at
TDC.
Contact
between the
valves
and
piston
could
occur.
(5) Install push rods and rocker arm assemblies in
their original position. Tighten the bolts to 28 Nnn (21 ft. lbs.) torque.
(6) Place the 4 plastic locator dowels into the holes
in the block Fig. 7). (7) Apply Mopar Silicone Rubber Adhesive Seal
ant, or equivalent, to the four corner joints. An ex
cessive amount of sealant is not required to ensure a
leak proof seal. However, an excessive amount of sealant may reduce the effectiveness of the flange
gasket. The sealant should be slightly higher than
the cross-over gaskets, approx. 5 mm (0.2 in).
(8) Install the front and rear cross-over gaskets
onto the dowels (Fig. 7).
FRONT
CROSS-OVER
GASKET
REAR
CROSS-OVER
GASKET
J9209-99
Fig.
7
Cross-Over
Gaskets
and Locator
Dowels
Page 629 of 1502
(9) Install the flange gaskets. Be sure that the ver
tical port alignment tab is resting on the deck face of
the block. Also the horizontal alignment tabs must
be in position with the mating cylinder head gasket
tabs (Fig. 8). The words MANIFOLD SIDE should be
visible on the center of each flange gasket.
FLANGE GASKET
INTAKE
AAANIFOLD
CYLINDER
HEAD GASKET
J9209-101
Fig.
8 Intake Manifold Flange
Gasket
Alignment
(10) Carefully lower intake manifold into position
on the cylinder block and cylinder heads. Use the alignment dowels in the cross-over gaskets to posi
tion the intake manifold. After intake manifold is in
place, inspect to make sure seals are in place.
(11) The following torque sequence duplicates the
expected results of the automated assembly system
(Fig. 9).
• Step
1-Tighten
bolts 1 and 2 to 8 N-m (72 in. lbs.)
torque. Tighten in alternating steps 1.4 N-m (12 in. lbs.) torque at a time.
• Step 2—Tighten bolts 3 through 12, in sequence,
to 8 N-m (72 in. lbs.) torque.
• Step 3—Check that all bolts are tighten to 8 N-m (72 in. lbs.) torque.
• Step 4—Tighten all bolts, in sequence, to 16 N-m (12 ft. lbs.) torque.
• Step 5—Check that all bolts are tighten to 16 N-m (12 ft. lbs.) torque. (12) Install exhaust manifolds. Tighten the bolts
and nuts to 34 N-m (25 ft. lbs.) torque.
FRONT OF ENGINE
J9209-59
Fig.
9 Intake Manifold
Bolt
Tightening
Sequence
(13) Adjust spark plugs to specifications (refer to
Group 8D, Ignition System). Install the plugs and
tighten to 41 N-m (30 ft. lbs.) torque.
(14) Install coil wires. (15) Connect heat indicator sending unit wire.
(16) Connect the heater hoses and bypass hose.
(17) Install distributor cap and wires.
(18) Hook up the return spring.
(19) Connect the accelerator linkage and if so
equipped, the speed control and transmission kick-
down cables.
(20) Install the fuel lines.
(21) Install the generator and drive belt. Tighten
generator mounting bolt to 41 N-m (30 ft. lbs.)
torque. Tighten the adjusting strap bolt to 23 N-m (200 in. lbs.) torque. Refer to Group 7, Cooling Sys
tem for adjusting the belt tension. (22) Install the intake manifold-to-generator
bracket support rod. Tighten the bolts. (23) Place the cylinder head cover gaskets in posi
tion and install cylinder head covers. Tighten the
bolts to 11 N-m (95 in. lbs.) torque.
(24) Install closed crankcase ventilation system.
(25) Connect the evaporation control system.
(26) Install the air cleaner.
(27) Install the heat shields. Tighten the bolts to
41 N-m (30 ft. lbs.) torque. (28) Fill cooling system (refer to Group 7, Cooling
System for proper procedure). (29) Connect the negative cable to the battery.
Page 630 of 1502
•
3.9L
ENGINE
9 - 25
VALVES
/
VALVE
SPRINGS
The valves are arranged in-line and inclined 18°.
The rocker pivot support and the valve guides are cast integral with the heads. This procedure requires the removal of the cylinder
head.
REMOVAL
(1) Remove the cylinder head.
(2) Compress valve springs using Valve Spring
Compressor Tool MD-998772A.
(3) Remove valve retaining locks, valve spring re
tainers, 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.
VALVE
CLEANING
Clean valves thoroughly. Discard burned, warped
and cracked valves.
Remove carbon and varnish deposits from inside of
valve guides with a reliable guide cleaner.
VALVE
INSPECTION
Measure valve stems for wear. If wear exceeds
0.051 mm (0.002 inch), replace the valve. Measure valve stem guide clearance as follows:
(a) Install Valve Guide Sleeve Tool C-3973 over
valve stem and install valve (Fig. 10). The special sleeve places the valve at the correct height for
checking with a dial indicator.
Fig.
10 Positioning Valve with Tool C-3973
(b) Attach dial indicator Tool C-3339 to cylinder
head and set it at right angle of valve stem being
measured (Fig. 11).
(c) Move valve to and from the indicator. The to
tal dial indicator reading should not exceed 0.432
mm (0.017 inch). Ream the guides for valves with
oversize stems if dial indicator reading is excessive
or if the stems are scuffed or scored.
Service valves with oversize stems are available
(Fig. 12).
Slowly turn reamer by hand and clean guide thor
oughly before installing new valve. Ream the valve
guides from standard to 0.381 mm (0,015 inch).
Fig.
11 Measuring Valve Guide Wear
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.)
J9309-30
Fig.
12
Reamer
Sizes
Use a 2 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
/
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).
VAL¥ES
Inspect the remaining margin after the valves are
refaced (Fig. 14). Valves with less than 1.190 mm (0.047 inch) 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 ob
tained.
(2) Measure the concentricity of valve seat using a
dial indicator. Total runout should not exceed 0.051
mm (0.002 inch) total indicator reading.