Valve DODGE RAM 2001 Service Manual PDF

DESCRIPTION SPECIFICATION
End Play None
Length 75.946 - 76.454 mm
(2.990 - 3.010 in.)
PISTON RINGS
Ring Gap
Compression Rings 0.254 - 0.508 mm
(0.010 - 0.020 in.)
Oil Control (Steel Rails) 0.254 - 1.270 mm
(0.010 - 0.050 in.)
Ring Side Clearance
Compression Rings 0.038 - 0.076 mm
(0.0015 - 0.0030 in.)
Oil Control (Steel Rails) 0.06 - 0.21 mm
(0.002 - 0.008 in.)
Ring Width
Compression Rings 1.971 - 1.989 mm
(0.0776 - 0.0783 in.)
Oil Control (Steel Rails) 3.848 - 3.975 mm
(0.1515 - 0.1565 in.)
VALVE TIMING
Exhaust Valve
Closes 16É (ATDC)
Opens 52É (BBDC)
Duration 248É
Intake Valve
Closes 50É (ABDC)
Opens 10É (BTDC)
Duration 240É
Valve Overlap 26ÉOVERSIZE AND UNDERSIZE ENGINE
COMPONENT MARKINGS CHART
OS-US Item Identification Location of
Identification
U/S Crankshaft R or M M-2-3
ect.Milled flat on
.0254
MM(indicating No.
2&No. eight
(.001
IN.)3 main
bearingcrankshaft
journal) and/or counterweight.
R-1-4 ect.
(indicating No.
1&
4 connecting
rod
journal)
O/S TappetsL3/89
.2032
mmdiamound
(.008 in.) -shaped
stamp Top
pad
Ð Front of
engine and
flat
ground on
outside
surface
of each O/S
tappet bore.
O/S Valve
StemsX Milled pad
.127 mm adjacent to
two
(0.005
in.)3/89tapped
holes on
each
end of
cylinder
head.
BR/BEENGINE 3.9L 9 - 17
ENGINE 3.9L (Continued)

SPECIAL TOOLS
ENGINEÐ3.9L
Oil Pressure Gauge C-3292
Engine Support Fixture C-3487±A
Valve Spring Compressor MD-998772±A
Adapter 6633
Adapter 6716A
Valve Guide Sleeve C-3973
Dial Indicator C-3339
Puller C-3688
Front Oil Seal Installer 6635
Camshaft Holder C-3509
BR/BEENGINE 3.9L 9 - 19
ENGINE 3.9L (Continued)

CYLINDER HEAD
DESCRIPTIONÐCYLINDER HEAD
The cast iron cylinder heads (Fig. 5) are mounted
to the cylinder block using eight bolts. The spark
plugs are located in the peak of the wedge between
the valves.
DESCRIPTIONÐCYLINDER HEAD COVER
GASKET
The cylinder head cover gasket (Fig. 6) is a steel-
backed silicone gasket, designed for long life usage.
OPERATIONÐCYLINDER HEAD
The cylinder head closes the combustion chamber
allowing the pistons to compress the air fuel mixture to
the correct ratio for ignition. The valves located in the
cylinder head open and close to either allow clean air
into the combustion chamber or to allow the exhaust
gases out, depending on the stroke of the engine.
OPERATIONÐCYLINDER HEAD COVER
GASKET
The steel-backed silicone gasket is designed to seal
the cylinder head cover for long periods of time
through extensive heat and cold, without failure. The
gasket is designed to be reusable.
DIAGNOSIS AND TESTINGÐCYLINDER HEAD
GASKET FAILURE
A cylinder head gasket leak can be located between
adjacent cylinders or between a cylinder and the
adjacent water jacket.
²Possible indications of the cylinder head gasket
leaking between adjacent cylinders are:
²Loss of engine power
²Engine misfiring
²Poor fuel economy
²Possible indications of the cylinder head gasket
leaking between a cylinder and an adjacent water
jacket are:
²Engine overheating
²Loss of coolant
²Excessive steam (white smoke) emitting from
exhaust
²Coolant foaming
CYLINDER-TO-CYLINDER LEAKAGE TEST
To determine if an engine cylinder head gasket is
leaking between adjacent cylinders, follow the proce-
dures in Cylinder Compression Pressure Test in this
section. An engine cylinder head gasket leaking
between adjacent cylinders will result in approxi-
mately a 50±70% reduction in compression pressure.
CYLINDER-TO-WATER JACKET LEAKAGE TEST
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING WITH COOLANT PRES-
SURE CAP REMOVED.
VISUAL TEST METHOD
With the engine cool, remove the coolant pressure
cap. Start the engine and allow it to warm up until
thermostat opens.
If a large combustion/compression pressure leak
exists, bubbles will be visible in the coolant.
Fig. 5 Cylinder Head AssemblyÐ3.9L Engine
1 - SPARK PLUGS
2 - SPARK PLUG
3 - INTAKE VALVE
4 - EXHAUST VALVES
5 - INTAKE VALVES
6 - EXHAUST VALVE
Fig. 6 Cylinder Head Cover Gasket
1 - CYLINDER HEAD COVER GASKET
9 - 22 ENGINE 3.9LBR/BE

COOLING SYSTEM TESTER METHOD
WARNING: WITH COOLING SYSTEM TESTER IN
PLACE, PRESSURE WILL BUILD UP FAST. EXCES-
SIVE PRESSURE BUILT UP, BY CONTINUOUS
ENGINE OPERATION, MUST BE RELEASED TO A
SAFE PRESSURE POINT. NEVER PERMIT PRES-
SURE TO EXCEED 138 kPa (20 psi).
Install Cooling System Tester 7700 or equivalent to
pressure cap neck. Start the engine and observe the
tester's pressure gauge. If gauge pulsates with every
power stroke of a cylinder a combustion pressure
leak is evident.
CHEMICAL TEST METHOD
Combustion leaks into the cooling system can also
be checked by using Bloc-Chek Kit C-3685-A or
equivalent. Perform test following the procedures
supplied with the tool kit.
REMOVAL
The alloy cast iron cylinder heads (Fig. 7) are held
in place by eight bolts. The spark plugs are located
at the peak of the wedge between the valves.
(1) Disconnect the battery negative cable from the
battery.
(2) Drain cooling system. (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(3) Remove the intake manifold-to-generator
bracket support rod. Remove the generator.
(4) Remove closed crankcase ventilation system.
(5) Disconnect the evaporation control system.
(6) Remove the air cleaner, air in-let hose and res-
onator.
(7) Perform fuel system pressure release procedure
(Refer to 14 - FUEL SYSTEM/FUEL DELIVERY -
STANDARD PROCEDURE).
(8) Disconnect the fuel supply line from the fuel
rail (Refer to 14 - FUEL SYSTEM/FUEL DELIVERY/
QUICK CONNECT FITTING - STANDARD PROCE-
DURE).
(9) Disconnect accelerator linkage and if so
equipped, the speed control and transmission kick-
down cables.
(10) Remove distributor cap and wires.
(11) Disconnect the coil wires.
(12) Disconnect coolant temperature sending unit
wire.
(13) Disconnect heater hoses and bypass hose.
(14) Disconnect the vacuum supply hoses from the
intake manifold.
(15) Disconnect the fuel injector harness and
secure out of the way.
(16) Remove cylinder head covers and gaskets
(Refer to 9 - ENGINE/CYLINDER HEAD/CYLIN-
DER HEAD COVER(S) - REMOVAL).(17) Remove intake manifold and throttle body as
an assembly. Discard the flange side gaskets and the
front and rear cross-over gaskets.
(18) Remove exhaust manifolds (Refer to 9 -
ENGINE/MANIFOLDS/EXHAUST MANIFOLD -
REMOVAL).
(19) Remove rocker arm assemblies and push rods.
Identify to ensure installation in original locations.
(20) Remove the head bolts from each cylinder
head and remove cylinder heads. Discard the cylin-
der head gasket.
(21) 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
exceeds 0.00075mm (0.0001in.) times the span length
in any direction, either replace head or lightly
machine the head surface.
FOR EXAMPLE:ÐA 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. 7) 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.
7). 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.
BR/BEENGINE 3.9L 9 - 23
CYLINDER HEAD (Continued)

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 PROCEDUREÐVALVES, 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. 9). 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. 10).
(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.
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:
²Step 1ÐReam to 0.0763 mm (0.003 inch).
²Step 2ÐReam to 0.381 mm (0.015 inch).
Fig. 9 Positioning Valve with Tool C-3973
1 - VALVE
2 - SPACER TOOL
Fig. 10 Measuring Valve Guide Wear
1 - VALVE
2 - SPECIAL TOOL C-3339
BR/BEENGINE 3.9L 9 - 25

REFACING VALVES AND VALVE SEATS
The intake and exhaust valves have a 43-1/4É to
43-3/4É face angle and a 44-1/4É to 44-3/4É seat angle
(Fig. 11).
VALVE FACE AND VALVE SEAT ANGLE CHART
ITEM DESCRIPTION SPECIFICATION
ASEAT WIDTH
INTAKE 1.016 - 1.524 mm
(0.040 - 0.060 in.)
EXHAUST 1.524 - 2.032 mm
(0.060 - 0.080 in.)
BFACE ANGLE
(INT. AND EXT.) 43òÉ - 43ôÉ
CSEAT ANGLE
(INT. AND EXT.) 44òÉ - 44ôÉ
DCONTACT
SURFACE Ð
VALVES
Inspect the remaining margin after the valves are
refaced (Fig. 12). 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. 13).
Fig. 11 Valve Face and Seat Angles
1 - CONTACT POINT
A,B,C and D Refer to VALVE FACE AND VALVE SEAT ANGLE
CHART
Fig. 12 Intake and Exhaust Valves
1 - MARGIN
2 - VALVE SPRING RETAINER LOCK GROOVE
3 - STEM
4-FACE
Fig. 13 Refacing Valve Seats
1-STONE
2 - PILOT
3 - VALVE SEAT
4 - SHROUD
9 - 26 ENGINE 3.9LBR/BE
INTAKE/EXHAUST VALVES & SEATS (Continued)

(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 15É stone. If the blue is transferred to bottom
edge of valve face raise valve seat with a 60É 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. 14). 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.
INSPECTION
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. 15). 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. 16).
(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. 14 Testing Valve Spring for Compressed
Length
1 - TORQUE WRENCH
2 - VALVE SPRING TESTER
Fig. 15 Positioning Valve with Tool C-3973
1 - VALVE
2 - SPACER TOOL
BR/BEENGINE 3.9L 9 - 27
INTAKE/EXHAUST VALVES & SEATS (Continued)

INSTALLATION
(1) Clean valves thoroughly. Discard burned,
warped and cracked valves.
(2) Remove carbon and varnish deposits from
inside of valve guides with a reliable guide cleaner.
(3) Measure valve stems for wear. If wear exceeds
0.051 mm (0.002 inch), replace the valve.
(4) Coat valve stems with lubrication oil and insert
them in cylinder head.
(5) If valves or seats are reground, check valve
stem height. If valve is too long, replace cylinder
head.
(6) Install new seals on all valve guides. Install
valve springs and valve retainers.
(7) Compress valve springs with Valve Spring
Compressor Tool MD-998772A and adapter 6716A,
install locks and release tool. If valves and/or seats
are ground, measure the installed height of springs.
Make sure the measurement is taken from bottom of
spring seat in cylinder head to the bottom surface of
spring retainer. If spacers are installed, measure
from the top of spacer. If height is greater than 42.86
mm (1-11/16 inches), install a 1.587 mm (1/16 inch)
spacer in head counterbore. This should bring spring
height back to normal 41.27 to 42.86 mm (1-5/8 to
1-11/16 inch).
(8) Install cylinder head (Refer to 9 - ENGINE/
CYLINDER HEAD - INSTALLATION).
ENGINE BLOCK
CLEANING
Clean cylinder block thoroughly and check all core
hole plugs for evidence of leakage.
INSPECTION
Examine block for cracks or fractures.
The cylinder walls should be checked for out-of-
round and taper. Refer to Honing Cylinder Bores in
the Service Procedures portion of this Section.
Inspect the oil line plug, the oil line plug is located
in the vertical passage at the rear of the block
between the oil-to-filter and oil-from-filter passages
(Fig. 17). Improper installation or missing plug could
cause erratic, low, or no oil pressure.
The oil plug must come out the bottom. Use flat
dowel, down the oil pressure sending unit hole from
the top, to remove oil plug.
(1) Remove oil pressure sending unit from back of
block.
(2) Insert a 3.175 mm (1/8 in.) finish wire, or
equivalent, into passage.
(3) Plug should be 190.0 to 195.2 mm (7-1/2 to
7-11/16 in.) from machined surface of block (Fig. 17).
If plug is too high, use a suitable flat dowel to posi-
tion properly.
(4)
If plug is too low, remove oil pan and No. 4 main
bearing cap. Use suitable flat dowel to position properly.
Coat outside diameter of plug with MopartStud and
Fig. 16 Measuring Valve Guide Wear
1 - VALVE
2 - SPECIAL TOOL C-3339
Fig. 17 Oil Line Plug
1 - RIGHT OIL GALLERY
2 - CYLINDER BLOCK
3 - OIL FROM FILTER TO SYSTEM
4 - OIL TO FILTER
5 - FROM OIL PUMP
6 - CRANKSHAFT
7 - PLUG
9 - 28 ENGINE 3.9LBR/BE
INTAKE/EXHAUST VALVES & SEATS (Continued)

Bearing Mount Adhesive. Plug should be 54.0 to 57.7
mm (2-1/8 to 2-5/16 in.) from bottom of the block.
CAMSHAFT & BEARINGS (IN
BLOCK)
REMOVALÐCAMSHAFT BEARINGS
(1) With engine completely disassembled, drive out
rear cam bearing core hole plug.
(2) Install proper size adapters and horseshoe
washers (part of Camshaft Bearing Remover/Installer
Tool C-3132-A) at back of each bearing shell. Drive
out bearing shells (Fig. 18).
REMOVALÐCAMSHAFT
(1) Disconnect battery negative cable.
(2) Remove radiator. (Refer to 7 - COOLING/EN-
GINE/RADIATOR - REMOVAL).
(3) Remove intake manifold. (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
REMOVAL).
(4) Remove distributor assembly. Refer to Ignition
Systems for the correct procedure.
(5) Remove cylinder head covers (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(6) Remove rocker arms.
(7) Remove push rods and tappets (Refer to 9 -
ENGINE/ENGINE BLOCK/HYDRAULIC LIFTERS
(CAM IN BLOCK) - REMOVAL). Identify each part
so it can be installed in the original locations.
(8) Remove timing chain cover. (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
(9) Align timing marks (Fig. 19) and remove tim-
ing chain and sprockets.
(10) Remove the three tensioner to block mounting
bolts and remove tensioner.(11) Install a long bolt into front of camshaft to aid
in removal of the camshaft. Remove camshaft, being
careful not to damage cam bearings with the cam
lobes.
INSTALLATIONÐCAMSHAFT BEARINGS
(1) Install new camshaft bearings with Camshaft
Bearing Remover/Installer Tool C-3132-A by sliding
the new camshaft bearing shell over proper adapter.
(2) Position rear bearing in the tool. Install horse-
shoe lock and, by reversing removal procedure, care-
fully drive bearing shell into place.
(3) Install remaining bearings in the same man-
ner. Bearings must be carefully aligned to bring oil
holes into full register with oil passages from the
main bearing. If the camshaft bearing shell oil holes
are not in exact alignment, remove and install them
correctly. Install a new core hole plug at the rear of
camshaft.Be sure this plug does not leak.
INSTALLATIONÐCAMSHAFT
(1) Lubricate camshaft lobes and camshaft bearing
journals and insert the camshaft to within 51 mm (2
inches) of its final position in cylinder block.
(2) Install Camshaft Holding Tool C-3509 with
tongue back of distributor drive gear (Fig. 20).
(3) Hold tool in position with a distributor lock-
plate bolt. This tool will restrict camshaft from being
pushed in too far and prevent knocking out the welch
plug in rear of cylinder block.Tool should remain
Fig. 18 Camshaft Bearings Removal and Installation
with Tool C-3132-A
1 - SPECIAL TOOL C-3132A
Fig. 19 Alignment of Timing Marks
1 - TIMING MARKS
BR/BEENGINE 3.9L 9 - 29
ENGINE BLOCK (Continued)

(8) Turn crankshaft and camshaft to line up with
keyway location in crankshaft sprocket and in cam-
shaft sprocket.
(9) Lift sprockets and chain (keep sprockets tight
against the chain in position as described).
(10) Slide both sprockets evenly over their respec-
tive shafts and use a straightedge to check alignment
of timing marks (Fig. 22).
(11) Install the camshaft bolt/cup washer. Tighten
bolt to 68 N´m (50 ft. lbs.) torque.
(12) Measure camshaft end play (Fig. 23). (Refer to
9 - ENGINE - SPECIFICATIONS) for proper clear-
ance. If not within limits, install a new timing chain
tensioner.
(13) Each tappet reused must be installed in the
same position at which it was removed.When cam-
shaft is replaced, all of the tappets must be
replaced.Install hydraulic tappets (Refer to 9 -
ENGINE/ENGINE BLOCK/HYDRAULIC LIFTERS
(CAM IN BLOCK) - INSTALLATION).
(14) Install timing chain cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION).
(15) Install intake manifold (Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD - INSTALLA-
TION).
(16) Install distributor.
(17) Install cylinder head covers (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
(18) Install radiator (Refer to 7 - COOLING/EN-
GINE/RADIATOR - INSTALLATION).
(19) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(20) Connect battery negative cable.
(21) Start engine and check for leaks.
CONNECTING ROD BEARINGS
STANDARD PROCEDURE-CONNECTING ROD
BEARING FITTING
Fit all rods on a bank until completed. DO NOT
alternate from one bank to another, because connect-
ing rods and pistons are not interchangeable from
one bank to another.
The bearing caps are not interchangeable and
should be marked at removal to ensure correct
assembly.
Each bearing cap has a small V-groove across the
parting face. When installing the lower bearing shell,
be certain that the V-groove in the shell is in line
with the V-groove in the cap. This provides lubrica-
tion of the cylinder wall in the opposite bank.The bearing shells must be installed so that the
tangs are in the machined grooves in the rods and
caps.
Limits of taper or out-of-round on any crankshaft
journals should be held to 0.025 mm (0.001 in.).
Bearings are available in 0.025 mm (0.001 in.), 0.051
mm (0.002 in.), 0.076 mm (0.003 in.), 0.254 mm
(0.010 in.) and 0.305 mm (0.012 in.) undersize.
Install the bearings in pairs. DO NOT use a new
bearing half with an old bearing half. DO NOT
file the rods or bearing caps.
CRANKSHAFT
DESCRIPTION
The crankshaft (Fig. 24) is of a forged steel splayed
type design, with four main bearing journals.The
crankshaft is located at the bottom of the engine
block and is held in place with four main bearing
caps.
OPERATION
The crankshaft transfers force generated by com-
bustion within the cylinder bores to the flywheel or
flexplate.
REMOVAL
(1) Remove the oil pan (Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - REMOVAL).
(2) Remove the oil pump (Refer to 9 - ENGINE/
LUBRICATION/OIL PUMP - REMOVAL).
(3) Identify bearing caps before removal. Remove
bearing caps and bearings one at a time.
(4) Lift the crankshaft out of the block.
Fig. 24 CrankshaftÐ3.9L Engine
BR/BEENGINE 3.9L 9 - 31
CAMSHAFT & BEARINGS (IN BLOCK) (Continued)