
DESCRIPTION SPECIFICATION
Weight 463 ± 473 grams (16.33
± 16.68 oz.)
Piston to Bore Clearance 0.013 ± 0.038 mm
(0.0005 ± 0.0015 in.)
Service Limit 0.0762 mm (0.003 in.)
PISTON PINS
Clearance in Piston 0.010 ± 0.020 mm
(0.0004 ± 0.0008 in.)
Diameter 24.996 ± 25.001 mm
(0.9841 ± 0.9843 in.)
End Play NONE
Length 67.8 ± 68.3 mm
(2.67 ± 2.69 in.)
PISTON RINGS
Ring Gap
Compression Rings 0.254 ± 0.508 mm
(0.010 ± 0.020 in.)
Oil Control (Steel Rails) 0.381 ± 1.397 mm
(0.015 ± 0.055 in.)
Ring Side Clearance
Compression Rings 0.074 ± 0.097 mm
(0.0029 ± 0.0038 in.)
Oil Ring (Steel Rails) 2.591 ± 2.743 mm
(0.102 ± 0.108 in.)
VALVE TIMING
Exhaust Valve
Closes (ATDC) 25É
Opens (BBDC) 60É
Duration 265É
Intake Valve
Closes (ATDC) 61É
Opens (BBDC) 6É
Duration 246É
Valve Overlap 31ÉCRANKSHAFT JOURNAL MARKING
LOCATION
MEASURE-
MENTITEM IDENTIFI-
CATIONLOCATION
OF
IDENTIFI-
CATION
0.0254 mm
(0.001 in.)
U/SCrankshaft
JournalsRorM
M-2-3 ect.
(indicating
No. 2 and
3 main
bearing
journal)
and/or
R-1-4 ect.
(indicating
No. 1 and
4
connecting
rod
journal)Milled flat
on No. 8
crankshaft
counter-
weight.
0.508 mm
(0.020 in.)
O/SCylinder
BoresA Following
engine
serial
number.
0.2032 mm
(0.008 in.)
O/SHydraulic
TappetsLDiamond-
shaped
stamp top
pad - front
of engine
and flat
ground on
outside
surface of
each O/S
tappet
bore.
0.127 mm
(0.005 in.)Valve
StemsX Milled pad
adjacent to
two tapped
holes 3/89
on each
end of
cylinder
head.
9 - 186 ENGINE 8.0LBR/BE
ENGINE 8.0L (Continued)

(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
valve seats should be 1.016-1.524 mm (0.040-0.060
inch).
VALVE SPRING INSPECTION
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 inch. Turn table of
Universal Valve Spring Tester Tool until surface is in
line with the 1-5/16 inch mark on the threaded stud.
Be sure the zero mark is to the front (Fig. 19). 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.
REMOVALÐVALVE STEM SEALS
NOTE: This procedure is done with the cylinder
head installed.
(1) Disconnect the negative cable from the battery.
(2) Set engine basic timing to Top Dead Center
(TDC) and remove air cleaner.
(3) Remove cylinder head covers (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL) and spark plugs (Refer to 8
- ELECTRICAL/IGNITION CONTROL/SPARK
PLUG - REMOVAL).
(4) Using suitable socket and flex handle at crank-
shaft retaining bolt, turn engine so that the piston of
the cylinder to be worked on, is at TDC on the com-
pression stroke.
(5) Remove rocker arms (Refer to 9 - ENGINE/
CYLINDER HEAD/ROCKER ARM / ADJUSTER
ASSY - REMOVAL).
(6) With air hose attached to an adapter installed
in the spark plug hole, apply 620-689 kPa (90-100
psi) air pressure.
(7) Using Valve Spring Compressor Tool
MD-998772A with adapter 6716A (Fig. 20), compress
valve spring and remove retainer valve locks and
valve spring.
(8) Remove the valve stem seal.
REMOVALÐVALVES AND VALVE SPRINGS
(1) Remove the cylinder head (Refer to 9 -
ENGINE/CYLINDER HEAD - REMOVAL).
(2) Special studs must be used to adapt the Valve
Spring Compressor Tool to the V-10 cylinder head
(Fig. 21). Install the metric end into the Special Tool
MD998772A and the 5/16 end into the cylinder head.
Fig. 18 Intake and Exhaust Valves
1 - MARGIN
2 - VALVE SPRING RETAINER LOCK GROOVE
3 - STEM
4-FACE
Fig. 19 Testing Valve Spring for Compressed
1 - TORQUE WRENCH
2 - VALVE SPRING TESTER
BR/BEENGINE 8.0L 9 - 197
INTAKE/EXHAUST VALVES & SEATS (Continued)

CRANKSHAFT OIL SEAL -
REAR
REMOVAL
NOTE: This procedure does not require the removal
of the seal retainer from the engine block.
(1) Remove the transmission.
(2) Carefully, remove the rear seal from the
retainer. Discard the oil seal.
INSTALLATION
(1) Wash all parts in a suitable solvent and inspect
carefully for damage or wear.
(2) Position Special Tool 6687 Seal Guide, onto the
crankshaft.
(3) Position the oil seal onto the Seal guide, then
using Special Tool 8359 Seal Installer and C±4171
Driver Handle, Install the oil seal.
(4) The seal face surface must be countersunk into
the retainer.762±1.27mm (0.030±0.050 in.).
(5) Install the transmission.
(6) Check and verify engine oil is at correct level.
(7) Start engine and check for leaks.
CRANKSHAFT REAR OIL SEAL
RETAINER
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove the transmission.
(3) Remove the drive plate / flywheel.
(4) Remove the oil pan (Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - REMOVAL).
(5) Remove the rear oil seal retainer mounting
bolts.
(6) Carefully remove the retainer from the engine
block.
INSTALLATION
(1) Throughly clean all gasket resdue from the
engine block.
(2) Use extream care and clean all gasket resdue
from the retainer.
(3) Apply a small amount of MopartSilicone Rub-
ber Adhesive Sealant to the retainer gasket. Position
the gasket onto the retainer.
(4) Position Special Tool 6687 Seal Guide onto the
crankshaft.
(5) Position the retainer and seal over the guide
and onto the engine block.
(6) Install the retainer mounting bolts. Tighten the
bolts to 22 N´m (16 ft. lbs.).(7) Install the oil pan (Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - INSTALLATION).
(8) Install the drive plate / flywheel.
(9) Install the transmission.
(10) Check and verify engine oil level.
(11) Start engine and check for leaks.
HYDRAULIC LIFTERS
DIAGNOSIS AND TESTINGÐHYDRAULIC
TAPPETS
Before disassembling any part of the engine to cor-
rect tappet noise, check the oil pressure. If vehicle
has no oil pressure gauge, install a reliable gauge at
the pressure sending-unit. The pressure should be
between 207-552 kPa (30-80 psi) at 3,000 RPM.
Check the oil level after the engine reaches normal
operating temperature. Allow 5 minutes to stabilize
oil level, check dipstick. The oil level in the pan
should never be above the FULL mark or below the
ADD OIL mark on dipstick. Either of these two con-
ditions could be responsible for noisy tappets.
OIL LEVEL
HIGH
If oil level is above the FULL mark, it is possible
for the connecting rods to dip into the oil. With the
engine running, this condition could create foam in
the oil pan. Foam in oil pan would be fed to the
hydraulic tappets by the oil pump causing them to
lose length and allow valves to seat noisily.
LOW
Low oil level may allow oil pump to take in air.
When air is fed to the tappets, they lose length,
which allows valves to seat noisily. Any leaks on
intake side of oil pump through which air can be
drawn will create the same tappet action. Check the
lubrication system from the intake strainer to the
pump cover, including the relief valve retainer cap.
When tappet noise is due to aeration, it may be
intermittent or constant, and usually more than one
tappet will be noisy. When oil level and leaks have
been corrected, operate the engine at fast idle. Run
engine for a sufficient time to allow all of the air
inside the tappets to be bled out.
TAPPET NOISE DIAGNOSIS
(1) To determine source of tappet noise, operate
engine at idle with cylinder head covers removed.
(2) Feel each valve spring or rocker arm to detect
noisy tappet. The noisy tappet will cause the affected
spring and/or rocker arm to vibrate or feel rough in
operation.
9 - 206 ENGINE 8.0LBR/BE

LUBRICATION
DESCRIPTION
A pressure feed type (gerotor) oil pump is located
in the engine front cover. The pump uses a pick-up
tube and screen assembly to gather engine oil from
the oil pan (Fig. 51).
OPERATION
The pump draws oil through the screen and inlet
tube from the sump at the rear of the oil pan. The oil
is driven between the inner and outer gears of the oil
pump, then forced through the outlet in the engine
front cover. An oil gallery in the front cover channels
the oil to the inlet side of the full flow oil filter. After
passing through the filter element, the oil passes
from the center outlet of the filter through an oil gal-
lery that channels the oil up to the tappet galleries,
which extends the entire length of block.
Galleries extend downward from the main oil gal-
lery to the upper shell of each main bearing. The
crankshaft is drilled internally to pass oil from the
main bearing journals to the connecting rod journals.
Each connecting rod bearing has half a hole in it, oil
passes through the hole when the rods rotate and the
hole lines up, oil is then thrown off as the rod
Fig. 50 Engine Rear Support Cushion Assembly
Fig. 51 Pressure Feed Type (Gerotor) Oil PumpÐ
Typical
1 - OUTER ROTOR
2 - INNER ROTOR
3 - OIL PUMP COVER
4 - TIMING CHAIN COVER
9 - 214 ENGINE 8.0LBR/BE
REAR MOUNT (Continued)

clearance between inner and outer rotors is 0.150
mm (0.006 inch) or more, replace both rotors.
Place a straightedge across the face of the timing
chain cover pump body, between bolt holes (Fig. 66).
If a feeler gauge of 0.077 mm (0.003 inch) or more
can be inserted between rotors and the straightedge,
and the rotors are within specifications, replace tim-
ing chain cover.
Inspect oil pressure relief valve plunger for scoring
and free operation in its bore. Small marks may be
removed with 400-grit wet or dry sandpaper.
The relief valve spring has a free length of approx-
imately 49.5 mm (1.95 inches). The spring should
test between 100 and 109 N (22.5 and 24.5 pounds)when compressed to 34 mm (1-11/32 inches). Replace
spring that fails to meet these specifications.
If oil pressure was low and pump is within specifi-
cations, inspect for worn engine bearings or other
reasons for oil pressure loss.
INSTALLATION
(1) Lubricate both oil pump rotors using petroleum
jelly or lubriplate and install in the timing chain
cover. Use new parts as required (Fig. 67).
Fig. 64 Measuring Outer Rotor Clearance in Cover
1 - FEELER GAUGE
2 - OUTER ROTOR
Fig. 65 Measuring Inner Rotor Clearance in Cover
1 - FEELER GAUGE
2 - OUTER ROTOR
3 - INNER ROTOR
Fig. 66 Measuring Clearance Over Rotors
1 - FEELER GAUGE
2 - STRAIGHT EDGE
Fig. 67 Priming Oil Pump.
1 - FILL WITH PETROLEUM JELLY OR LUBER PLATE
BR/BEENGINE 8.0L 9 - 221
OIL PUMP (Continued)

INSPECTIONÐCYLINDER HEAD
Inspect the cylinder head for cracks in the combus-
tion surface. Pressure test any cylinder head that is
visibly cracked. A cylinder head that is cracked
between the injector bore and valve seat can be pres-
sure tested and reused if OK; however, if the crack
extendsintothe valve seat, the valve seatmustbe
replaced.
Visually inspect the cylinder block and head com-
bustion surfaces for localized dips or imperfections.
Check the cylinder head and block combustion sur-
faces for overall out-of-flatness. If either the visual or
manual inspection exceeds the limits, then the head
or block must be surfaced.
Check the top surface for damage caused by the
cylinder head gasket leaking between cylinders.
Inspect the block and head surface for nicks, ero-
sion, etc.
Check the head distortion (Fig. 25). The distortion
of the combustion deck face is not to exceed 0.010
mm (0.0004 inch) in any 50.8 mm (2.00 inch) diame-
ter. Overall variation end to end or side to side 0.30
mm (0.012 inch).
DO NOT proceed with the in-chassis overhaul if
the cylinder head or block surface is damaged or not
flat (within specifications).
Visually inspect the cylinder head bolts for dam-
aged threads, corroded/pitted surfaces, or a reduced
diameter due to bolt stretching.
If the bolts are not damaged, their ªfree lengthº
should be measured using the cap screw stretch
gauge provided with the replacement head gasket.
Place the head of the bolt against the base of the slot
and align the bolt with the straight edge of gauge
(Fig. 26). If the end of the bolt touches the foot of the
gauge, the boltmustbe discarded.The maximum
bolt free length is 132.1 mm (5.200 in.).
INSPECTIONÐCROSSHEADS
Inspect the crossheads for cracks and/or excessive
wear on rocker lever and valve tip mating surfaces
(Fig. 27). Replace any crossheads that exhibit abnor-
mal wear or cracks.
INSPECTIONÐPUSHRODS
Inspect the push rod ball and socket for signs of
scoring. Check for cracks where the ball and the
socket are pressed into the tube (Fig. 28).
Roll the push rod on a flat work surface with the
socket end hanging off the edge (Fig. 29). Replace
any push rod that appears to be bent.
INSTALLATION
WARNING: THE OUTSIDE EDGE OF THE HEAD
GASKET IS VERY SHARP. WHEN HANDLING THE
NEW HEAD GASKET, USE CARE NOT TO INJURE
YOURSELF.
(1) Install a new gasket with the part number side
up, and locate the gasket over the dowel sleeves.
(2) Using an engine lifting crane, lower the cylin-
der head onto the engine.
Fig. 25 Cylinder Head Combustion Deck Face
1 - STRAIGHT EDGE
2 - FEELER GAUGE
Fig. 26 Head Bolt Stretch Gauge
Fig. 27 Inspecting Crosshead for Cracks
9 - 250 ENGINE 5.9L DIESELBR/BE
CYLINDER HEAD (Continued)

CYLINDER HEAD COVER(S)
REMOVAL
(1) Disconnect both battery negative cables.
(2) Loosen the five (5) cylinder head cover bolts
(Fig. 34). Remove the front three bolts and leave the
rear two bolts in the cover.
(3) Lift cover off of cylinder head.
CLEANING
Using a suitable solvent, Clean and dry gasket
mating surfaces on cylinder head and cover. Wipe
gasket dry and inspect for re-use.
INSPECTION
The cylinder head cover gasket and isolators
are reusable.However, should cracks be present in
the rubber/silicone construction, the defective compo-
nents should be replaced.
INSTALLATION
(1) Install the gasket as shown in (Fig. 34). Make
sure the gasket is properly located around the cylin-
der head bolts, with the words ªtop frontº facing up
and towards front of engine.(2) Place two bolts and isolators into the rear two
mounting holes and install the cover.
(3) Install the remaining bolts and isolators. Start-
ing with the center bolt, torque in a circular pattern
to 24 N´m (18 ft. lbs.).
(4) Connect both battery negative cables.
INTAKE/EXHAUST VALVES &
SEATS
DESCRIPTION
The valves are made of heat resistant steel, and
have chrome plated stems to prevent scuffing. The
intake and exhaust valves are both similar in head
diameter and overall length, but they have unique
face angles which makes them non-interchangeable.
The valves are distinguished by unique dimples on
the exhaust valve head (Fig. 35).
The exhaust valve springs are made from high
strength, chrome silicon steel. The exhaust valve
springs are also exhaust brake compatible.
STANDARD PROCEDURE-VALVES,GUIDES AND
SPRINGS
REMOVAL
(1) Remove cylinder head (Refer to 9 - ENGINE/
CYLINDER HEAD - REMOVAL).
(2) Support cylinder head on stands, or install
head bolts upside down (through combustion surface
side) to protect injector tips from damage from work
bench.
(3) Remove the injector clamp (Fig. 36) from the
cylinder(s) to be serviced.Do not remove the bolt
shown in (Fig. 36).
Fig. 34 Cylinder Head Cover and Gasket
1 - BOLT (5)
2 - GASKET
3 - ªTOP FRONTº
4 - ISOLATOR (5)
Fig. 35 Valve Identification
1 - INTAKE VALVES
2 - EXHAUST VALVES
BR/BEENGINE 5.9L DIESEL 9 - 253

Measure the valve spring free length and maxi-
mum inclination (Fig. 44).
Test valve spring force with tool C-647 (Fig. 45).
INSTALLATION
(1) Install new valve seals. The yellow springs are
for the intake valves and the green seals are for the
exhaust valves.(2) Install the valves in their original postion. The
exhaust valves are identified by a dimple on the
valve head (Fig. 46).
(3) Install the valve springs and retainer.
(4) Install the valve spring compressor tool 8319±A
as shown in (Fig. 37) and (Fig. 38).
(5) Compress the valve springs and install the
valve retaining locks (Fig. 39).
(6) Remove the compressor and repeat the proce-
dure on the remaining cylinders.
(7) Install the injector clamp and hold down bolts
and tighten to 10 N´m (89 in. lbs.) torque.
(8) Install the cylinder head (Refer to 9 - ENGINE/
CYLINDER HEAD - INSTALLATION).
STANDARD PROCEDUREÐVALVE LASH
ADJUSTMENT AND VERIFICATION
NOTE: To obtain accurate readings, valve lash mea-
surements AND adjustments should only be per-
formed when the engine coolant temperature is less
than 60É C (140É F).
The 24±valve overhead system is a ªlow-mainte-
nanceº design. Routine adjustments are no longer
necessary, however, measurement should still take
place when trouble-shooting performance problems,
or upon completion of a repair that includes removal
and installation of the valve train components.
(1) Disconnect battery negative cables.
Fig. 44 Measure Valve Spring Free Length and Max.
Inclination
VALVE SPRING FREE LENGTH
47.75 mm (1.88 in.)
MAX INCLINATION
1.5 mm (.059 in.)
Fig. 45 Testing Valve Spring with Tool C-647
1 - SPECIAL TOOL C-647
VALVE SPRING FORCE 35.33 mm @ 339.8 N (1.39 IN. @76.4
lbs.)
Fig. 46 Valve Identification
1 - INTAKE VALVES
2 - EXHAUST VALVES
9 - 256 ENGINE 5.9L DIESELBR/BE
INTAKE/EXHAUST VALVES & SEATS (Continued)