
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

(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)

PISTON & CONNECTING ROD
DESCRIPTION
The pistons are made of aluminum and have three
ring grooves, the top two grooves are for the compres-
sion rings and the bottom groove is for the oil control
ring. The connecting rods are forged steel and are
coined prior to heat treat. The piston pins are press
fit.
STANDARD PROCEDUREÐPISTON FITTING
Check the cylinder block bore for out-of-round,
taper, scoring, or scuffing.
Check the pistons for taper and elliptical shape
before they are fitted into the cylinder bore (Fig. 39).
Piston and cylinder wall must be clean and dry.
Specified clearance between the piston and the cylin-
der wall is 0.013-0.038 mm (0.0005-0.0015 in.) at
21ÉC (70ÉF).
Piston diameter should be measured at the top of
skirt, 90É to piston pin axis. Cylinder bores should be
measured halfway down the cylinder bore and trans-
verse to the engine crankshaft center line.
Pistons and cylinder bores should be measured at
normal room temperature, 21ÉC (70ÉF).
PISTON MEASUREMENTS CHART
PISTON A DIA = PISTON BORE
SIZE DIAMETER DIAMETER
MIN. MAX. MIN. MAX.
mm
(in.)mm
(in.)mm
(in.)mm (in.)
A99.280 99.294 99.308 99.320
(3.9087) (3.9092) (3.9098) (3.9103)
B99.294 99.306 99.320 99.333
(3.9092) (3.9097) (3.9103) (3.9108)
C99.306 99.319 99.333 99.345
(3.9097) (3.9102) (3.9108) (3.9113)
D99.319 99.332 99.346 99.358
(3.9102) (3.9107) (3.9113) (3.9118)
E99.332 99.344 99.358 99.371
(3.9107) (3.9112) (3.9118) (3.9123)
DESCRIPTION SPECIFICATION
PISTON PIN BORE 25.007 - 25.014 mm
(.9845 - .9848 in.)
RING GROOVE
HEIGHT4.0309 - 4.0538 mm
(OIL RAIL) (.1587 - .1596 in.)
RING GROOVE
HEIGHT2.0294 - 2.0548 mm
(COMPRESSION
RAIL)(.0799 - .0809 in.)
TOTAL FINISHED 594.6 2 grams
WEIGHT (20.974 .0706 ounces)
REMOVAL
(1) Remove the engine from the vehicle (Refer to 9
- ENGINE - REMOVAL).
(2) Remove the cylinder head (Refer to 9 -
ENGINE/CYLINDER HEAD - REMOVAL).
(3) Remove the oil pan (Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - REMOVAL).
(4) Remove top ridge of cylinder bores with a reli-
able ridge reamer before removing pistons from cyl-
inder block. Be sure to keep tops of pistons covered
during this operation.
(5) Be sure each connecting rod and connecting rod
cap is identified with the cylinder number. Remove
connecting rod cap. Install connecting rod bolt guide
set on connecting rod bolts.
(6) Pistons and connecting rods must be removed
from top of cylinder block. When removing the
assemblies from the engine, rotate crankshaft so that
Fig. 39 Piston Measurements
1 - 62.230 mm
(2.45 IN.)
9 - 40 ENGINE 3.9LBR/BE

DESCRIPTION SPECIFICATION
valve closed 378 N @ 41.66 mm
(85 lbs. @ 1.64 in.)
valve open 890 N @ 30.89 mm
(200 lbs. @ 1.212 in.)
Number of Coils 6.5
Installed Height 41.66 mm
(1.64 in.)
Wire Diameter 4.50 mm
(0.177 in.)
HYDRAULIC TAPPETS
Body Diameter 22.949 ± 22.962 mm
(0.9035 ± 0.9040 in.)
Clearance (to bore) 0.0279 ± 0.0610 mm
(0.0011 ± 0.0024 in.)
Dry Lash 1.524 ± 5.334 mm
(0.060 ± 0.210 in.)
Push Rod Length 175.64 ± 176.15 mm
(6.915 ± 6.935 in.)
OIL PRESSURE
Curb Idle (Min.*) 41.4 kPa (6 psi)
@ 3000 rpm 207 ± 552 kPa
(30 ± 80 psi)
Oil Pressure Bypass
Valve
Setting 62 ± 103 kPa
(9 ± 15 psi)
Switch Actuating
Pressure34.5 ± 48.3 kPa
(5 ± 7 psi)
* If oil pressure is zero at curb idle, DO NOT RUN
ENGINE.
OIL PUMP
Clearance over Rotors
(Max.)0.0381 mm
(0.0015 in.)DESCRIPTION SPECIFICATION
Inner Rotor Thickness
(Min.)20.955 mm
(0.825 in.)
Outer Rotor Clearance
(Max.)0.3556 mm
(0.014 in.)
Outer Rotor Diameter
(Min.)62.7126 mm
(2.469 in.)
Outer Rotor Thickness
(Min.)20.955 mm
(0.825 in.)
Tip Clearance between
Rotors
(Max.) 0.2032 mm
(0.008 in.)
PISTONS
Clearance at Top of Skirt 0.013 ± 0.038 mm
(0.0005 ± 0.0015 in.)
Land Clearance (Diam.) 0.635 ± 1.016 mm
(0.025 ± 0.040 in.)
Piston Length 86.360 mm (3.40 in.)
Piston Ring Groove
Depth
Groove #1&2 4.572 ± 4.826 mm
(0.180 ± 0.190 in.)
Groove #3 3.810 ± 4.064 mm
(0.150 ± 0.160 in.)
Weight 592.6 ± 596.6 grams
(20.90 ± 21.04 oz.)
PISTON PIN
Clearance in Piston 0.00635 ± 0.01905 mm
(0.00025 ± 0.00075 in.)
Diameter 24.996 ± 25.001 mm
(0.9841 ± 0.9843 in.)
End Play NONE
Length 75.946 ± 76.454 mm
(2.990 ± 3.010 in.)
9 - 74 ENGINE 5.2LBR/BE
ENGINE 5.2L (Continued)

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. 8). 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. 9).
(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. 8 Positioning Valve with Tool C-3973
1 - VALVE
2 - SPACER TOOL
Fig. 9 Measuring Valve Guide Wear
1 - VALVE
2 - SPECIAL TOOL C-3339
9 - 82 ENGINE 5.2LBR/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. 13). 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. 14). 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. 15).
(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. 13 Testing Valve Spring for Compressed
Length
1 - TORQUE WRENCH
2 - VALVE SPRING TESTER
Fig. 14 Positioning Valve with Tool C-3973
1 - VALVE
2 - SPACER TOOL
9 - 84 ENGINE 5.2LBR/BE
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).
ROCKER ARM / ADJUSTER
ASSEMBLY
REMOVAL
(1) Remove cylinder head cover and gasket (Refer
to 9 - ENGINE/CYLINDER HEAD/CYLINDER
HEAD COVER(S) - REMOVAL).
(2) Remove the rocker arm bolts and pivots (Fig.
16). Place them on a bench in the same order as
removed.
(3) Remove the push rods and place them on a
bench in the same order as removed.
INSTALLATION
(1) Rotate the crankshaft until the ªV8º mark lines
up with the TDC mark on the timing chain case
cover. This mark is located 147É ATDC from the No.1
firing position.
(2) Install the push rods in the same order as
removed.
(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.
CAUTION: DO NOT rotate or crank the engine dur-
ing or immediately after rocker arm installation.
Allow the hydraulic roller tappets adequate time to
bleed down (about 5 minutes).
(4) Install cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
Fig. 15 Measuring Valve Guide Wear
1 - VALVE
2 - SPECIAL TOOL C-3339
Fig. 16 Rocker Arms
1 - ROCKER ARMS
2 - CYLINDER HEAD
BR/BEENGINE 5.2L 9 - 85
INTAKE/EXHAUST VALVES & SEATS (Continued)