Dodge Durango (DN). Manual — part 448

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. 77).

VALVES

Inspect the remaining margin after the valves are

refaced (Fig. 78). 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. 79).

(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.

Fig. 77 Valve Face and Seat Angles

1 – CONTACT POINT

ITEM

DESCRIPTION

SPECIFICATION

A

SEAT WIDTH -

1.016 - 1.524

mm

INTAKE

(0.040 - 0.060

in.)

EXHAUST

1.524 - 2.032

mm

(0.060 - 0.080

in.)

B

FACE ANGLE

(INT. AND

EXT.)

43

1

⁄

4

° - 43

3

⁄

4

°

C

SEAT ANGLE

(INT. AND

EXT.)

44

1

⁄

4

° - 44

3

⁄

4

°

D

CONTACT

SURFACE

—

Fig. 78 Intake and Exhaust Valves

1 – MARGIN
2 – VALVE SPRING RETAINER LOCK GROOVE
3 – STEM
4 – FACE

Fig. 79 Refacing Valve Seats

1 – STONE
2 – PILOT
3 – VALVE SEAT
4 – SHROUD

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DISASSEMBLY AND ASSEMBLY (Continued)

(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.

(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
inch). The width of the exhaust seats should be
1.524-2.032 mm (0.060-0.080 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
Universals 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. 80).
Place spring over stud on the table and lift compress-
ing 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 mea-
surements are indicated on the table for finer adjust-
ments. Refer to specifications to obtain specified
height and allowable tensions. Discard the springs
that do not meet specifications.

OIL PUMP

DISASSEMBLE

(1) Remove the relief valve as follows:

(a) Remove cotter pin. Drill a 3.175 mm (1/8

inch) hole into the relief valve retainer cap and
insert a self-threading sheet metal screw.

(b) Clamp screw into a vise and while support-

ing oil pump, remove cap by tapping pump body
using a soft hammer. Discard retainer cap and
remove spring and relief valve (Fig. 81).

(2) Remove oil pump cover (Fig. 82).
(3) Remove pump outer rotor and inner rotor with

shaft (Fig. 82).

(4) Wash all parts in a suitable solvent and inspect

carefully for damage or wear.

ASSEMBLE

(1) Install pump rotors and shaft, using new parts

as required.

(2) Position the oil pump cover onto the pump

body. Tighten cover bolts to 11 N·m (95 in. lbs.)
torque.

(3) Install the relief valve and spring. Insert the

cotter pin.

(4) Tap on a new retainer cap.
(5) Prime oil pump before installation by filling

rotor cavity with engine oil.

Fig. 80 Testing Valve Spring for Compressed

Length

1 – TORQUE WRENCH
2 – VALVE SPRING TESTER

Fig. 81 Oil Pressure Relief Valve

1 – OIL PUMP ASSEMBLY
2 – COTTER PIN
3 – RELIEF VALVE
4 – RETAINER CAP
5 – SPRING

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5.2L ENGINE

9 - 123

DISASSEMBLY AND ASSEMBLY (Continued)

CYLINDER BLOCK

DISASSEMBLE

With Engine removed from vehicle:
(1) Remove the cylinder heads. refer to Cylinder

Head in this section for correct procedure.

(2) Remove

the

exhaust

manifolds.

Refer

to

Exhaust Manifolds in this section.

(3) Remove the oil pan. Refer to Oil Pan in this

section.

(4) Remove the piston and connecting rod assem-

blies. Refer to Piston and Connecting Rod in this sec-
tion.

(5) Remove the crankshaft. Refer to Crankshaft in

this section.

(6) Remove the core plugs.

ASSEMBLE

(1) Install the core plugs.
(2) Install the crankshaft.
(3) Install the piston and connecting rods.
(4) Install the oil pan.
(5) Install the cylinder heads.
(6) Install the exhaust manifolds.
(7) Install the intake manifold.
(8) Install the engine into the vehicle.

CLEANING AND INSPECTION

CYLINDER HEAD COVER

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.

CYLINDER HEAD ASSEMBLY

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 0.00075 mm/mm (0.00075 inch/inch) times
the span length in inches 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).

PISTON AND CONNECTING ROD ASSEMBLY

INSPECTION

Check the crankshaft connecting rod journal for

excessive wear, taper and scoring.

Check the cylinder block bore for out-of-round,

taper, scoring and scuffing.

Check the pistons for taper and elliptical shape

before they are fitted into the cylinder bore (Fig. 83).

OIL PAN

CLEANING

Clean the block and pan gasket surfaces.
Trim or remove excess sealant film in the rear

main cap oil pan gasket groove. DO NOT remove
the sealant inside the rear main cap slots.

If present, trim excess sealant from inside the

engine.

Fig. 82 Oil Pump

1 – INNER ROTOR AND SHAFT
2 – BODY
3 – DISTRIBUTOR DRIVESHAFT (REFERENCE)
4 – COTTER PIN
5 – RETAINER CAP
6 – SPRING
7 – RELIEF VALVE
8 – LARGE CHAMFERED EDGE
9 – BOLT
10 – COVER
11 – OUTER ROTOR

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DISASSEMBLY AND ASSEMBLY (Continued)

Clean oil pan in solvent and wipe dry with a clean

cloth.

Clean oil screen and pipe thoroughly in clean sol-

vent. Inspect condition of screen.

INSPECTION

Inspect oil drain plug and plug hole for stripped or

damaged threads. Repair as necessary.

Inspect oil pan mounting flange for bends or distor-

tion. Straighten flange, if necessary.

OIL PUMP

INSPECTION

Mating surface of the oil pump cover should be

smooth. Replace pump assembly if cover is scratched
or grooved.

Lay a straightedge across the pump cover surface

(Fig. 84). If a 0.038 mm (0.0015 inch) feeler gauge
can be inserted between cover and straightedge,
pump assembly should be replaced.

Measure thickness and diameter of OUTER rotor.

If outer rotor thickness measures 20.9 mm (0.825
inch) or less or if the diameter is 62.7 mm (2.469
inches) or less, replace outer rotor (Fig. 85).

If inner rotor measures 20.9 mm (0.825 inch) or

less, replace inner rotor and shaft assembly (Fig. 86).

Slide outer rotor into pump body. Press rotor to the

side

with

your

fingers

and

measure

clearance

between rotor and pump body (Fig. 87). If clearance
is 0.356 mm (0.014 inch) or more, replace oil pump
assembly.

Install inner rotor and shaft into pump body. If

clearance between inner and outer rotors is 0.203
mm (0.008 inch) or more, replace shaft and both
rotors (Fig. 88).

Fig. 83 Piston Measurements

1 – 49.53 mm

(1.95 IN.)

PISTON MEASUREMENT CHART

PISTON

A DIA = PISTON

BORE

SIZE

DIAMETER

DIAMETER

MIN.

MAX.

MIN.

MAX.

mm

(in.)

mm

(in.)

mm

(in.)

mm (in.)

A

—

—

—

—

B

101.580

101.592

101.605

101.618

(3.9992)

(3.9997)

(4.0002)

(4.0007)

C

101.592

101.605

101.618

101.630

(3.9997)

(4.0002)

(4.0007)

(4.0012)

D

101.605

101.618

101.630

101.643

(4.0002)

(4.0007)

(4.0012)

(4.0017)

E

—

—

—

—

DESCRIPTION

SPECIFICATION

PISTON PIN

25.007 - 25.015 mm

BORE

(.9845 -.9848 in.)

RING GROOVE

HEIGHT

OIL RAIL

4.033 - 4.058 mm

(.1588 -.1598 in.)

COMPRESSION

RAIL

1.529 - 1.554 mm

(.0602 -.0612 in.)

TOTAL FINISHED

470.8

6

2 grams

WEIGHT

(16.607

6

.0706 ounces)

Fig. 84 Checking Oil Pump Cover Flatness

1 – COVER
2 – STRAIGHT EDGE
3 – FEELER GAUGE

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5.2L ENGINE

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CLEANING AND INSPECTION (Continued)