Dodge Dakota (R1). Manual - part 530

VALVE STAND DOWN

Valve stand down is to maintain the adequate com-

pression ratio.

(1) Invert cylinder head.
(2) Fit each valve to its respective valve guide.
(3) Using a straight edge and feeler gauge (Fig.

38), check valve head stand down: Inlet valve head
stand down 1.08 to 1.34 mm (.042 to .052 ins.) and
exhaust valve stand down .99 to 1.25 mm (.035 to
.049 ins.).

(4) If valve head stand down is not in accordance

with above, discard original valves, check stand down
with new valves and recut valve seat inserts to
obtain correct stand down.

VALVE GUIDES

(1) Valve Guides height requirement.
(2) Measurement A (Fig. 39): 13.50 - 14.00 mm.

VALVE STEM-TO-GUIDE CLEARANCE
MEASUREMENT

(1) Measure and record internal diameter to valve

guides. Valve guide internal diameter is 8.0 to 8.015
mm (.3149 to .3155 ins.).

(2) Measure valve stems and record diameters.

Intake valve stem diameter 7.94 to 7.96 mm (.3125 to
.3133 in.). Exhaust valve stem diameter 7.92 to 7.94
mm (.3118 to .31215 in.).

(3) Subtract diameter of valve stem from internal

diameter of its respective valve guide to obtain valve
stem clearance in valve guide. Clearance of inlet
valve stem in valve guide is .040 to .075 mm (.0015
to .0029 in.). Clearance of exhaust valve stem in
valve guide is .060 to .093 mm (.0023 to .0036 in.).

(4) If valve stem clearance in valve guide exceeds

tolerances, new valve guides must be installed.

ROCKER ARMS AND
PUSHRODS

REMOVAL

(1) Disconnect the negative battery cable.
(2) Discharge

the

air

conditioning

system,

equipped. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING/REFRIGERANT

STAN-

DARD PROCEDURE).

(3) If equipped with air conditioning, remove the

service valves and cap the compressor ports. Refer to
Group 24, Heating and Air Conditioning.

(4) Remove the generator bracket.
(5) Remove the cylinder head cover (Refer to 9 -

ENGINE/CYLINDER

HEAD/CYLINDER

HEAD

COVER(S) - REMOVAL).

(6) Remove the rocker arm retaining nut (Fig. 40).
(7) Remove the rocker assembly. Place them on a

bench in the same order as removed.

(8) Remove the push rods and place them on a

bench in the same order as removed.

CLEANING

Clean all the components (Fig. 41) with cleaning

solvent.

Use compressed air to blow out the oil passages in

the rocker arms and push rods.

MEASUREMENT

INTAKE

EXHAUST

7.940-7.960

7.922-7.940

8.00-8.015

8.000-8.015

1.08-1.34

0.990-1.250

+0.07

2.2 ± 0.08

2.09

0.09

1.80-2.20

1.65-2.05

2.73-3.44

2.45-3.02

41.962-41.985

35.964-35.987

42.070-42.086

36.050-36.066

7.14-7.19

7.00-7.05

3.11-3.26

3.10-3.25

Fig. 38 Checking Valve Stand Down

Fig. 39 Valve Guide Height

9a - 38

ENGINE 2.5L VM DIESEL INTERNATIONAL

INTAKE/EXHAUST VALVES AND SEATS (Continued)

INSPECTION

Inspect the pivot surface area of each rocker arm.

Replace any that are scuffed, pitted, cracked or
excessively worn.

Inspect the valve stem tip contact surface of each

rocker arm and replace any rocker arm that is deeply
pitted.

Inspect each push rod end for excessive wear and

replace as required. If any push rod is excessively
worn because of lack of oil, replace it and inspect the
corresponding hydraulic tappet for excessive wear.

Inspect the push rods for straightness by rolling

them on a flat surface or by shining a light between
the push rod and the flat surface.

A wear pattern along the length of the push rod is

not normal. Inspect the engine cylinder head for
obstruction if this condition exists.

INSTALLATION

WARNING: During the installation of the rocker arm
assemblies it is possible to cause valve interfer-
ence between the piston and valve if the piston is
near Top Dead Center (TDC). This is due to the slow
bleed down rate of the tappets when adjusting the
rocker arm assemblies. Follow the procedure below
to ensure that engine damage does not occur.

(1) Install the rocker arm assemblies in the same

order as removed.

• Bring piston # 1 to Top Dead Center.

• Rotate the engine 40° counter clockwise and

stop.

• At this point tighten all of the rocker arm nuts.

Torque nuts to 27 N·m (20 ft. lbs.).

NOTE: You must allow 30 minutes before starting
the engine once the rocker arms are torqued. This
will allow the hydraulic tappets to stabilize and pre-
vent the possibility of piston to valve contact.

(2) Install the cylinder head cover. (Refer to 9 -

ENGINE/CYLINDER

HEAD/CYLINDER

HEAD

COVER(S) - REMOVAL).

(3) Evacuate and charge the air conditioning sys-

tem. (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING/REFRIGERANT

STANDARD

PROCEDURE).

(4) Connect the negative battery cable.

Fig. 40 Rocker Arm Retaining Nut

1 - ROCKER ARM ASSEMBLY
2 - ROCKER ARM RETAINING NUTS
3 - ROCKER ARM SPRING PLATE

Fig. 41 Rocker Arm Components

1 - ROCKER ARM
2 - SPRING PLATE
3 - ROCKER SUPPORT
4 - PUSH ROD
5 - HYDRAULIC TAPPET
6 - CAMSHAFT
7 - ANTIROTATION BRACKET

ENGINE 2.5L VM DIESEL INTERNATIONAL

9a - 39

ROCKER ARMS AND PUSHRODS (Continued)

VALVE SPRINGS

REMOVAL

This procedure can be done with the engine cylin-

der head installed on the block.

(1) Disconnect the negative battery cable.
Each valve spring is held in place by a retainer

and a set of conical valve locks. The locks can be
removed only by compressing the valve spring.

(2) Remove the cylinder head cover. (Refer to 9 -

ENGINE/CYLINDER

HEAD/CYLINDER

HEAD

COVER(S) - REMOVAL).

(3) Remove the rocker arms assemblies and push

rods. (Refer to 9 - ENGINE/CYLINDER HEAD/
ROCKER ARMS - REMOVAL). Retain the push rods,
and rocker arms assemblies in the same order and
position as removed.

(4) Inspect the springs and retainer for cracks and

possible signs of weakening.

(5) Install an air hose adaptor in the fuel injector

hole.

(6) Connect an air hose to the adapter and apply

air pressure slowly. Maintain at least 621 kPa (90
psi) of air pressure in the cylinder to hold the valves
against their seats.

(7) Tap the retainer or tip with a rawhide hammer

to loosen the lock from the retainer. Use Valve Spring
Compressor Tool to compress the spring and remove
the locks.

(8) Remove the valve spring and retainer.
(9) Inspect the valve stems, especially the grooves.

An Arkansas smooth stone should be used to remove
nicks and high spots.

INSTALLATION

(1) Install the valve spring and retainer.
(2) Compress the valve spring with Valve Spring

Compressor Tool and insert the valve locks. Release
the spring tension and remove the tool. Tap the
spring from side-to-side to ensure that the spring is
seated properly on the engine cylinder head.

(3) Disconnect the air hose. Remove the adaptor

from the fuel injector hole and install the fuel injec-
tor.

(4) Repeat the procedures for each remaining valve

spring to be removed.

(5) Install the push rods. Ensure the bottom end of

each rod is centered in the plunger cap seat of the
hydraulic valve tappet.

(6) Install the rocker arm assemblies, in their orig-

inal locations. Torque nuts to 29.4 N·m (264 in. lbs.).

(7) Install the cylinder head cover. (Refer to 9 -

ENGINE/CYLINDER

HEAD/CYLINDER

HEAD

COVER(S) - REMOVAL).

(8) Connect the negative battery cable.

CAMSHAFT

REMOVAL

(1) Disconnect the negative battery cable.
(2) Remove the cylinder head cover (Refer to 9 -

ENGINE/CYLINDER

HEAD/CYLINDER

HEAD

COVER(S) - REMOVAL).

(3) Remove the cylinder heads (Refer to 9 -

ENGINE/CYLINDER HEAD - REMOVAL).

(4) Remove the rocker arm assemblies, push rods,

and hydraulic tappets. (Refer to 9 - ENGINE/CYLIN-
DER HEAD/ROCKER ARMS - REMOVAL) and
(Refer to 9 - ENGINE/CYLINDER HEAD/HYDRAU-
LIC LIFTERS - REMOVAL).

(5) Remove the fan and set fan inside fan shroud

then remove fan shroud and fan as an assembly.

(6) Remove the accessary drive belt (Refer to 7 -

COOLING/ACCESSORY

DRIVE/DRIVE

BELTS

REMOVAL).

(7) Remove the radiator (Refer to 7 - COOLING/

ENGINE/RADIATOR - REMOVAL).

(8) Remove the A/C condenser (Refer to 24 - HEAT-

ING & AIR CONDITIONING/PLUMBING/A/C CON-
DENSER - REMOVAL).

(9) Remove the vibration damper (Refer to 9 -

ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
REMOVAL).

(10) Remove the power steering pump pulley.
(11) Remove timing gear cover (Refer to 9 -

ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).

(12) Rotate the engine to align the timing marks

as shown (Fig. 42).

(13) Unscrew the flange bolts and remove cam-

shaft (Fig. 43).

THRUST PLATE INSPECTION

Check the thickness (Fig. 44) of the plate at points

a-b-c-d. If the measurement is not between 3.950 -
4.050 it must be changed.

INSTALLATION

(1) Coat the camshaft journals with clean engine

oil and carefully install the camshaft complete with
thrust plate and gear. Tighten retaining bolts to 27.5
N·m (20 ft. lbs.) torque. Be sure to align the timing
marks as shown (Fig. 45).

(2) Install the hydraulic tappets and retainers

(Refer to 9 - ENGINE/CYLINDER HEAD/HYDRAU-
LIC LIFTERS - INSTALLATION).

(3) Install

the

cylinder

heads

(Refer

ENGINE/CYLINDER HEAD - INSTALLATION).

(4) Install the push rods and rocker arm assem-

blies (Refer to 9 - ENGINE/CYLINDER HEAD/
ROCKER ARMS - INSTALLATION).

9a - 40

ENGINE 2.5L VM DIESEL INTERNATIONAL

(5) Install the cylinder head cover (Refer to 9 -

ENGINE/CYLINDER

HEAD/CYLINDER

HEAD

COVER(S) - INSTALLATION).

(6) Install the timing gear cover (Refer to 9 -

ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION).

(7) Install the vibration damper (Refer to 9 -

ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
INSTALLATION).

(8) Install the A/C condenser (Refer to 24 - HEAT-

ING & AIR CONDITIONING/PLUMBING/A/C CON-
DENSER - INSTALLATION).

(9) Install the radiator (Refer to 7 - COOLING/EN-

GINE/RADIATOR - INSTALLATION).

Fig. 42 Timing Marks

1 - VACUUM PUMP
2 - CAMSHAFT
3 - INJECTION PUMP
4 - TIMING MARKS
5 - OIL PUMP
6 - CRANKSHAFT

Fig. 43 Camshaft Removal

Fig. 44 Camshaft Thrust Plate

Fig. 45 Timing Marks

1 - CAMSHAFT GEAR
2 - CRANKSHAFT GEAR
3 - OIL PUMP
4 - VACUUM PUMP

ENGINE 2.5L VM DIESEL INTERNATIONAL

9a - 41

CAMSHAFT (Continued)

Content .. 528 529 530 531 ..