Dodge RAM TRUCK 1500 1995 Service Manual page 869

e n
3.9L ENGINE 9 - 25
(8) Using Valve Spring Compressor Tool
MD-998772A, compress valve spring and remove re­
tainer valve locks and valve spring.
(9) Install seals on the exhaust valve stem and po­
sition down against valve guides.
(10) The intake valve stem seals should be pushed
firmly and squarely over the valve guide using the
valve stem as a guide. DO NOT force seal against top
of guide. When installing the valve retainer locks,
compress the spring only enough to install the locks.
(11) Follow the same procedure on the remaining 5
cylinders using the firing sequence 1-6-5-4-3-2. Make
sure piston in cylinder is at TDC on the valve spring
that is being removed.
(12) Remove adapter from the No.l spark plug
hole.
(13) Install rocker arms.
(14) Install covers and coil wire to distributor.
(15) Install air cleaner.
(16) Road test vehicle.
CYLINDER
H E 1 D S
The alloy cast iron cylinder heads (Fig. 3) are held
in place by 8 bolts. The spark plugs are located in
the peak of the wedge between the valves.
SPARK SPARK INTAKE
PLUGS PLUG VALVE
EXHAUST INTAKE EXHAUST
VALVE VALVES VALVES J9309-35
Fig. 3 Cylinder Head Assembly
REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Drain cooling system (refer to Group 7, Cooling
System for the proper procedures).
(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.
(7) Perform fuel system pressure release procedure
(before attempting any repairs Refer to Group 14,
Fuel Systems).
(8) Disconnect the fuel lines.
(9) Disconnect accelerator linkage and if so
equipped, the speed control and transmission kick-
down cables.
(10) Remove the return spring.
(11) Remove distributor cap and wires.
(12) Disconnect the coil wires.
(13) Disconnect heat indicator sending unit wire.
(14) Disconnect heater hoses and bypass hose.
(15) Remove cylinder head covers and gaskets.
(16) Remove intake manifold and throttle body as
an assembly. Discard the flange side gaskets and the
front and rear cross-over gaskets.
(17) Remove exhaust manifolds.
(18) Remove rocker arm assemblies and push rods.
Identify to ensure installation in original locations.
(19) Remove the head bolts from each cylinder
head and remove cylinder heads. Discard the cylin­
der head gasket.
(20) 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 ex­
ceeds 0.00075 mm/mm (0.00075 inch/inch) times the
span length 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).
Inspect push rods. Replace worn or bent rods.
INSTALLATION
(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.
4). 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,
make sure the piston in that cylinder is NOT at
TDC. Contact between the valves and piston could
occur.