the old insert and machining an oversize insert bore. Replacement
oversize insert is usually chilled and the cylinder head is sometimes
warmed. Valve seat is pressed into the head. This operation requires
specialized machine shop equipment.
Valve Seat Concentricity
Using dial gauge, install gauge pilot in valve guide.
Position gauge arm on the valve seat. Adjust dial indicator to zero.
Rotate arm 360 degrees and note reading. Runout should not exceed
specification.
To check valve-to-valve seat concentricity, coat valve face
lightly with Prussian Blue dye. Install valve and rotate it on valve
seat. If pattern is even and entire seat is coated at valve contact
point, valve is concentric with the seat.
REASSEMBLY
Valve Stem Installed Height
Valve stem installed height must be checked when new valves
are installed or when valves or valve seats have been ground. Install
valve in valve guide. Measure distance from tip of valve stem to
spring seat. See Fig. 11. Distance must be within specifications.
Fig. 11: Measuring Valve Stem Installed Height - Typical
This Graphic For General Information Only
Remove valve and grind valve stem tip if height exceeds
specification. Valve tips are surface hardened. DO NOT remove more
than .010" (.25 mm) from tip. Chamfer sharp edge of reground valve
tip. Recheck valve stem installed height.
VALVE STEM OIL SEALS
Valve stem oil seals must be installed on valve stem. See
Fig. 2 . Seals are needed due to pressure differential at the ends of
valve guides. Atmospheric pressure above intake guide, combined with
manifold vacuum below guide, causes oil to be drawn into the cylinder.
Exhaust guides also have pressure differential created by
exhaust gas flowing past the guide, creating a low pressure area. This
low pressure area draws oil into the exhaust system.
Replacement (On Vehicle)
Mark rocker arm or overhead cam components for location.
Remove rocker arm components or overhead cam components. Components
must be installed in original location. Remove spark plugs. Valve stem
oil seals may be replaced by holding valves against seats using air
pressure.
Air pressure must be installed in cylinder using an adapter
for spark plug hole. An adapter can be constructed by welding air hose
connection to spark plug body with porcelain removed.
Install adapter in spark plug hole. Apply a minimum of 140
psi (9.8 kg/cm
) to adapter. Air pressure should hold valve closed. If
air pressure does not hold valve closed, check for damaged or bent
valve. Cylinder head must be removed for service.
Using valve spring compressor, compress valve springs. Remove
valve locks. Carefully release spring compressor. Remove retainer or
rotator and valve spring. Remove valve stem oil seal.
If oversized valves have been installed, oversized oil seals
must be used. Coat valve stem with engine oil. Install protective
sleeve over end of valve stem. Install new oil seal over valve stem
and seat on valve guide. Remove protective sleeve. Install spring
seat, valve spring and retainer or rotator. Compress spring and
install valve locks. Remove spring compressor. Ensure valve locks
are fully seated.
Install rocker arms or overhead cam components. Tighten all
bolts to specification. Adjust valves if required. Remove adapter.
Install spark plugs, valve cover and gasket.
VALVE SPRING INSTALLED HEIGHT
Valve spring installed height should be checked during
reassembly. Measure height from lower edge of valve spring to the
upper edge. DO NOT include valve spring seat or retainer. Distance
must be within specifications. If valves and/or seats have been
ground, a valve spring shim may be required to correct spring height.
See Fig. 12 .
Fig. 12: Measuring Valve Spring Installed Height - Typical
This Graphic For General Information Only
SEA TS - P O W ER
1999 D odge P ic ku p R 1500
1999 ACCESSORIES & EQUIPMENT
CHRY - Power Seats
Ram Pickup, Ram Van & Ram Wagon
DESCRIPTION & OPERATION
Driver's power seat can be adjusted in 6 different
directions: up, down, forward, back, tilt forward, or tilt rearward.
The power seat system consists of a 6-way switch, motor assembly, seat
adjuster, motor cable, housing and wiring harness.
The power seat system receives battery power through circuit
breaker and a fuse in the Power Distribution Center (PDC). Battery
voltage is available to power seat system at all times. Three
permanent magnet reversible motors are coupled through cables to worm
gear box assemblies located in the seat tracks, providing the various
seat movements.
On Ram Pickup with extended cab (club cab and quad cab),
driver's seat also includes power operated lumbar support. Lumbar
support can be inflated or deflated as needed, using additional
switch. On seats with lumbar support, seat back remains at same
height, while seat cushion raises and lowers. On seats without lumbar
support, entire seat raises and lowers. On all seats, entire seat
moves forward and backward.
TROUBLE SHOOTING
NOTE: Before any testing is attempted, the battery should be fully
charged and all connections and terminals cleaned and
tightened to ensure proper continuity and chassis grounds.
POWER SEAT INOPERATIVE
With dome light on, apply power seat switch in direction of
failure. If dome light dims, power seat may be jamming. Check for
binding or obstructions. If dome light does not dim, check individual
components. See COMPONENT TESTS.
COMPONENT TESTS
HARNESS VOLTAGE TEST
NOTE: This test will determine whether or not voltage is continuous
through body harness to power seat switch.
1) Remove power seat switch from mounting position and
disconnect switch from wiring harness. See POWER SEAT SWITCH under
REMOVAL & INSTALLATION.
2) Connect test light lead to ground terminal (Black wire on
Ram Van and Ram Wagon; Black/Orange wire on Ram Pickup) at power seat
switch harness connector. Using test light, probe power supply wire
(Red/Light Blue wire) at power seat switch harness connector.
3) If test light comes on, power and ground circuits to power
seat switch are good. If test light does not come on, check ground
circuit. See WIRING DIAGRAMS. Repair as necessary. If ground circuit
is okay, check power supply. See CIRCUIT BREAKER. Check ground circuit
for continuity.
