Chrysler 1998 Voyager Service Manual page 1066

9 - 16 2.4L ENGINE
DESCRIPTION AND OPERATION (Continued)
sealing and a chrome plated taper faced intermediate
ring for additional cylinder pressure control. There
are also standard oil control rings.
CYLINDER HEAD: Features a Dual Over Head
Camshaft (DOHC) 4 valves per cylinder cross flow
design. The valves are arranged in two inline banks,
with the ports of the bank of two intake valves per
cylinder facing toward the radiator side of engine
and ports of the bank of two exhaust valves per cyl-
inder facing toward the dash panel. Incorporates
powder metal valve guides and seats. Integral oil gal-
leys within the cylinder head supplies oil to the
hydraulic lash adjusters, camshaft and valve mecha-
nisms.
CAMSHAFTS: The nodular iron camshafts have
six bearing journals and 2 cam lobes per cylinder.
Flanges at the rear journals control camshaft end
play. Provision for cam position sensor is located on
the intake camshaft at the rear of cylinder head. A
hydrodynamic oil seal is used for oil control at the
front of the camshaft.
VALVES: 4 valves per cylinder are actuated by
roller cam followers which pivot on stationary
hydraulic lash adjusters. All valves have 6 mm diam-
eter chrome plated valve stems. The valve sizes are
34.8 mm (1.370 inch.) diameter intake valves and
30.5 mm (1.20 inch.) diameter exhaust valves. Viton
rubber valve stem seals are integral with the spring
seats. Valve springs, spring retainers, and locks are
conventional.
INTAKE MANIFOLD: The intake manifold is a
two piece aluminum casting, attached to the cylinder
head with ten screws. This long branch fan design
enhances low and midspeed torque, while minimizing
undesirable inlet noise.
EXHAUST MANIFOLD: The exhaust manifold is
made of cast iron for strength and high tempera-
tures.
ENGINE LUBRICATION: Refer to Group 0
Lubrication and Maintenance for recommended oil to
be used in various engine application. System is full
flow filtration, pressure feed type. The oil pump is
mounted in the front engine cover and driven by the
crankshaft. Pressurized oil is then routed through
the main oil gallery, running the length of the cylin-
der block, supplying main and rod bearings with fur-
ther routing. Pistons are lubricated from rod bearing
throw off and lubricating slots on the connecting rod
assemblies. Camshaft and valve mechanisms are
lubricated from a full length cylinder head oil gallery
supplied from the crankcase main oil gallery.
DIAGNOSIS AND TESTING
CHECKING ENGINE OIL PRESSURE
(1) Remove oil pressure sending unit and install
gauge assembly C-3292.
(2) Run engine until thermostat opens.
CAUTION: If oil pressure is 0 at idle, Do Not Run
engine at 3000 RPM
(3) Oil Pressure: Curb Idle 25 kPa (4 psi) mini-
mum 3000 RPM 170/550 kPa (25/80 psi).
(4) If oil pressure is 0 at idle. Shut off engine,
check for pressure relief valve stuck open or a
clogged oil pickup screen.
SERVICE PROCEDURES
FITTING PISTONS
Piston and cylinder wall must be clean and dry.
Piston diameter should be measured 90 degrees to
piston pin about 14 mm (9/16 inch.) from the bottom
of the skirt as shown in (Fig. 3). Cylinder bores
should be measured halfway down the cylinder bore
and transverse to the engine crankshaft center line
shown in (Fig. 2). Refer to Cylinder Bore and Piston
Specification Chart.
Correct piston to bore clearance must be estab-
lished in order to assure quiet and economical oper-
ation.
Chrysler engines use pistons designed specifically
for each engine model. Clearance and sizing locations
vary with respect to engine model.
NOTE: Pistons and cylinder bores should be mea-
sured at normal room temperature, 70°F (21°C).
FITTING PISTON RINGS
(1) Wipe cylinder bore clean. Insert ring and push
down with piston to ensure it is square in bore. The
ring gap measurement must be made with the ring
positioning at least 12 mm (0.50 inch) from bottom of
cylinder bore. Check gap with feeler gauge (Fig. 4).
Refer to specification in Piston Ring Specification
Chart.
(2) Check piston ring to groove side clearance (Fig.
5). Refer to specification in Piston Ring Specification
Chart.
NS