Page 1065 of 1938

BALANCE SHAFTS
Balance shaft lubrication is provided through an
oil passage from the number 1 main bearing cap
through the balance shaft carrier support leg. This
passage directly supplies oil to the front bearings and
internal machined passages in the shafts that routes
oil from front to rear shaft bearing journals
SPLASH LUBRICATION
Oil returning to the pan from pressurized compo-
nents supplies lubrication to the valve stems. Cylin-
der bores and wrist pins are splash lubricated from
directed slots on the connecting rod thrust collars.
ENGINE COMPONENTS
BALANCE SHAFTS:2.4L engines are equipped
with two balance shafts installed in a carrier
attached to the lower crankcase. The shafts intercon-
nect through gears to rotate in opposite directions.These gears are driven by a short chain from the
crankshaft, to rotate at two times crankshaft speed.
This counterbalances certain engine reciprocating
masses.
CYLINDER BLOCK AND BEDPLATE ASSEM-
B LY:A closed deck design is used for cooling and
weight reduction with water pump molded into the
block. Nominal wall thickness is 4.5 mm. The bed-
plate incorporates main bearing caps. Rear seal
retainer is integral with the block.
CRANKSHAFT:A nodular cast iron crankshaft is
used. The engine has 5 main bearings, with number
3 flanged to control thrust. The 60 mm diameter
main and 50 mm diameter crank pin journals (all)
have undercut fillets that are deep rolled for added
strength. To evenly distribute bearing loads and min-
imize internal stress, 8 counterweights are used.
Hydrodynamic seals provide end sealing, where the
crankshaft exits the block. Anaerobic gasket material
is used for parting line sealing in the block. A sin-
tered powder metal timing belt sprocket is mounted
on the crankshaft nose. This sprocket provides
motive power; via timing belt to the camshaft sprock-
ets (providing timed valve actuation) and to the
water pump.
PISTONS:There is provisions for free wheeling
valve train. Piston has a unique height. All engines
use pressed in piston pins to attach forged powder
metal connecting rods. Incorporate hex head cap
screw threaded into the connecting rod. Piston and
Rods are serviced as a assembly.
PISTONS RINGS:The piston rings include a
molybdenum faced top ring for reliable compression
EngineÐ2.4L
Fig. 1 Engine Identification
NS2.4L ENGINE 9 - 15
DESCRIPTION AND OPERATION (Continued)
Page 1066 of 1938

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 Idle25 kPa (4 psi) mini-
mum3000 RPM170/550 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, 70ÉF (21ÉC).
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.
9 - 16 2.4L ENGINENS
DESCRIPTION AND OPERATION (Continued)
Page 1067 of 1938

PISTON RINGSÐINSTALLATION
(1) Install rings with manufacturers I.D. mark fac-
ing up, to the top of the piston (Fig. 6).
CAUTION: Install piston rings in the following
order:
Fig. 2 Checking Cylinder Bore Size
CYLINDER BORE AND PISTON
SPECIFICATION CHART
Standard Bore Maximum
Out-Of-RoundMaximum
Taper
87.5 mm 0.051 mm 0.051 mm
(3.445 in.) (0.002 in.) (0.002 in.)
Standard Piston Size
87.450 - 87.468 mm (3.4434 - 3.4441 in.)
Piston To Bore Clearance
0.024 - 0.057 mm (0.0009 - 0.0022 in.)
Note: Measurements taken at Piston Size Location.
Fig. 3 Piston Measurement
Fig. 4 Piston Ring Gap
PISTON RING SPECIFICATION CHART
Ring Position Ring Gap Wear Limit
Upper Ring 0.025 to 0.51 mm
(0.0098 to 0.020 in.)0.8 mm
(0.031 in.)
Intermediate
Ring0.23 to 0.48 mm
(0.009 to 0.018 in.)0.8 mm
(0.031 in.)
Oil Control
Ring0.25 to 0.64 mm
(0.0098 to 0.025 in.)1.0 mm
(0.039 in.)
Ring Position Groove Clearance Max.
Clearance
Upper Ring 0.030 to 0.080 mm
(0.0011 to 0.0031 in.)0.10 mm
(0.004 in.)
Intermediate
Ring0.025 to 0.065 mm
(0.0010 to 0.0026 in.)0.10 mm
(0.004 in.)
Oil Control Ring - Three Piece. Oil Ring Side Rails
Must Be Free To Rotate After Assembly.
Fig. 5 Piston Ring Side Clearance
NS2.4L ENGINE 9 - 17
SERVICE PROCEDURES (Continued)
Page 1068 of 1938

a. Oil ring expander.
b. Upper oil ring side rail.
c. Lower oil ring side rail.
d. No. 2 Intermediate piston ring.
e. No. 1 Upper piston ring.
(2) Install the side rail by placing one end
between the piston ring groove and the expander.
Hold end firmly and press down the portion to be
installed until side rail is in position.Do not use a
piston ring expander(Fig. 7).
(3) Install upper side rail first and then the lower
side rail.
(4) Install No. 2 piston ring and then No. 1 piston
ring.
(5) Position piston ring end gaps as shown in (Fig.
8).
(6) Position oil ring expander gap at least 45É
from the side rail gaps butnoton the piston pin cen-
ter or on the thrust direction. Staggering ring gap is
important for oil control.FITTING CONNECTING ROD BEARINGS
Engine connecting rod bearing clearances can be
determined by use of Plastigage or equivalent. The
following is the recommended procedure for the use
of Plastigage:
(1) Rotate the crankshaft until the connecting rod
to be checked is at the bottom of its stroke.
(2) Remove oil film from surface to be checked.
Plastigage is soluble in oil.
(3) Place a piece of Plastigage across the entire
width of the bearing shell in the bearing cap approx-
imately 6.35 mm (1/4 in.) off center and away from
the oil hole (Fig. 9). In addition, suspect areas can be
checked by placing plastigage in the suspect area.
(4) Before assembling the rod cap with Plastigage
in place, the crankshaft must be rotated until the
connecting rod being checked starts moving toward
the top of the engine. Only then should the cap be
assembled and torqued to specifications.Do not
rotate the crankshaft while assembling the cap
or the Plastigage may be smeared, giving inac-
curate results.
(5) Remove the bearing cap and compare the width
of the flattened Plastigage (Fig. 9) with the metric
Fig. 6 Piston Ring Installation
Fig. 7 Installing Side Rail
Fig. 8 Piston Ring End Gap Position
Fig. 9 Measuring Plastigage Width
9 - 18 2.4L ENGINENS
SERVICE PROCEDURES (Continued)
Page 1069 of 1938

scale provided on the package. Locate the band clos-
est to the same width. This band shows the amount
of clearance in thousandths of a millimeter. Differ-
ences in readings between the ends indicate the
amount of taper present. Record all readings taken.
Refer to Engine Specifications.Plastigage gener-
ally is accompanied by two scales. One scale is
in inches, the other is a metric scale.
(6) Plastigage is available in a variety of clearance
ranges. The 0.025-0.076 mm (.001-.003 in.) is usually
the most appropriate for checking engine bearing
proper specifications.
FITTING MAIN BEARINGS
Refer to the Engine General Information Section
for Measuring Main Bearings. For Crankshaft speci-
fications refer to Crankshaft Specification Chart.
CRANKSHAFT MAIN BEARINGS
The crankshaft is supported in five main bearings.
All upper and lower bearing shells in the crankcase
have oil grooves. The number three lower main
thrust bearing is plain. Crankshaft end play is con-
trolled by a flanged bearing on the number three
main bearing journal (Fig. 10).
Upper and lower Number 3 bearing halves are
flanged to carry the crankshaft thrust loads and are
NOT interchangeable with any other bearing halves
in the engine (Fig. 10). All bearing cap bolts removed
during service procedures are to be cleaned and oiled
before installation. Bearing shells are available in
standard and the following undersized: 0.025 mm
(0.001 in.) and 0.250 mm (0.010 in.). Never install an
undersize bearing that will reduce clearance below
specifications.
MAIN BEARING INSTALLATION
(1) Install the main bearing shells with the lubri-
cation groove in the cylinder block (Fig. 11).
(2) Make certain oil holes in block line up with oil
holes in bearings. Bearing tabs must seat in the
block tab slots.
CAUTION: Do not get oil on the bedplate mating
surface. It will may effect the sealer ability to seal
the bedplate to cylinder block.
(3) Oil the bearings and journals and install
crankshaft.
CAUTION: Use only the specified anaerobic sealer
on the bedplate or damage may occur to the
engine. Ensure that both cylinder block and bed-
plate surfaces are clean.
CRANKSHAFT SPECIFICATION CHART
Crankshaft End-Play
New Part: 0.09 - 0.24 mm (0.0035 - 0.0094 in.)
Wear Limit: 0.37 mm (0.015 in.)
Main Bearing Clearance
New Part: 0.018 - 0.058 mm (0.0007 - 0.0023 in.)
Connecting Rod Bearing Clearance
New Part: 0.025 - 0.071 mm (0.001 - 0.003 in.)
Wear Limit: 0.075 mm (0.003 in.)
Crankshaft Journal Sizes
Main Bearing Journal Diameter
Standard 60.00060.008 mm (2.362260.0003 in.)
1 st Undersize 59.97560.008 mm (2.36160.0003 in.)
Connecting Rod Journals
Standard 49.99260.008 mm (1.96860.0003 in.)
1 st Undersize 49.96760.008 mm (1.96760.0003 in.)
Fig. 10 Main Bearing Identification
Fig. 11 Installing Main Bearing Upper Shell
NS2.4L ENGINE 9 - 19
SERVICE PROCEDURES (Continued)
Page 1070 of 1938

(4) Apply 1.5 to 2.0 mm (0.059 to 0.078 in.) bead
of anaerobic sealer MopartTorque Cure Gasket
Maker to cylinder block as shown in (Fig. 12).
(5) Install lower main bearings into main bearing
cap/bedplate. Make certain the bearing tabs are
seated into the bedplate slots. Install the main bear-
ing/bedplate into engine block.
(6) Before installing bolts, lubricate the threads
with clean engine oil, wipe off any excess oil.
(7) Install main bearing bedplate to engine block
bolts 11, 17 and 20 finger tight. Tighten these bolts
down together until the bedplate contacts the cylin-
der block.
(8) To ensure correct thrust bearing alignment,
perform the following steps:
²Step 1: Rotate crankshaft until number 4 piston
is at TDC.
²Step 2: Move crankshaft rearward to limits of
travel.²Step 3: Then, move crankshaft forward to limits
of travel.
²Step 4: Wedge an appropriate tool between the
rear of the cylinder block(NOT BED PLATE)and
the rear crankshaft counterweight. This will hold the
crankshaft in it's furthest forward position.
²Step 5: Install and tighten bolts (1 ± 10) in
sequence shown in (Fig. 13) to 41 N´m (30 ft. lbs.).
²Step 6: Remove wedge tool used to hold crank-
shaft.
(9) Tighten bolts (1 ± 10) again to 41 N´m (30 ft.
lbs.) + 1/4 turn in sequence shown in (Fig. 13).
(10) Install main bearing bedplate to engine block
bolts (11 through 20), and torque each bolt to 28 N´m
(20 ft. lbs.) in sequence shown in (Fig. 13).
(11) After the main bearing bedplate is installed,
check the crankshaft turning torque. The turning
torque should not exceed 5.6 N´m (50 in. lbs.).
CRANKSHAFT END PLAY
(1) Mount a dial indicator to front of engine, locat-
ing probe on nose of crankshaft (Fig. 14).
(2) Move crankshaft all the way to the rear of its
travel.
(3) Zero the dial indicator.
(4) Move crankshaft all the way to the front and
read the dial indicator. Refer to Crankshaft Specifi-
cation Chart for end-play specification.
Fig. 12 Main Bearing Caps/Bedplate Sealing
Fig. 13 Main Bearing Caps/Bedplate Torque
SequenceFig. 14 Checking Crankshaft End PlayÐTypical
CRANKSHAFT SPECIFICATION CHART
Crankshaft End-Play
New Part: 0.09 - 0.24mm
(0.0035 - 0.0094 in.)
Wear Limit: 0.37 mm
(0.015 in.)
9 - 20 2.4L ENGINENS
SERVICE PROCEDURES (Continued)
Page 1071 of 1938

OPTIONAL CRANKSHAFT END PLAY CHECK
(1) Move crankshaft all the way to the rear of its
travel using a lever inserted between a main bearing
cap and a crankshaft cheek, using care not to dam-
age any bearing surface.DO NOTloosen main bear-
ing cap.
(2) Use a feeler gauge between number three
thrust bearing and machined crankshaft surface to
determine end play.
VALVE SERVICE RECONDITION
VALVE REMOVAL
(1) With cylinder head removed, compress valve
springs using Special Tool C-3422-B or equivalent.
(2) Remove valve retaining locks, valve spring
retainers, valve stem seals and valve springs.
(3) Before removing valves,remove any burrs
from valve stem lock grooves to prevent dam-
age to the valve guides.Identify valves to insure
installation in original location.
VALVE INSPECTION
(1) Clean valves thoroughly and discard burned,
warped and cracked valves.
(2) Measure valve stems for wear. Measure stem
about 60 mm beneath the valve lock grooves.
(3) If valve stems are worn more than 0.05 mm
(0.002 in.), replace valve.
VALVE GUIDES
(1) Remove carbon and varnish deposits from
inside of valve guides with a reliable guide cleaner.
(2) Using a small hole gauge and a micrometer,
measure valve guides in 3 places top, middle and bot-
tom (Fig. 15). Refer to Valve Guide Specification
Chart. Replace guides if they are not within specifi-
cation.
(3) Check valve guide height (Fig. 16).
TESTING VALVE SPRINGS
(1) Whenever valves have been removed for inspec-
tion, reconditioning or replacement, valve springs
should be tested. As an example, the compression
length of the spring to be tested is 33.34 mm (1 5/16inches). Turn tool table until surface is in line with
the 33.34 mm (1 5/16 in.) mark on the threaded stud
and the zero mark on the front. Place spring over
stud on the table and lift compressing lever to set
tone device (Fig. 17). Pull on torque wrench until
ping is heard. Take reading on torque wrench at this
instant. Multiply this reading by two. This will give
the spring load at test length. Fractional measure-
ments are indicated on the table for finer adjust-
ments. Discard the springs that do not meet
specifications. The Following specifications apply to
both intake and exhaust valve springs;
²Valve Closed Nominal TensionÐ 76 lbs. @ 38.0
mm (1.50 in.)
²Valve Open Nominal TensionÐ 136 lbs. @ 29.75
mm (1.17 in.)
(2) Inspect each valve spring for squareness with a
steel square and surface plate, test springs from both
ends. If the spring is more than 1.5 mm (1/16 inch)
out of square, install a new spring.
REFACING VALVES AND VALVE SEATS
(1) The intake and exhaust valve seats and valve
face have a 45 and a 45 1/2 degree angles.
Fig. 15 Checking Wear on Valve GuideÐTypical
VALVE GUIDE SPECIFICATION CHART
Valve Guide Diameter
Intake and
Exhaust Valve:5.975 - 6.000 mm
(0.2352 - 0.2362 in.)
Valve Guide Clearance
New Service
Limit
Intake Valve: 0.048 - 0.066 mm
(0.0018 - 0.0025 in.)
0.25 mm
(0.010 in.)
Exhaust Valve: 0.0736 - 0.094 mm
(0.0029 - 0.0037 in.)
Fig. 16 Valve Guide Height
NS2.4L ENGINE 9 - 21
SERVICE PROCEDURES (Continued)
Page 1072 of 1938

(2) Inspect the remaining margin after the valves
are refaced (Fig. 18). Intake valves with less than 1.2
mm (3/64 inch.) margin and Exhaust valves with less
than 0.9 mm (1/32 inch.) margin should be discarded.
(3) 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.
(4) Measure the concentricity of valve seat and
valve guide using a valve seat runout dial indicator.
Total runout should not exceed. 0.051 mm (0.002
inch.) (total indicator reading).
(5) Inspect the valve seat with Prussian blue to
determine where the valve contacts the seat. To do
this, coat valve seatLIGHTLYwith 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 top edge of the valve face, lower valve seat
with a 15 degrees stone. If the blue is transferred to
the bottom edge of valve face raise valve seat with a
65 degrees stone.²Intake valve seat diameter is 34.37 34.63 mm
(1.158 1.363 inch.)
²Exhaust valve seat diameter is 29.37 29.63 mm
(1.156 1.166 inch.)
(6) Valve seats which are worn or burned can be
reworked, provided that correct angle and seat width
are maintained. Otherwise the cylinder head must be
replaced.
(7) When seat is properly positioned the width of
intake and exhaust seats should be 0.9 to 1.3 mm
(0.35 to 0.051 inch.) (Fig. 19).
(8) Check valve tip height dimensions A after
grinding the valve seats or faces (Fig. 20). Grind
valve tip to 47.99 mm (1.889 in.) for exhaust valve
and 48.04 mm (1.891 in.) for intake valve when
installed in the head. The valve tip chamfer may
Fig. 17 Testing Valve Springs
Intake and Exhaust Valves
VALVE SPECIFICATION CHART
Face Angle
Intake and Exhaust: 44.5É-45É
Head Diameter
Intake: 34.67 - 34.93 mm
(1.364 - 1.375 in.)
Exhaust: 30.37 - 30.63 mm
(1.195 - 1.205 in.)
Length (Overall)
Intake: 112.76 - 113.32 mm
(4.439 - 4.461 in.)
Exhaust: 109.59 - 110.09 mm
(4.314 - 4.334 in.)
Stem Diameter
Intake: 5.934 - 5.952 mm
(0.2337 - 0.2344 in.)
Exhaust: 5.906 - 5.924 mm
(0.2326 - 0.2333 in.)
Valve Margin
Intake: 1.285 - 1.615 mm
(0.050 - 0.063 in.)
Exhaust: 0.985 - 1.315 mm
(0.038 - 0.051 in.)
Fig. 18 Refacing Intake and Exhaust Valves
9 - 22 2.4L ENGINENS
SERVICE PROCEDURES (Continued)