CYLINDER HEAD
REMOVAL
(1) Perform fuel system pressure release proce-
durebefore attempting any repairs.Refer to
Group 14, Fuel System for procedure.
(2) Disconnect negative battery cable. Drain cool-
ing system. Refer to Group 7, Cooling System for pro-
cedure.
(3) Remove air cleaner and disconnect all vacuum
lines, electrical wiring and fuel lines from throttle
body.
(4) Remove throttle linkage. Refer to Group 14,
Fuel System for procedures
(5) Remove accessory drive belts. Refer to Group
7, Cooling System for procedure.
(6) Remove power brake vacuum hose from intake
manifold.
(7) Raise vehicle and remove exhaust pipe from
manifold.(8) Remove power steering pump assembly and
set aside.
(9) Disconnect coil pack wiring connector and
remove coil pack and plug wires from engine.
(10) Remove cam sensor and fuel injectors wiring
connectors.
(11) Remove timing belt and camshaft sprocket.
Refer to procedure outlined in this section.
(12) Remove timing belt idler pulley and rear tim-
ing belt cover.
(13) Remove cylinder head cover using procedure
outlined in this section.
(14) Remove camshafts and cam followers. Refer to
procedures outlined in this section for procedures.
(15) Remove cylinder head bolts and remove cyl-
inder head from engine block.
(16) Inspect and clean cylinder head. Refer to
Cleaning and Inspection outlined in this section for
procedures.
INSTALLATION
NOTE: The Cylinder head bolts should be exam-
ined BEFORE reuse. If the threads are necked
down, the bolts should be replaced (Fig. 49).
Necking can be checked by holding a scale or
straight edge against the threads. If all the threads
do not contact the scale the bolt should be replaced.
(1) Before installing the bolts, the threads should
be coated with engine oil.
(2) Tighten the cylinder head bolts in the
sequence shown in (Fig. 50). Using the 4 step torque
turn method, tighten according to the following val-
ues:
²First All to 34 N´m (25 ft. lbs.)
²Second All to 68 N´m (50 ft. lbs.)
²Third All to 68 N´m (50 ft. lbs.)
CAUTION: Do not use a torque wrench for the fol-
lowing step.
²Fourth Turn an additional 1/4 Turn,
(3) Install camshafts and cam followers. Refer to
procedures outlined in this section for procedures.
Fig. 47 Valve SpringÐRemoval/Installation
Fig. 48 Valve Stem Seal/Valve Spring Seat
Fig. 49 Checking Bolts for Stretching (Necking)
9 - 34 2.4L ENGINENS
REMOVAL AND INSTALLATION (Continued)
(4) Install cylinder head cover using procedure out-
lined in this section.
(5) Install rear timing belt cover and timing belt
idler pulley.
(6) Install timing belt and camshaft sprocket.
Refer to procedure outlined in this section.
(7) Install cam sensor and fuel injectors wiring
connectors.
(8) Install coil pack and plug wires onto the
engine. Connect coil pack wiring connector.
(9) Install power steering pump assembly.
(10) Raise vehicle and install the exhaust pipe to
the manifold.
(11) Install power brake vacuum hose to the intake
manifold.
(12) Install accessory drive belts. Refer to Group 7,
Cooling System for procedure.
(13) Install throttle linkage. Refer to Group 14,
Fuel System for procedures.
(14) Install air cleaner and connect all vacuum
lines, electrical wiring and fuel lines to the throttle
body.
(15) Fill cooling system. Refer to Group 7, Cooling
System for procedure. Connect negative battery
cable.
VALVES AND VALVE SPRINGS
REMOVAL
(1) With cylinder head removed, compress valve
springs using a universal valve spring compressor.
(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.
(4) Inspect and clean the valves. Refer to Cleaning
and Inspection outlined in this section for procedure.
INSTALLATION
(1) Coat valve stems with clean engine oil and
insert in cylinder head.
(2) Install new valve stem seals on all valves
using a valve stem seal tool (Fig. 51). The valve stem
seals should be pushed firmly and squarely over
valve guide.
CAUTION: When oversize valves are used, the cor-
responding oversize valve seal must also be used.
Excessive guide wear may result if oversize seals
are not used with oversize valves.
(3) Install valve springs and retainers. Compress
valve springs only enough to install locks, taking
care not to misalign the direction of compression.
Nicked valve stems may result from misalignment of
the valve spring compressor.
CAUTION: When depressing the valve spring
retainers with valve spring compressor the locks
can become dislocated. Ensure both locks are in
the correct location after removing tool.
(4) Check the valve spring installed height B after
refacing the valve and seat (Fig. 52). Make sure mea-
surements are taken from top of spring seat to the
bottom surface of spring retainer. If height is greater
than 38.75 mm (1.525 in.), install a .762 mm (0.030
in.) spacer under the valve spring seat to bring
spring height back within specification.
Fig. 50 Cylinder Head Tightening Sequence
Fig. 51 Valve Stem Oil Seal Tool
NS2.4L ENGINE 9 - 35
REMOVAL AND INSTALLATION (Continued)
(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 per-
form the following steps:
²Step 1: Rotate crankshaft until number 4 pis-
ton is at TDC.
²Step 2: Move crankshaft rearward to limits of
travel.
²Step 3: Then, move crankshaft forward to lim-
its of travel.
²Step 4: Wedge an appropraite 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. 84) to 41 Nzm (30 ft. lbs.).
²Step 6: Remove wedge tool used to hold crank-
shaft.
(9) Tighten bolts (1-10) again to 41 Nzm (30 ft. lbs)
+ 1/4 turn in sequence shown in (Fig. 84).
(10) Install main bearing bedplate to engine block
bolts (11-20), and torque each bolt to 28 Nzm (20 ft.
lbs.) in sequence shown in (Fig. 84).
(11) After the main bearing bedplate is installed,
check the crankshaft turning torque. The turning
torque should not exceed 5.6 Nzm (50 in. lbs.).
OIL FILTER
CAUTION: When servicing the oil filter avoid
deforming the filter can by installing the remove/in-
stall tool band strap against the can to base lock
seam. The lock seam joining the can to the base is
reinforced by the base plate.(1) Turn counterclockwise to remove.
(2) To install, lubricate new filter gasket. Check
filter mounting surface. The surface must be smooth,
flat and free of debris or old pieces of rubber. Screw
filter on until the gasket contacts base. Tighten to 21
N´m (15 ft. lbs.).
OIL PUMP
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove Timing Belt. Refer to procedure out-
lined in this section.
(3) Remove Oil Pan. Refer to procedure outlined in
this section.
(4) Remove Crankshaft Sprocket using Special Tool
6793 and insert C-4685-C2 (Fig. 85).
(5) Remove oil pick-up tube.
(6) Remove oil pump, (Fig. 86) and front crank-
shaft seal.
Fig. 85 Crankshaft SprocketÐRemoval
NS2.4L ENGINE 9 - 47
REMOVAL AND INSTALLATION (Continued)
(2) Before installing the ring compressor, make
sure the oil ring expander ends are butted and the
rail gaps located as shown in (Fig. 92). As viewed
from top.
(3) Immerse the piston head and rings in clean
engine oil, slide the ring compressor, over the piston
(Fig. 93).Be sure position of rings does not
change during this operation.
(4) The directional stamp on the piston should
face toward the front of the engine (Fig. 90).
(5) Rotate crankshaft so that the connecting rod
journal is on the center of the cylinder bore. Insert
rod and piston assembly into cylinder bore and guide
rod over the crankshaft journal.
(6) Tap the piston down in cylinder bore, using a
hammer handle. At the same time, guide connecting
rod into position on connecting rod journal.
NOTE: The rod bearing bolts should not be reused.
(7) Before installing theNEWbolts the threads
should be coated with clean engine oil.(8) Install each bolt finger tight than alternately
torque each bolt to assemble the cap properly.
CAUTION: Do not use a torque wrench for second
part of last step.
(9) Tighten the bolts to 27 N´m PLUS 1/4 turn (20
ft. lbs. PLUS 1/4 turn).
(10) Using a feeler gauge, check connecting rod
side clearance (Fig. 94).
DISASSEMBLY AND ASSEMBLY
OIL PUMP
DISASSEMBLY
(1) To remove the relief valve, proceed as follows:
(a) Remove the threaded plug and gasket from
the oil pump (Fig. 95).
(b) Remove spring and relief valve.
(2) Remove oil pump cover screws, and lift off
cover.
(3) Remove pump rotors.
Fig. 92 Piston Ring End Gap Position
Fig. 93 PistonÐInstallation
Fig. 94 Checking Connecting Rod Side Clearance
Fig. 95 Oil Pressure Relief Valve
9 - 50 2.4L ENGINENS
REMOVAL AND INSTALLATION (Continued)
(4) Wash all parts in a suitable solvent and
inspect carefully for damage or wear.
ASSEMBLY
(1) Assemble pump, using new parts as required.
Install the inner rotor with chamfer facing the
cast iron oil pump cover.
(2) Prime oil pump before installation by filling
rotor cavity with engine oil.
(3) Install cover and tighten screws to 12 N´m
(105 in. lbs.).
CAUTION: Oil pump pressure relief valve must be
installed as shown in (Fig. 95) or serious damage
may occur.
(4) Install relief valve, spring, gasket and cap as
shown in (Fig. 95). Tighten cap to 41 N´m (30 ft. lbs.)
CLEANING AND INSPECTION
CYLINDER HEAD
CLEANING
Remove all gasket material from cylinder head and
block. Be careful not to gouge or scratch the alumi-
num head sealing surface.
INSPECTION
(1) Cylinder head must be flat within 0.1 mm
(0.004 inch) (Fig. 96).
(2) Inspect camshaft bearing journals for scoring.
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. 97). Refer to Valve Guide SpecificationChart. Replace guides if they are not within specifi-
cation.
(3) Check valve guide height (Fig. 98).
VALVE AND VALVE SPRING
VALVES
(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.
Fig. 96 Checking Cylinder Head Flatness
Fig. 97 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. 98 Valve Guide Height
NS2.4L ENGINE 9 - 51
DISASSEMBLY AND ASSEMBLY (Continued)
(3) If valve stems are worn more than 0.05 mm
(.002 in.), replace valve.
VALVE SPRINGS
(1) Whenever valves have been removed for
inspection, reconditioning or replacement, valve
springs should be tested for correct tension. Discard
the springs that do not meet specifications. The fol-
lowing specifications apply to both intake and
exhaust valves 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.
CRANKSHAFT
The crankshaft journals should be checked for
excessive wear, taper and scoring (Fig. 99). Limits of
taper or out-of-round on any crankshaft journals
should be held to .025 mm (.001 inch). Journal grind-
ing should not exceed .305 mm (.012 inch) under the
standard journal diameter.DO NOTgrind thrust
faces of Number 3 main bearing.DO NOTnick
crank pin or bearing fillets. After grinding, remove
rough edges from crankshaft oil holes and clean out
all passages.
CAUTION: With the nodular cast iron crankshafts
used it is important that the final paper or cloth pol-
ish after any journal regrind be in the same direc-
tion as normal rotation in the engine.
OIL PUMP
(1) Clean all parts thoroughly. Mating surface of
the oil pump should be smooth (Fig. 100). Replace
pump cover if scratched or grooved.(2) Lay a straightedge across the pump cover sur-
face (Fig. 101). If a 0.025 mm (0.001 in.) feeler gauge
can be inserted between cover and straight edge,
cover should be replaced.
(3) Measure thickness and diameter of outer rotor.
If outer rotor thickness measures 9.40 mm (0.370 in.)
or less (Fig. 102), or if the diameter is 79.95 mm
(3.148 in.) or less, replace outer rotor.
(4) If inner rotor measures 9.40 mm (0.370 in.) or
less replace inner rotor (Fig. 103).
(5) Slide outer rotor into pump housing, press to
one side with fingers and measure clearance between
rotor and housing (Fig. 104). If measurement is 0.39
mm (0.015 in.) or more, replace housing only if outer
rotor is in specification.
(6) Install inner rotor into pump housing. If clear-
ance between inner and outer rotors (Fig. 105) is
0.203 mm (0.008 in.) or more, replace both rotors.
(7) Place a straightedge across the face of the
pump housing, between bolt holes. If a feeler gauge
of 0.102 mm (0.004 in.), or more can be inserted
Fig. 99 Crankshaft Journal Measurements
Fig. 100 Oil Pump
Fig. 101 Checking Oil Pump Cover Flatness
9 - 52 2.4L ENGINENS
CLEANING AND INSPECTION (Continued)
3.0L ENGINE
INDEX
page page
DESCRIPTION AND OPERATION
ENGINE COMPONENTS.................. 61
ENGINE IDENTIFICATION NUMBER......... 61
ENGINE LUBRICATION................... 61
DIAGNOSIS AND TESTING
CHECKING ENGINE OIL PRESSURE......... 62
SERVICE PROCEDURES
AUTO LASH ADJUSTER................... 62
CHECKING CRANKSHAFT END PLAY........ 65
FITTING CONNECTING ROD BEARINGS...... 63
FITTING MAIN BEARING.................. 63
VALVE SERVICE RECONDITION............ 66
REMOVAL AND INSTALLATION
CAMSHAFT SEAL....................... 72
CAMSHAFT............................ 71
CRANKSHAFT.......................... 81
CYLINDER HEAD COVER................. 70
CYLINDER HEAD........................ 73
ENGINE ASSEMBLY...................... 69
ENGINE MOUNTS....................... 68
FRONT CRANKSHAFT OIL SEAL............ 83OIL FILTER AND ADAPTOR................ 84
OILPAN ............................... 77
OIL PUMP............................. 84
PISTON AND CONNECTING ROD........... 78
REAR CRANKSHAFT SEAL................ 83
ROCKER ARMS......................... 72
TIMING BELT........................... 75
DISASSEMBLY AND ASSEMBLY
ROCKER ARMS AND SHAFTS.............. 85
CLEANING AND INSPECTION
CYLINDER BORE........................ 87
CYLINDER HEAD........................ 86
OIL PUMP............................. 87
TIMING BELT........................... 86
ADJUSTMENTS
ENGINE MOUNTS....................... 88
SPECIFICATIONS
3.0L ENGINE........................... 89
TORQUE CHART 3.0L.................... 90
SPECIAL TOOLS
3.0L ENGINE........................... 91
DESCRIPTION AND OPERATION
ENGINE IDENTIFICATION NUMBER
The engine identification number is located on the
rear of the cylinder block just below the cylinder
head (Fig. 1).
ENGINE LUBRICATION
System is a full flow filtration, pressure feed type.
The oil pump is mounted behind the timing belt
cover. The pump inner rotor is driven by the crank-
shaft. The engine oil pan contains a baffle plate to
control oil level fluctuation during engine operation.
ENGINE COMPONENTS
BLOCK:The cylinder block is a light weight
design created by reducing thickness in many parts
and a short 10 mm (3/8 in.) block skirt. High rigidity
is provided with ribs cast in the outer wall, a full
length water jacket, and a mono-block or beam type,
main bearing cap. This single unit four bearing cap
is designed to control vibration of the cylinder block
partition walls.
CRANKSHAFT:A six throw, five weight crank-
shaft is supported by four main bearings with num-
ber three being the thrust bearing. The six separate
connecting rod throws pins reduce torque fluctua-tions while a torsional vibration damper is used to
control torsion caused vibration of the crankshaft.
Rubber lipped seals are used at front and rear. The
Fig. 1 Engine Identification
NS3.0L ENGINE 9 - 61
front seal is retained in the oil pump case and the
rear is retained in a block-mounted housing.
PISTONS:Are aluminum alloy with a steel strut,
short height, and thin wall so as to be autothermic
and light weight. The piston head with valve
recesses, in combination with the cylinder head,
forms a compact spherical head with clearance for
total valve lift with pistons at top dead center. The
piston skirt, top and second ring lands are finished to
a tapered roughness for oil retention and high resis-
tance to scuffing. Piston pins, pressed into place, join
the pistons to the connecting rods.
CYLINDER HEAD:The alloy cylinder heads fea-
ture cross-flow type intake and exhaust ports. Valve
guides and inserts are hardened cast iron. Valves of
heat resistance steel are arranged in a V with each
camshaft on center. To improve combustion speed the
chambers are a compact spherical design with a
squish area of approximately 30 percent of the piston
top area. The cylinder heads are common to either
cylinder bank by reversing the direction of installa-
tion.
CAMSHAFTS:Two overhead camshafts provide
valve actuation, one front (radiator side of cylinder
bank) and one rear. The front camshaft is provided
with a distributor drive and is longer. Both cam-
shafts are supported by four bearing journals, thrust
for the front camshaft is taken at journal two and
the rear at journal three. Front and rear camshaft
driving sprockets are interchangeable. The sprockets
and the engine water pump are driven by a single
notched timing belt.
ROCKER ARM SHAFTS:The shafts are retained
by the camshaft bearing journal caps. Four shafts are
used, one for each intake and exhaust rocker arm
assembly on each cylinder head. The hollow shafts
provide a duct for lubricating oil flow from the cylin-
der head to the valve mechanisms.
ROCKER ARMS:Are of light weight die-cast with
roller type follower operating against the cam shaft.
The valve actuating end of the rocker arms are
machined to retain hydraulic lash adjusters, elimi-
nating valve lash adjustment.
VALVES:Are made of heat resistant steel, valve
springs are especially designed to be short. The valve
spring wire cross-section is oval shaped and provides
the same spring tension as longer springs. Valve
spring retainers, locks and seals are conventional.
INTAKE MANIFOLD:The aluminum alloy mani-
fold is a cross type with long runners to improve
inertia. The runners, attaching below at the cylinder
head, also attach above and support an air plenum.
The air plenum chamber absorbs air pulsations cre-
ated during the suction phase of each cylinder.
EXHAUST MANIFOLDS:Both manifolds are a
log style made of ductile cast iron. Exhaust gasses,collected from the front cylinder bank, leave the front
manifold through an end outlet and are fed through
an upper crossover tube to the rear manifold. The
collected exhaust from both manifolds are combined,
and exit to the exhaust pipe through an articulated
joint.
DIAGNOSIS AND TESTING
CHECKING ENGINE OIL PRESSURE
Check oil pressure using gauge at oil pressure
switch location. Oil pressure should be 41 kPa ( 6
psi.) at idle or 241 to 517 kPa (35 to 75 psi.) at 3000
RPM.
(1) Remove pressure sending unit and install oil
pressure gauge. (Fig. 2).
CAUTION: If oil pressure is 0 at idle, Do Not Run
engine at 3000 RPM.
(2) Warm engine at high idle until thermostat
opens.
SERVICE PROCEDURES
AUTO LASH ADJUSTER
The automatic lash adjusters are precision units
installed in machined openings in the valve actuating
ends of the rocker arms. Do not disassemble the auto
lash adjuster.
FUNCTION CHECK
Check auto adjusters for free play by inserting a
small wire through the air bleed hole in the rocker
arm andvery lightlypushing the auto adjuster ball
check down (Fig. 3). While lightly holding the check
ball down move the rocker up and down to check for
free play. If there is no play replace the adjuster.
Fig. 2 Checking Engine Oil Pressure
9 - 62 3.0L ENGINENS
DESCRIPTION AND OPERATION (Continued)