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9 - 216
ENGINE 2.7L DOHC
EXHAUST MANIFOLD (Continued)
REAR EXHAUST MANIFOLD
(1) Disconnect negative battery cable.
(2) Remove throttle body air inlet hose and air
cleaner housing assembly.
(3) Remove bolts attaching EGR tube from exhaust
manifold and EGR valve. Discard gaskets.
(4) Raise vehicle on hoist.
(5) Remove exhaust system from vehicle (Refer to
11 - EXHAUST SYSTEM - REMOVAL).
(6) Remove exhaust cross-under pipe (Refer to 11 -
EXHAUST SYSTEM/CROSS-OVER PIPE - REMOV-
AL).
(7) Remove rear catalytic converter (Refer to 11 -
EXHAUST SYSTEM/CATALYTIC CONVERTER -
REMOVAL).
(8) Disconnect and remove rear upstream oxygen
sensor.
(9) Remove rear exhaust manifold heat shield.
(10) Remove exhaust manifold attaching bolts and
remove manifold.
INSPECTION
(1) Inspect exhaust manifolds for damage or
cracks.
(2) Check manifold flatness.
(3) Inspect the exhaust manifold gasket for obvi-
ous discoloration or distortion.
(4) Check distortion of the cylinder head mounting
surface with a straightedge and thickness gauge.
INSTALLATION
FRONT EXHAUST MANIFOLD
(1) Install exhaust manifold and gasket. Tighten
bolts starting at the center working outward to 23
N·m (200 in. lbs.).
(2) Raise vehicle on hoist.
(3) Install front catalytic converter and manifold
heat shield. Tighten fasteners to 28 N·m (250 in. lbs.)
(Refer to 11 - EXHAUST SYSTEM/CATALYTIC
CONVERTER - INSTALLATION).
(4) Install exhaust cross-under pipe. Tighten fas-
teners to 28 N·m (250 in. lbs.) (Refer to 11 -
EXHAUST SYSTEM/CROSS-OVER PIPE - INSTAL-
LATION).
(5) Lower vehicle.
(6) Install oxygen sensor and connect electrical
connector.
(7) Connect negative battery cable.
REAR EXHAUST MANIFOLD
(1) Install exhaust manifold and gasket. Tighten
bolts working from center outwards to 23 N·m (200
in. lbs.).
(2) Install rear catalytic converter and manifold
heat shield. Tighten fasteners to 28 N·m (250 in. lbs.)
(Refer to 11 - EXHAUST SYSTEM/CATALYTIC
CONVERTER - INSTALLATION).
(3) Install oxygen sensor and connect electrical
connector.
(4) Install exhaust cross-under pipe. Tighten fas-
teners to 28 N·m (250 in. lbs.) (Refer to 11 -
EXHAUST SYSTEM/CROSS-OVER PIPE - INSTAL-
LATION).
(5) Install exhaust system. Tighten fasteners to 28
N·m (250 in. lbs.) (Refer to 11 - EXHAUST SYSTEM
- INSTALLATION).
(6) Lower vehicle.
(7) Install EGR tube using new gaskets. Tighten
screws to 11 N·m (95 in. lbs.).
(8) Install throttle body air inlet hose and air
cleaner housing assembly.
(9) Connect negative battery cable.
VALVE TIMING
DESCRIPTION
The timing drive system has been designed to pro-
vide quiet performance and reliability to support a
NON free-wheeling engine. The system consists of a
primary and secondary chain drive.
The primary timing chain drive (Fig. 108) uses a
single, double-flexure, inverted tooth type chain. The
primary chain drives both of the intake camshafts
directly from a sprocket mounted on the crankshaft.
In addition, the water pump is driven by the "back
side" of the primary chain, necessitating the double-
flexure type chain.
The chain is controlled by three fixed chain guides
and a pivoting tensioner arm (Fig. 108). These guides
utilize low-friction and long wearing nylon plastic
wear faces. To tension the primary chain, a fully
automatic spring-loaded, engine oil-fed, hydraulic
tensioner is used. The tensioner is mounted in the
right cylinder head with the plunger contacting the
pivoting tensioner arm. A mechanical ratchet mecha-
nism inside the tensioner prevents excessive chain
slack upon engine start-up as the chain wears. The
tensioner is designed with an internal oil reservoir to
assure noise-free performance, even during engine
start-up before oil pressure reaches the tensioner.
For lubrication the primary chain utilizes oil leak-
age from the front of the oil pump. This oil spills on
the crankshaft sprocket, which is then carried by the
chain throughout the primary drive.
JR
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