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1D-2 Engine Mechanical:
Connecting Rods and Pistons
The connecting rods are sinterforged steel and have full
floating piston pins. The piston pins are a slip fit in the
bronze bushed connecting rod. Round wire retainers are
used to retain the piston pin into the piston. The cast
aluminum pistons incorporate a polymer-coated skirt to
reduce friction. The piston uses two low tension
compression rings and one multi-piece oil control ring.
The top compression ring is plasma sprayed. The
second compression ring is cast iron napier. The oil
control ring incorporates a steel expander and two
chrome plated steel rails.
Camshaft Drive System
The camshaft drive system consists of one primary
timing drive chain driven by the crankshaft sprocket. The
primary timing drive chain drives two intermediate drive
shaft sprockets. Each oil pressure fed intermediate drive
shaft sprocket drives separate secondary timing drive
chains. Each secondary timing drive chain drives the
respective cylinder head's intake and exhaust camshaft
position actuators.
The primary timing drive chain uses two stationary timing
drive chain guides and an oil pressure hydraulically
actuated tensioner with built-in shoe. The tensioner
minimizes timing drive chain noise and provides
accurate valve action by keeping slack out of the timing
drive chains and continuously adjusting for timing drive
chain wear. The tensioner incorporates a plunger that
adjusts out with wear allowing only a minimal amount of
backlash. The tensioner is equipped with an oiling jet to
spray oil onto the timing components during engine
operation. The secondary timing drive chains use a
stationary timing drive chain guide and movable timing
drive chain shoe. The secondary timing drive chain shoe
is under tension from an oil pressure hydraulically
actuated tensioner. All tensioners are sealed to the head
or block using a rubber coated steel gasket. The gasket
traps an adequate oil reserve to ensure quiet start-up.
From the initial production of the High Feature V6 there
have been four timing drive systems. This application
may have been built using the third or fourth design.
The third design uses an inverted tooth (IT) timing drive
chain on the primary timing drive components and roller
timing drive components on the secondary components.
NOTE: The difference between the third design and the
previous second design is a revised reluctor wheel on
the camshaft position actuators. The reluctor wheels
were revised due to revised camshaft position sensors.
The third design primary timing drive chain uses an IT
timing drive chain and a crankshaft sprocket with IT
timing drive chain teeth. The primary timing drive chain
connects the crankshaft sprocket with the left and right
side intermediate drive shaft sprockets. The third design
intermediate drive shaft sprockets incorporate IT primary
timing drive chain sprocket teeth and roller timing drive
chain secondary timing drive chain sprocket teeth. The
third design actuators incorporate a new reluctor wheel
and cannot be used on earlier designs.
The fourth design uses IT timing drive components on
both the primary and secondary components. NOTE:
The pitch of the IT chain has changed therefore third and
fourth primary IT components are not interchangeable.
The two timing drive system's individual rotating
components cannot be mixed. DO NOT mix third design
timing drive chain rotating components with fourth
design timing drive chain rotating components.
The following components are the ONLY components
that are same between the third and fourth design:
• All timing drive tensioners
• Primary Guides
• Secondary Shoes - Pivoting guides
Camshaft Position Actuator System
The engine incorporates a camshaft position actuator for
each intake and exhaust camshaft. Camshaft phasing
changes the inlet and exhaust valve timing within a
range of 25 camshaft degrees as engine operating
conditions vary. Dual camshaft phasing allows the
further optimization of performance, fuel economy and
emissions without compromising overall engine
response and driveability. Variable valve timing also
contributes to a reduction in exhaust emissions. It
optimizes exhaust and inlet valve overlap and eliminates
the need for an exhaust gas recirculation (EGR) system.
The camshaft position actuator is a hydraulic vane-type
actuator that changes the camshaft lobe timing relative
to the camshaft drive sprocket. Engine oil is directed by
a camshaft position actuator oil control valve to the
appropriate passages in the camshaft position actuator.
Oil acting on the vane in the camshaft position actuator,
rotates the camshaft relative to the sprocket. At idle, both
camshafts are at the default or "home" position. At this
position, the exhaust camshaft is fully advanced and the
intake is fully retarded to minimize valve overlap for
smooth idle. An internal lock pin locks the inner rotor to
the outer camshaft position actuator housing at idle and
maintains this position during start-up conditions. Under
other engine operating conditions, the camshaft position
actuator is controlled by the Engine Control Module
(ECM) to deliver optimal intake and exhaust valve timing
for performance, driveability and fuel economy. The
camshaft position actuator incorporates an integral
trigger wheel, which is sensed by the camshaft position
sensor mounted in the front cover to accurately
determine the position of each camshaft. Each camshaft
position actuator has a specific timing drive mark for
right or left bank application, as the camshaft position
actuators are common bank to bank. The exhaust
camshaft position actuator has a different internal
configuration than the intake camshaft position actuator
since the exhaust camshaft position actuator phases in
the opposite direction relative to the inlet camshaft
position actuator.
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Troubleshooting
