
RENR9968-02 23
Systems Operation Section
Camshaft
The camshaft has three lobes at each cylinder.
These lobes allow the camshaft to operate the unit
injector, the exhaust valves, and the inlet valves. The
camshaft is supported in the cylinder head by seven
journals which are fit with bearings. The camshaft
gear contains integral roller dampers that counteract
the torsional vibrations that are generated by the
high fuel pressu re during fue l inject or op erat ion. The
design reduces gear train noise. The camshaft is
driven by an adjustable idler gear which is turned
by a fixed idler gear which is turned by a cluster
idler gear in the gear train. Each bearing journal is
lubricated from the oil man ifold in the cylin der hea d .
A thrust plate that is located at the front controls the
end play of the camshaft. Timing of the camshaft is
accomplis hed by aligning marks on the crank shaft
gear and idler gear, and camshaft gear with a mark
on the front timing plate.
Vibration Damper
The twisting of the camsha ft is called to rs ional
vibration. The torsional vibration is caused by the
regular power impacts along the length of the
crankshaft. The vibration damper is installed on the
front end of the crankshaft. This vibration damper
is used to reduce the torsional vibrations. This
eliminates any damage that could occur to the
crankshaft.
The rubber damper is made of an outer hub
connected to an inner hub by a rubber ring. The
rubber makes a fle xible co upling between the outer
hub and the inner hub.
The viscous damper consists of a casing that is
welded to the inner hub. The casing contains a
steel weigh t that is susp ended in a viscous silicone
lubricant. The silicone lubrican t acts as a fle x ib le
coupling between the weight and the inner hub.
i02770527
Electrical System
SMCS Code: 1400; 1550; 1900
Reference
Refer to the Schematic and the Troubleshooting,
“Electronic Troubleshooting” for additional information
on your engine.
Grounding Practices
Proper grounding for the electrical system is
necessary for proper engine performance and
reliability. Improper ground ing will result in unreliable
electrical circuit paths and in uncontrolled electrical
circuit pat hs.
Uncontrolled engine electrica l circuit paths can result
in damage to the main bearings, to the crankshaft
bearing journal surfaces, and to the aluminum
components.
Uncontrolled electrical circuit pa ths can cause
electrical noise which may degrade performance.
In order to ensure proper functioning of the electrical
system, an engine-to-frame ground strap w ith a
direct path to the battery must be used. This may
be provided by a ground for the starting motor, by a
frame to the ground for the starting motor, or by a
direct frame to engine ground. An engine-to-frame
ground strap must be run from the grounding stud of
the engine to the frame and to the negative battery
post.
Connect the battery negative post to the frame rail.
From the frame rail, connect the ground wire to one
of the following locations:
•
Cylinder head ground stud
•
Optional engine ground stud connection
The engine must be grounded to the frame rail.
Connect the battery negative post to one of the
following locations:
•
Cylinder head ground stud
•
Optional engine ground stud connection
The engine must have a ground wire to the battery.
Ground wires or ground straps should be combined
at the studs that are only for ground use.
All of the ground paths must be capable of carrying
any potential currents.
The engine alternator should be grounded to the
battery with a wire size that is capable of managing
the full charging current of the alternator.