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Page 88
MAINTENANCE
BELT DRIVE SYSTEM
TENSIONING
[216]
The belt drive system uses a single, 10-rib poly-v
belt to drive the alternator, water pump, and fan
drive. A separate single-v belt, running off the
water pump pulley, drives the refrigerant
compressor. The service life of the poly-v belt is
considerably improved over other systems and
allows the use of higher horsepower cooling fans.
Refer to Figure 68.
Both manually tensioned and automatically
tensioned systems are used. Whether an engine
has the manually tensioned or automatically
tensioned system depends on the specific engine
configuration and application. The following
service information covers both systems.
68
Figure 68 — Belt Drive
Manually Tensioned System
INSTALLATION
Loosen the alternator mounting bolts and pivot
the alternator inboard, far enough to allow the
belt to be placed over the pulleys without force.
Do not pry the belt over a pulley.
TENSIONING
Using a belt tension gauge, such as J 41251-B
from Kent-Moore, check the belt tension at the
widest span between pulleys. Adjust belt tension
according to the following specifications:
r
New belt: 270 lbs.
±
10 lbs.
r
Used belt: 230 lbs.
±
10 lbs.
r
Minimum allowable tension (before
retension is required): 150 lbs.
MAINTENANCE
The belt tension and condition of the belt should
be checked when performing preventive
maintenance inspections A, B, C and D as
outlined in the
Maintenance and Lubrication
manual, TS494. Belts should be tightened when
needed, using the procedures described in this
manual.
Automatically Tensioned System
INSTALLATION
Swing the tensioner to the fully sprung position
and, without force, place the belt over the pulleys.
Do not allow the tensioner to snap against its
stops. Do not pry the belt over a pulley.
TENSIONING
No tensioning adjustment is required. Once the
tensioner is released against the belt, the belt is
tightened to optimum tension automatically at all
speeds and loads.
MAINTENANCE
The condition of the belt and tensioner should be
checked when performing preventive
maintenance inspections A, B, C and D as
outlined in the
Maintenance and Lubrication
manual, TS494. Belt tension level need not be
checked as long as tensioner is in good condition
and there is no evidence of a loose belt.
1. A/C Compressor
2. Water Pump
3. Alternator
4. Poly-V Belt
5. Tensioning Device
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