ALTERNATOR GP-CHARGING 2721889 - Caterpillar

3500 Family Of EnginesDescription of Change: A single wide belt is now used to drive the alternator in place of the two former V-belts on the 3500 Family of Engines. This belt has several small V-shaped grooves that fit small grooves in the new wide pulleys. The new design prevents failures caused by the former two belts hitting each other when vibrating. This results in longer belt life than either the 9.5 mm (.38") or 12.7 mm (.50") V-belts. The former standard 7C0504 Alternator Mounting Group has been replaced by a new 7E4836 Alternator Mounting Group. On the 3508 (95Y), 3512 (49Y), and 3516 (27Z) Industrial Engines that are used to drive fire pumps, the former attachment 7W6824 Charging Alternator Group has been replaced by the new 7E4837 Charging Alternator Group. (These two attachment groups include the new belt, the mounting parts, and the alternator.)
Adaptable To: The new 7E4841 Belt can be installed in place of either set of the former V-belts in all applications by installing a new 7E4840 Pulley (drive) and a new 7E4839 Pulley (driven). Tighten the alternator pulley bolt to 110 10 N m (80 7 lb ft). Tighten the new belt tighter than the former belts. If a belt tension gauge is used, the initial tension of the new belt should be 800 22 N (180 5 lb), and the tension after running 30 minutes or more at rated speed should be 490 45 N (110 10 lb). This tension is about 50% more initially and 20% more at rated speed than the tension for the former belts.