1988/02/01 Caterpillar

3508 Industrial, Marine And Generator Set Engines

Description of Change: A new crankshaft assembly is available for parts service for 3508 Industrial, Marine and Generator Set Engines. The new crankshaft assembly has improved mounting of the counterweights on the crankshaft. The mounting improvements include:

... The rear counterweight mounting surface has a very slight concave surface to increase loading of the two outer counterweight bolts.

... Hardened washers are installed in all counterweight counterbores to prevent galling (wear) between the under side of the mounting bolt heads and the counterweights.

... A new bolt tightening procedure increases the clamping load at the crankshaft to counterweight surface on counterweights. See "Counterweight Bolt Tightening Procedure" below.

Adaptable As: The new 9Y3798 Crankshaft Assembly is a direct replacement for the 7W210 Crankshaft Assembly in 3508 Industrial, Marine and Generator Set Engines.

Counterweight Bolt Tightening Procedure

1. Before assembly, put 2P2506 Thread Lubricant on the bolt threads, shank, washer, and bolt seat.

2. For the front and rear counterweights only, tighten all the bolts evenly to 200 ± 5 N·m (150 ± 4 lb ft). Loosen all the bolts.

3. Working across each counterweight-to-crankshaft joint, tighten all the bolts evenly to 70 ± 5 N·m (50 ± 4 lb ft).

4. Working across each counterweight-to-crankshaft joint, tighten each bolt an additional 120° ± 5°.