Usage:
All Caterpillar Machines Powered by 3412 Engines
- SUPPLEMENT: OCTOBER 25, 1999
Service Magazine SEPD0488, Article 30, Page 30, September 13, 1999; "Wider Crankshaft Gear Used".
The last sentence of the first paragraph is incorrect. The sentence should read as follows: "The new gear also requires a new timing gear housing". The title of the table in this article is also incorrect. The title should read as follows: "Housing - Timing Gear Changes".
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Description of Change: A new crankshaft spur gear is available for the engines in the above machines. The new spur gear is 23.50 mm (.925 inch) wide and is 5.72 mm (.225 inch) wider than the former spur gear. The new gear provides for a longer service life. The new gear also requires a new flywheel housing.
Adaptable To: The new 151-2940 Crankshaft Gear replaces the former 114-0966 and 2W-3878 Crankshaft Gears. The new wider gear is effective with 3412 (73W18310) Machine Engines and 3412E (80M2868) Machine Engines. The new crankshaft gear requires a different timing gear housing to provide clearance with the wider gear. The following table gives the appropriate housing changes.
The timing gear housing dimension from the gasket mounting face to the rear of the crankshaft seal mounting flange increased from 25.5 mm (1.004 inch) to 29 mm (1.142 inch). The crankshaft seal flange is the 10 mm (.40 inch) wide flange that has a 206 mm (8.11 inch) outside diameter that contains the front crankshaft seal.
The former 114-0966 Crankshaft Gear is still serviced for applications where the new or reworked timing gear housing change is not desirable.
The 0R-9751 Crankshaft Assembly (with the wider gear) is available as a remanufactured upgrade to new crankshaft assembly. 0R-2812, 0R-1207, 0R-1229 Crankshaft Assemblies (with the narrow gear) are also available as a remanufactured product.