Usage:
3176C (6BW),
3196 (2XR) MARINE ENGINES
Problem:
There have been some reports of early hour failures of the Turbocharger Mounting Studs on these engines. These studs are installed in the exhaust manifold flange, which is part of the raw water aftercooler group. The illustration shows the locations of the turbocharger mounting studs in a typical raw water aftercooler group. Section .02
Solution:
If a turbocharger mounting stud fails on one of these engines, replace all four studs with new 133-7810 Studs obtained from the Caterpillar parts system. DO NOT use 9X-8281 Studs. The 133-7810 Stud is much stronger in this application. Tighten the turbocharger mounting nuts to a torque of 55 N(m (41 lb ft). The 143-9730 Turbocharger Nut Wrench is available to help make the nuts more accessible when using a torque wrench.
In our investigation of this problem, we discovered that the production supplier of the aftercooler group used an alternate stud. This stud was from a different supplier than the supplier providing the 133-7810 Stud that is available in the parts distribution system. The alternate stud was softer and had a lower tensile strength than the requirements for the 133-7810 Stud. In addition, the turbocharger mounting nuts were over tightened during the assembly process.
A contributing factor to turbocharger mounting stud failure can be the forces exerted on the turbocharger/exhaust manifold joint by the exhaust connection. A well designed exhaust system will have two flexible joints with one flexible joint as close to the engine as possible. The system will have a support brace to support the weight of the exhaust. This support brace will be tied back to the transmission. The maximum allowable static vertical weight on the centerline of the customer exhaust connection for these engines is 24 lbs. The maximum allowable static offset force is 20 lb ft.
Location of Turbocharger Mounting Studs (1) In A Typical Raw Water Aftercooler Group
RIGHT SIDE VIEW
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