BEARING 4V3742 - Caterpillar

3500 Family Of Locomotive EnginesDescription of Change: A new rotocoil assembly is used. The new rotocoil assembly can be used in conjunction with a new valve stem oil shield. This new oil shield is installed on the inlet and exhaust valves of 3508, 3512 and 3516 Locomotive Engines. The valve stem oil shield was added to the inlet and exhaust valves of locomotive engines because they are typically run at low idle for an unusually large percentage of their operating time. The oil shield will help prevent oil "slobbering" (oil in exhaust manifolds and/or oil running out of manifold joints) when the engine is run at low idle for extended periods of time. Caterpillar does not recommend installing the oil shield on 3500 Engines in other applications unless the engine runs most of the time at low idle and has an oil "slobbering" problem. Installing the oil shield on engines in other applications could result in excessive valve stem and/or valve seat wear due to reduced lubrication.
Location of new 4P2521 Rotocoil (1) and 4P2522 Oil Shield (2) on the inlet and exhaust valves of locomotive engine cylinder head groups.Adaptable To: The new 4P2521 Rotocoil is a direct replacement for the former 7N7964 Rotocoil in all applications other than locomotive engines. In 3500 Locomotive Engines, the new 4P2521 Rotocoil and 4P2522 Oil Shield are a direct replacement for the former 7N7964 Rotocoil. The new 4P2520 Rotocoil Assembly includes one 4P2521 Rotocoil Assembly and one 4P2522 Oil Shield.