COVER-SIDE 7W3871 - Caterpillar

Cylinder Block Assembly
The cylinder block is of a skirted design that is made from cast iron. Drilled passageways allow oil to supply the oil for the crankshaft bearings and the pistons. Cooling passages are cast into the block. This engine utilizes wet cylinder liners that are serviceable. The configuration provides improved rigidity.The cylinder liner is a compacted graphite liner that is induction hardened. A steel spacer plate provides improved reusability and durability.Cylinder Head Assembly
The cylinder head is a one-piece cast iron head. The camshaft is contained within the cylinder head. This improves the rigidity of the valve train. Steel reinforced aluminum bearings are pressed into each journal. The bearings are lubricated under pressure. Bridge dowels have been eliminated as the valve train uses floating valve bridges.Thermal efficiency is enhanced by the use of stainless steel thermal sleeves in each exhaust port. The sleeves reduce the amount of heat rejection to the cooling system. The sleeves then transfer the thermal energy to the turbocharger.The electronic unit injector is mounted in a stainless steel sleeve. This sleeve has been pressed into the cylinder head injector bore. Pistons, Rings And Connecting Rods
The piston is a one-piece design that is forged steel. An oil cooling chamber is formed by the lip that is cast at the top of the piston and the cavity that is behind the ring grooves. The oil flow then returns to the sump through the clearance gap between the crown and the skirt. The pistons have three rings that are located in grooves in the steel crown. The rings seal the combustion gas and the rings provide control of the oil. The top ring has a barrel face. This ring is a KEYSTONE ring with a nitrided coating. The second ring has a square face with a nitrided coating. The third ring is the oil ring. The ring is double railed and the ring is profile ground. This ring is coated with nitride. The oil ring has a coil spring expander. There are four holes that are drilled from the piston oil ring groove to the interior of the piston. These holes drain excess oil from the oil ring.The cap of the connecting rod is attached to the shank by four bolts that are threaded into the shank. Each side of the small end of the connecting rod is machined at an angle of 12 degrees in order to fit within the piston cavity.Crankshaft
The crankshaft converts the combustion force in the cylinder into rotating torque. The rotating torque powers the equipment. On this engine, a vibration damper is used at the front of the crankshaft in order to reduce the torsional vibrations. The torsional vibrations can cause damage to the engine.The crankshaft drives a group of gears (front gear train) on the front of the engine. The front gear train provides power for the following components: camshaft, water pump, oil pump, sea water pump and transfer pump.The crankcase has seven main bearings that support the crankshaft. The crankcase