PLANETARY GP-TRANSMISSION 1961800 - Caterpillar

Cylinder Block And Head
The cylinder block has seven main bearings. The main bearing caps are fastened to the cylinder block with two bolts for each cap.Removal of the oil pan allows access to the crankshaft, the main bearing caps, the piston cooling jets, and the oil pump.The camshaft is supported by bearings that are pressed into the cylinder block. There are seven camshaft bearings.The cylinder head is separated from the cylinder block by a nonasbestos fiber gasket with a steel backing. Coolant flows out of the cylinder block through gasket openings and into the cylinder head. This gasket also seals the oil supply and drain passages between the cylinder block and the cylinder head.The air inlet ports are on the left side of the cylinder head, while the exhaust ports are on the right side. There are two inlet valves and two exhaust valves for each cylinder. Replaceable valve guides are pressed into the cylinder head. The electronically controlled fuel injector is located between the four valves. Fuel is injected directly into the cylinders at high pressure. A pushrod valve system controls the valves. Piston, Rings And Connecting Rods
One-piece aluminum pistons are used in most applications. Engines with higher cylinder pressures require one-piece steel pistons. Refer to the Parts Manual in order to obtain information about the type of pistons that are used in a specific engine.Aluminum and Steel One-Piece Pistons
The aluminum and steel pistons have an iron band for the compression ring. The iron band helps to reduce wear on the compression ring groove. The pistons have three rings:
Compression ring
Intermediate ring
Oil ringAll of the rings are located above the piston pin bore. The compression ring is a Keystone ring. Keystone rings have a tapered shape. The action of the ring in the piston groove that is tapered helps prevent seizure of the rings. Seizure of the rings is caused by deposits of carbon. The intermediate ring is rectangular with a sharp lower edge. The oil ring is a standard type of ring or a conventional type of ring. Oil returns to the crankcase through slots in the bottom of the groove.Oil from the piston cooling jets sprays the underside of the pistons. The spray lubricates the pistons and the spray cools the pistons. The spray also improves the piston life and the spray also improves the ring life. The aluminum pistons use a single jet. The steel pistons use two jets. Refer to the Specifications, "Piston Cooling Jet" for more information.The connecting rod has a taper on the pin bore end. This taper gives the connecting rod and the piston more strength. The additional strength is concentrated in the areas with the most load. Two bolts hold the connecting rod cap to the connecting rod. This design keeps the connecting rod width to a minimum, so that the connecting rod can be removed through the cylinder. The rod and the original cap must be kept together.Crankshaft
The crankshaft changes the combustion forces in the cylinder into usable rotating