HEAD GP-CYL -UTN 20R1015 - Caterpillar

Pistons And Rings
The cast aluminum piston has two rings; one compression ring and one oil ring. The rings are located above the piston pin bore. The compression ring is a standard (conventional) type.The oil ring is a standard (conventional) type and is spring loaded. Holes in the oil ring groove provide for the return of oil to the crankcase.The direct injection piston has a special shape (cardioid design) of the top surface to help combustion efficiency. This piston also has a tapered pin bearing design. This provides a larger surface area at the top of the pin bearing to take the load of the power stroke more evenly.The prechamber piston has a steel heat plug assembled in the pocket (crater) on top of the piston. This plug protects the top of the piston from erosion (distortion by heat).The piston pin is retained by two snap rings which fit in grooves in the pin bore.Connecting Rods
The DI connecting rod eye end has the tapered design with the larger bearing surface at the bottom of the eye. This provides more surface area for the increased load of the power stroke.The PC connecting rod eye has the standard (conventional) type bearing.Electrical System
The electrical system has three separate circuits: the charging circuit, the starting circuit and the lighting circuit. Some of the electrical system components are used in more than one circuit. The battery (batteries), disconnect switch, circuit breaker, ammeter, cables and wires from the battery are all common in each of the circuits.
The disconnect switch, if so equipped, must be in the ON position to let the electrical system function. There will be damage to some of the charging circuit components if the engine is running with the disconnect switch in the OFF position.
The charging circuit is in operation when the engine is running. An alternator makes electricity for the charging circuit. A voltage regulator in the circuit controls the electrical output to keep the battery at full charge.If the machine has a disconnect switch, the starting circuit can operate only after the disconnect switch is put in the ON position.The starting circuit is in operation only when the start switch is activated.The starting circuit of a "PC" engine can have a glow plug for each cylinder. Glow plugs are small heating units in the precombustion chambers. Glow plugs make ignition of the fuel easier when the engine is started in cold temperature.The low amperage circuit and the charging circuit are both connected through the ammeter. The starting circuit is not connected through the ammeter.Charging System Components
Alternator
The alternator is driven by a V-type belt from the crankshaft pulley. It is a 12 volt, 40 ampere unit with a regulator which has no moving parts (solid state). The only part in the alternator which has movement is rotor assembly (9). Rotor assembly (9) is held in position by a ball bearing at each end of rotor shaft (8).The alternator is made up of a frame (3) on the drive end, rotor assembly