GEAR & BEARING GP-SWING 1994558 - Caterpillar

The gear train is located on the flywheel side of the engine.The crankshaft is the hub around which other parts of the engine can be timed and driven. This is done by the meshing of gears as shown in the Illustration 8.The timing gears transmit torque from the crankshaft to the oil pump and injection pump and, at the same time, correctly control fuel injection to the cylinders and valve timing.Each gear has an inscribed mating mark for correct and easy assembly and is spherical with teeth set obliquely to the axis of rotation to rotate smoothly and reduce noise.Flywheel
Illustration 9 g03007836
(20) Crankshaft
(21) Flywheel ring gear
(22) Flywheel The flywheel is made of heavy cast iron or steel, and has gear teeth around the outer rim of the flywheel, which mesh with the drive pinion of starter.The flywheel mounted on the rear of the crankshaft is a stabilizer for the whole engine.The flywheel stores the rotating force in the combustion stroke as inertial energy, reduces crankshaft rotating speed fluctuation and maintains the smooth rotating conditions.The flywheel periphery is inscribed with the marks showing fuel injection timing angle lines and top dead center mark TC.Rocker Arm
Illustration 10 g03009017
(23) Rocker arm shaft
(24) Rocker arm
(25) Exhaust valve
(26) Intake valve
(27) Bridge arm
(28) Push rod
(29) Adjusting screw The rocker arms are mounted on a rocker arm shaft at the top of the engine.When the push rods move up, the mating rocker arm is moved down, contacting the valve stem tip and opening the valve.These engines, two intake and two exhaust valves per cylinder, the rocker arm contacts a bridge arm instead of the valve stem tip. The bridge arm then contacts both intake or both exhaust valves and causes two valves to open simultaneously.Pressurized oil flows through the rocker arm shaft. Passages are drilled into the rocker arm shaft, which allows oil to flow into the annulus of the rocker arm bushing.Piston
Illustration 11 g03009120
(30) Concave head piston The reciprocating motion of a piston in the engine cylinder creates the forces for the suction, compression, power, and exhaust cycles.To be strong yet light, pistons are constructed of cast iron or aluminum alloys. Reinforcing ribs are used to keep the piston as light as possible.The piston lands are the areas between the ring grooves which hold and support the piston rings in the grooves. A fine groove called a heat dam is provided on the top land to protect the top ring from high temperatures.The skirt of the piston is the outside part below the ring grooves. The piston is kept in alignment by the skirt.The piston is kept in alignment by the skirt. The piston skirt has a layer of molybdenum disulfide, which decreases the piston slap noise.The molybdenum disulfide is a solid lubricant, like Graphite or Teflon. This material helps not to wear the metal even with little lube oil.Piston Rings
Illustration 12 g03009141
(31) Top compression ring
(32) Second compression ring
(33) Oil control piston ring Piston rings are classified as compression and oil control rings. Diesel engines have two or