Fuel systems on the 3208 Engines use four types of torque control groups; the stop bar, the torque spring (leaf), the fuel temperature compensator, and the Low Emission System (LES).
Governor and fuel injection pump groups with rigid torque control stops limit the performance of the engine to its natural torque rise. Fuel injection pump and governor groups with torque springs allow the engine to perform above its natural torque rise.
Torque control groups used in earlier fuel systems are fastened to the governor housing with two bolts. Later torque control groups, are fastened with a bolt and a stud. Use only the later method to fasten the torque control group to the governor housing when rebuilding a fuel system. The temperature compensating torque control group uses shorter bolts with special heads.
Stop Bar Torque Spring Group
(1) Adjustable stop.
The stop bar torque control is the most common. It uses a threaded adjustable stop (1) to adjust the fuel setting.
Torque Spring Control Group
(1) Shims. (2) Stop bar. (3) Leaf spring.
The torque spring control group uses a leaf spring (3) and a rigid stop bar (2) that is adjusted by inserting shims (1), of approriate thickness, between the stop bar (2) and the leaf spring (3), and lower insulator.
Fuel Temperature Compensated Torque Control Group
(1) Bellows. (2) Spring. (3) Rocker arm. (4) Fuel setting screw.
The fuel temperature compensator torque control group is used in mobile agricultural engine arrangements where the fuel temperature can get very hot. When the temperature of the fuel increases, the performance of the engine decreases. The fuel temperature compensating torque conntrol group increases the fuel setting when the fuel temperature increases to help keep engine performance normal. The space under the cover for the torque control group is completely filled with fuel when the engine is in operation. Bellows (1) senses (feels) the temperature of the fuel.
As the temperature of the fuel increases, the bellows expands (gets longer) and pushes down on the end of rocker arm (3). This will cause the opposite end of the rocker arm to move up against the force of spring (2). This will also move fuel setting screw (4) up and increase the fuel setting. The increase in the fuel setting will keep engine performance the same when the fuel temperature increases.
When the temperature of the fuel decreases to the normal fuel temperature, the bellows contracts (gets shorter) and spring (2) pushes down on rocker arm (3) and fuel setting screw (4). The fuel setting will return to the normal fuel setting.
Low Emission System (LES)/Exhaust Gas Recirculation (EGR) Switch Torque Control Group
(1) Load stop pin.
The Low Emission System (LES) torque control group uses a threaded adjustable stop and a series of electrical switches to control solenoids that position the Exhaust Gas Recirculation (EGR) valve. The standard load stop pin is replace with a load stop pin (1) with an extended arm. As the load stop pin (1) moves towards full load point, the arm actuates the switches.