TM-9-2815-200-35 Maintenance Manual for AVDS-1790-2M AVDS-1790-2A and AVDS-1790-2AM Engines Download
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(e) Double lip oil seal in cooling fan drive for deep-water fording to prevent water from entering the engine. (f) An improved fuel injection pump incorporating a filter at the fuel inlet to prevent foreign materials from entering the pump, thereby extending pump life. (g) Simplified and improved cooling fan clutch, eliminating the hydraulic engagement feature. (h) Oil filler tube has been relocated at left rear of left turbosupercharger to prevent oil spillage from plugging cylinder cooling fins and restricting air flow through the engine and transmission oil coolers. The relocation eliminated the need for the oil filler and indicator tube splash pan drain. (i) Primary fuel filter screen type element has been replaced with a high capacity replaceable-type element. (j) Wall thickness of cylinders has been increased to improve service life. Cylinders with increased wall thickness can be identified by machine groove around mounting base flange. (k) Drain cocks and hoses on fuel filters were replaced with rigid lines and drain valves located on top of the engine. (l) Additional clamps and supports have been added to fuel injection lines to reduce line breakage from vibration. (m) Added numerous tube and hose clamps and rerouted lines to prevent line failures from chaffing and vibration. (n) Added a preformed packing to starter drive bearing cage, and a flat gasket to the drive adapter to prevent oil leaks. Preformed packings cannot be used on engines which have bearing cages without the groove for the preformed packing. (o) Time totalizing meter added to record total engine operating hours. 1-7. Location of Engine Components a. In this manual the terms defined in b through e, below will be used to identify the location of parts and assemblies on the engines. b. The ends of the engines will be called the “damper end” or “front” and the “flywheel end” or “rear”. c. As viewed from the front end toward the rear, the side to the right will be called the “right side” and the side to the left will be called the “left side”. Beginning at the front, the right bank of cylinders is numbered lR through 6R and the left bank of cylinders is numbered IL through 6L. d. Starting from the front, the main bearings are numbered 1 through 7. e. The cylinders, pistons, connecting rods, and connecting rod bearings are numbered with their respective cylinder number locations. 1-8. General Description a. The Model AVDS-1790-2-M, AVDS-1790- 2-AM and the AVDS-1790-2A engines are 12- cylinder, 90 degree, V-type, 4-cycle, air-cooled, turbosupercharged, diesel engines. The cylinder assemblies are individually replaceable units, with overhead valves and valve rocker assem- blies in the head. The cylinders are arranged in two banks of six cylinders each. Each bank of cylinders has an overhead camshaft arrangement to actuate the valves of each cylinder. b. The engines feature a fuel injection system and a turbosupercharged air induction system which obtains optimum engine performance. The fuel injection system has a fuel injection metering pump which supplies metered fuel to individual cylinders through fuel injector nozzles. The fuel supply pump assembly (figs. 1- 3 and 1-6) located at the front of the engine, draws fuel through the primary and secondary fuel systems from the vehicle fuel tanks and delivers it to the injection pump. A tur- bosupercharger assembly (figs. 1-1, 1-2, 1-4, and 1-5 ) is located on each side of the engine at the rear. The turbosuperchargers are exhaust-gas driven and increase the air flow pressure entering the air intake manifolds (figs. 1-1, 1-2, 1-4, and 1-5). c. The engines are equipped with a 28 volt, 300 amp, dc generator (figs. 1-1 and 1-4) and a 24 volt solenoid operated starter (figs. 1-2 and 1- 5). d. The engines are lubricated by a forced feed system. The system consists of three circuits; i.e., the scavenge circuit, the main or pressure oil circuit, and the piston cooling circuit. These circuits are operated independently by one oil pump which consists of three separate sections. e. The engines are equipped with two intake manifold heaters (figs. 1-1, 1-2, 1-4, and 1-5) which are installed in the air intake systems between the intake manifold elbows and the turbo superchargers. The heaters, when operated, preheat the air entering the cylinders to facilitate cold weather starting and cold weather idle operation. 1-3