TM-9-2815-200-35 Maintenance Manual for AVDS-1790-2M AVDS-1790-2A and AVDS-1790-2AM Engines Download
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d. Forged steel valve rocker arms (A and B ) with roller cam-followers are used. The rollers are hardened and honed to provide an extremely smooth and permanent contact surface. Hollow rocker arm shafts and drilled passages in the rocker arms convey 1-16. Camshafts Note. The key parentheses refer to oil to all moving parts. letters shown below in figure 1-8. a. The left and right camshaft assemblies (C and K) are mounted, one on each bank, on the cylinders and operate the valve mechanism. The camshafts are hollow to provide oil passages for pressure lubrication to the valve parts and to permit deflection when the cylinders fire, Tubular molded rubber hoses enclose the camshafts between cylinders. b. Each camshaft is driven by the accessory drive gear (M), accessory drive gearshaft assembly (H), camshaft drive bevel gearshaft (G), camshaft drive gearshaft (E), and camshaft driven gear (D) through an inclined quill type camshaft drive shaft (F). The drive shafts can be rem oved to permit separate rotation of the camshafts for engine timing. When camshafts are correctly’ positioned in relation to the crankshaft, the drive shafts have different number of splines on each end and this allows them to be inserted in the camshaft bevel gearshafts without disturbing relationship between camshafts and crankshaft. 1-17. Lubrication System (figs. 1-9 and 1- 10) a. General. The main pressure oil pump draws oil from the pressure oil pump compartment in the oil pan. This compartment is fed by the scavenge oil pump which picks up oil from both ends of the engine oil pan. The pressurized oil is forced through the engine oil coolers and main oil filter to the engine oil galleries and bearings. A pressure regulator valve, located on the right side of the crankshaft damper and oil filter housing, is influenced by the pressure in the main bearing oil gallery and returns the in- coming excess unfiltered oil to the oil pan. A small portion of the pressure oil is diverted, after passing through the main oil filter, and passes through the auxiliary oil filter to provide the turbosuperchargers and the fuel injection pump with oil having a greater degree of filtration. The piston cooling oil pump picks up oil from the end compartment (rear) of the oil pan and delivers it to the piston oil sprayer nozzles. These nozzles are located in the crankcase, below each cylinder, and provide a continuous oil spray to the pistons and cylinder walls. b. Oil Pan. The oil pan (figs. 1-1 and 1-4) is a one-piece, aluminum alloy casting divided into a pressure oil pump compartment, oil reserve compartment, and the end compartments at the front and rear of the pan. The oil pan is designed to maintain a constant oil level above the main pressure oil pump pickup tube in the pressure oil pump compartment during vehicle operation regardless of the angle at which the engine may be inclined. 1-7