NMWR-9-2815-220 Overhaul Manual for M60 M88 Engine AVDS-1790-2CA, AVDS-1790-2DA, AVDS-1790-2DR Download
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NMWR 9-2815-220 EQUIPMENT DESCRIPTION AND DATA—Continued 0002 00 LOCATION AND DESCRIPTION OF MAJOR COMPONENTS - CONTINUED g. Camshafts. The key numbers in parentheses below refer to Figure 1 unless otherwise indicated. (1) Camshaft Assemblies. The left and right camshaft assemblies (3 and 10) are mounted, one on each bank, on the cylinders and operate the valve mechanism. The camshaft assemblies 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. (2) Camshaft Drive. Each camshaft is driven by the accessory drive gear (12), accessory drive gearshaft assembly (8), camshaft drive bevel gearshaft (7), camshaft drive gearshaft (5), and camshaft driven gear (4) through an inclined quill type camshaft drive shaft (6). The drive shafts can be removed 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. h. Lubrication System. Figure 2 is a flow diagram showing operational details of the lubrication system. (1) 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 the front end of the oil pan and by oil which drains into the pressure compartment from the cover of the pressure pump com- partment and the reserve compartment. The pressurized oil is forced through the engine oil coolers and oil filter to the engine oil galleries, bearings, turbosuperchargers, fuel injection pump, and 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. 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 incoming excess unfiltered oil to the oil pan. (2) Oil Pan. The oil pan is a one-piece aluminum alloy casting divided into a pressure oil pump compartment, oil reserve compartment, and the sump compartment at the front of the pan. Cored passages from each of the compartments terminate at a central outlet and permit draining all of the compartments from a single drainage point. A cored passage also permits draining the oil coolers and oil filter compartment directly without permitting any sludge to enter the oil 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. (3) Oil Pump. The oil pump assembly consists of four sections combined into a single unit. The scavenge oil pump section of the unit picks up oil from the front end compartment of the oil pan and delivers it to the main pressure pump oil compartment. The main pressure oil pump section picks up oil from its respective compartment and supplies oil to the engine oil galleries, bearings, and to the piston oil sprayer nozzles. The level in the pressure pump compartment is maintained by a dual inlet leveling pump which returns any excess oil to the reserve compartment. Oil is pumped from the reserve compartment by two make up pumps in a single pump section. These pumps pick up oil from opposite corners of the reserve compartment and discharge it into the pressure pump compartment. The dual pump design insures return of oil from the reserve compartment under all operating conditions, cold oil, slope operation, etc. (4) Oil Filters and Control Valves. The engine oil filters and the bypass valve are located in the crankshaft damper and oil filter housing at the front of the engine. All engine oil passes through the oil filters. The oil filter bypass valve opens at a differential pressure of 35.6 psi. The bypass valve permits oil to bypass the filters in the event that they become clogged. 0002 00-6 Change 1