81781M Mariner NUT, INLET COVER SCREW

Illustration 1 g02191598
Lubrication system schematic (typical example)
(1) Main engine oil gallery
(2) Engine oil gallery for the left camshaft
(3) Engine oil gallery for the right camshaft
(4) Engine oil gallery for the piston cooling jets
(5) Piston cooling jet
(6) Engine oil supply for the turbochargers
(7) Sequence valve
(8) Sequence valve
(9) Adapter
(10) Engine oil filter base
(11) Engine oil cooler
(12) Bypass valve
(13) Relief valve
(14) Engine oil pump
(15) Elbow
(16) Suction bell
(17) Engine oil filter Engine oil pump (14) has three gears that are driven by the front gear train. The engine oil pump pulls engine oil from the pan through suction bell (16) and elbow (15). The suction bell has a screen in order to strain the engine oil.Relief valve (13) controls the maximum pressure of the engine oil from the engine oil pump. If the pressure from the pump becomes excessive, the relief valve opens and some of the engine oil returns to the engine oil pan.Engine oil cooler (11) reduces the temperature of the engine oil. The engine oil cooler has bypass valve (12) that is designed to open if the cooler becomes restricted.
Illustration 2 g00928818
(10) Engine oil filter base
(17) Engine oil filter housing Engine oil filter base (10) provides the mount for engine oil filters (17). The base has an internal bypass valve.The bypass valve will open if there is a restriction in the engine oil cooler or in the engine oil filter. The bypass allows the engine to be lubricated if the engine oil cooler is plugged or if the engine oil filter is dirty.Clean engine oil from the engine oil filters goes through adapter (9) into the block. Part of the engine oil goes to left camshaft oil gallery (2). The remainder of the engine oil goes to main engine oil gallery (1).Engine oil galleries (2) and (3) supply engine oil through drilled passages to the camshaft bearings. The engine oil circulates around each camshaft journal. The engine oil then flows through the cylinder head and through the rocker arm housing to the rocker arm shaft. Some of the engine oil lubricates the valve stems. The remainder of the engine oil drains from the cylinder head in order to lubricate the pushrods, the valve lifters, the camshaft, and the camshaft bearings.Engine oil from main engine oil gallery (1) is supplied to the main bearings through drilled passages. Drilled holes in the crankshaft supply engine oil from the main bearings to the connecting rod bearings. Engine oil from the rear of the main engine oil gallery goes to the rear of right camshaft oil gallery (3).Sequence valves (7) and (8) allow engine oil from main engine oil gallery (1) to enter engine oil galleries (4) for piston cooling jets (5). The sequence valves will not allow engine oil into gallery (4) for the piston cooling jets until there is pressure in the main engine oil gallery. This reduces the amount of time that is required for pressure buildup when the engine is started.
Illustration 3 g00928859
(5) Piston cooling jet Piston cooling jet (5) is located in the engine block below each piston. Each piston cooling jet has two tubes with open ends. One tube directs engine oil into an opening in the bottom of the piston for an engine oil gallery in the piston. This gallery provides cooling oil behind the ring band of the piston. The gallery provides engine oil to a slot (groove) in the side of both piston pin bores. The other tube directs engine oil to the center of the piston. This provides lubrication to the piston pin and to the piston undercrown. This also helps cool the piston.
Illustration 4 g00928860
Lines for engine oil
(6) Supply line
(18) Drain line Supply line (6) provides engine oil for lubrication of the turbocharger bearings. The engine oil flows through drain line (18) into the front housing.Engine oil is provided to the front and rear gear groups through drilled passages in the front housings, in the rear housings, and in the faces of the cylinder block. These passages are connected to engine oil galleries (2) and (3) for the camshafts.After the oil has completed lubrication, the engine oil returns to the engine oil pan.