Dismantling and reassembling cylinder head

Compress the valve springs and remove the pushrods followed by the rocker arm brackets with the rocker arms. Back off uniformly the cylinder nuts and then spin them off; take down the cylinder heads with care so as to avoid the damage of the gaskets. Fig. Cylinder head: 1 — cylinder head; 2 — rocker arm bracket; 3 — adjusting screw: 4 — rocker arm assembly; 5 — rocker arm fulcrum pin; 6, 20 — nut; 7 — stud; 8 — valve cover; 9 — valve cotter; 10 — valve spring retainer; 11 — safety ring; 12 — valve spring; 13, 21 — gasket; 14 — valve guide; 15 — exhaust valve; 16 — inlet valve; 17 — pin; 18 — turbulence chamber insert; 19 — heater plug; 22 — tube; I — order of cylinder head nuts tensioning Apply pressure to spring retainers 10 in succession so as to remove cotters 9, and then remove retainers 10, springs 12, rings 11, exhaust valve 15 and inlet valve 16. Drive out turbulence chamber insert 18 from the socket in the cylinder head, using a copper drift inserted through the injector well. Exercise care so as not to fracture the insert. Pull valve guides 14 only if they need to be replaced. Rectify leaky valves by grinding. The valves seats showing scratches, indentations or traces of scorching must be cut with a cutter and the valves with the same defects of their heads need drinding on a grinder. After that, these valves must be ground in their seats. Eliminate any possible curvature of valve stem end faces by grinding. Scrap the valves with fractured stems or excessive wear on the cotter grooves and also those where the cotters, when assembled, sink deeply into their grooves. Scrap the springs showing residual deformation and fractures. Check the rocker arms for excessive axial and longitudinal play on their fulcrum pins and scrap components showing wear. Scrap fractured cylinder heads, make sure the stud threading is intact and the stud nuts are lightened home.

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Dismantling and reassembling the diesel engine

Use standard shop practice and conventional or specialized tools which are in good repair for the dismantling and reassembling of file engine and its units. On taking the engine apart, thoroughly clean the components of carbon and signs of corrosion, degrease and wash them. The general procedure of dismantling the engine is as follows: Close the shutoff cocks in the water and fuel lines; drain the cooling and lubricating systems of water and oil, respectively. Disconnect all the lines from the engine (fuel, water, exhaust) and disconnect the wires of the electrical system. Take down the pipework followed by the radiator (or water cooler and expansion tank), exhaust manifold, generator, starter motor, fuel injection pump, fuel and oil filters, cylinder head covers, air cleaners with pipework, injectors, cover plates of holes in the block and breather body. Take down the cylinder heads and liming gear cover plate. Remove the big end bearing caps and withdraw the pistons integrally with the connecting rods. Take down the speed governor, remove its gears (this applies to the 5Д2, 5Д2-1, 5П2, 8П2 and 10П2 engines). Take down the flywheel and flywheel casing, using a special puller. Withdraw the camshaft. Camshaft 21 is withdrawn integrally with front end bearing 22 and liming gear 1 on removing tachometer drive 17 and spinning off nut 18 holding fast the rear end bearing; the rear bearing itself is left in the block integrally with housing 19. Remove the sump (this applies to the ДС8, ДС12, П21, П22, 4ч and 6ч engines) and withdraw the crankshaft. Fig. Connecting rod, 5Д2, 5Д2-1, 5112, 8П2 and 10П2 diesel engines: 1 — camshaft timing gear; 2 — ratchet wheel; 3 — key; 4 — tab washer; 5 — tappet; 6 — exhaust valve pushrod; 7 — compression release handle; 8 — compression release spindle; 9 — disc of compression release spindle; 10 — inlet valve pushrod; 11 - spring; 12 — housing; 13 — spindle; 14 — driven bevel gear; 15 — drive bevel gear; 16 — cover plate; 17 — tachometer drive; 18 — nut; 19 — bearing housing; 20 — arm; 21 — camshaft; 22 — ball bearing; 23 — spacer ring To reassemble the engine, proceed in the reverse order, exercising care that all the components are returned into their places. Scrap used cotter pins, lock wires and tab washers. In deciding which of the parts is fit for further service, use the Table of Assembling and Running Clearance as a guide. On...

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Maintenance of electrical equipment

During the period when the engine is in service care must be exercised so as to avoid the soiling of electrical equipment with oil, fuel, water and dirt. Check the generator and starter motor commutators as well as brushes for condition at regular intervals; check the brushes for the pressure exerted on the commutators and check the terminals for contact also regularly. The commutator surface should be clean, free of both scratches and traces of scorching. Blow off the commutators with compressed air so as to remove dust and dirt, give them a rub with a clean benzine-soaked cloth. Remove all the scratches and traces of scorching with the aid of glass paper. Make sure the brushes are free to move in the brush holders, being parallel to the commutator segments, are in contact with the commutator at any point within their working surface and are free of excessive wear. If brushes lack proper contact with the commutator, they must be bedded to same, using glass paper. Place a strip of glass paper on the commutator under the brush so that the abrasive side of the paper faces the brush and puli the strip in the direction of commutator rotation. New brushes all need bedding in the same way. On bedding the brushes and cleaning the commutator, blow off the dust with compressed air and apply the cover band. If there are signs that the charging of the storage battery is an abnormal one, check the generator regulator for operation and make relevant adjustments. Wash the heater plugs in benzine during each maintenance.

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Maintenance of connecting rod-crank mechanism

When the engine is in service proceed as follows: Check the crankpin bearing bolts for locking. Check the crankshaft for alignment with the shaft of the driven machine. Renew in good time those components which show wear (this particularly applies to bearings, piston rings, etc). Clean the pistons and piston rings of carbon.

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Maintenance and adjustment of valve gear

Maintain the valve clearances anywhere between 0.25 and 0.3 mm. remembering that a smaller clearance prevents the valves to seat leakproof when the engine is in operation whereas a wider one impairs the scavenging and filling of cylinders. Check and adjust the valve clearances on the cold engine, proceeding in accordance with the firing order, when the piston is set to t.d.c. on the compression stroke (the valve will be in the closed position). Use for clearance measurements a feeler gauge and set each clearance by screw 3. Remove cover 8 and check the brackets of rocker arm 2 and the cylinder head for loose nuts preparatory to proceeding with the valve clearance adjustment. On finishing this adjustment, lock screws 3 and crank over the engine so as to be sure that no valve strikes the piston crown, indicating that the clearances have been set correctly. Fig. Cylinder head: 1 — cylinder head; 2 — rocker arm bracket; 3 — adjusting screw: 4 — rocker arm assembly; 5 — rocker arm fulcrum pin; 6, 20 — nut; 7 — stud; 8 — valve cover; 9 — valve cotter; 10 — valve spring retainer; 11 — safety ring; 12 — valve spring; 13, 21 — gasket; 14 — valve guide; 15 — exhaust valve; 16 — inlet valve; 17 — pin; 18 — turbulence chamber insert; 19 — heater plug; 22 — tube; I — order of cylinder head nuts tensioning After a period in operation, valves may fail to seat tightly in their seats, and the leakproofness must be restored by grinding the leaky valves. Preparatory to grinding, remove the valves from the cylinder heads, clean them of carbon and wash. Place a spring under the valve head, apply to the valve face а ГОИ №20 grinding compound diluted in oil and begin to oscillate the valve hack and forth, giving it a quarter-turn al a lime, with the aid of a brace or valve grinder, and change the position of the valve step-wise, releasing the pressure between the oscillations so as to enable the spring to lift the valve from its seat. Never give rotary motion to the valve being ground since this is conductive to circumferential scratches on the faces. Add more of the compound from time to time and continue the grinding until polished lines of uniform width will run continuously around both the valve and its seat. Wash the...

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Maintenance of cooling and warming-up system

A point to be rioted is that the malfunctioning of the system impairs normal operation of the engine from the standpoint of its temperature. The defects which are likely to occur are as follows: Overheating of the engine due to pump breakdown, inadequate water or air delivery (on stationary engines poor water or air delivery may be attributed to a slack drive belt), clogged water jackets and lines, excessive formation of scale in the system, inadequate amount of coolant in the cooling system and malfunctioning of the thermostat. Overcooling of the engine due to inadequate thermal insulation applied to protect the engine from low ambient temperatures or a breakdown of the thermostat. Leaks from the system resulting from failure to tighten mounting hardware, to replace defective gaskets, to renew seals and leaks through fractures. The maintenance of the cooling system consists of eliminating all the above defects in good time. The tension of the pump and fan belts must be such that the belt has 10 to 15 mm of movement under a thumb pressure of roughly 3 kg applied at a point midway between the pulleys. The bell tension is restored to normal by turning the generator. Other items requiring attention so as to assure normal operation of the system are as follows: Fill the system with soft water, preferrably with rain water, added whereto is potassium bichromate, using a funnel with a strainer. If the water available is a hard one, soften it by boiling or add thereto sodium hydroxide taken in an amount of 40 g per 60 l of water. Top up the level of water when the engine is warm by adding the water gradually in small amounts without stopping the engine or otherwise the fracturing or warping of cylinder heads is likely to occur, especially if the engine is overheated. Flush the system with clean water at regular intervals. Avoid changing the water in the system without good reason thereto or otherwise intensive scale formation may occur. Rinse the water drained from the system. Descale the system if the scale exceeds 1 mm in thickness, using the following composition: phosphoric acid, H3PO4 (s.g.1,71) - 100 cm3 water - 90 cm3 chromic anhydride, CrO3 - 50 g In preparing the descaling composition, pour the measured amount of water into the phosphoric acid, add the chromic anhydride and stir the mixture thoroughly. Preparatory to filling the cooling system with the descaling composition prepared, disconnect the radiator or water cooler and remove...

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Maintenance of lubricating system

Proper functioning and good maintenance of the lubricating system are factors influencing the wear of components, power output and economy of the engine. The main defects impairing the normal functioning of the lubricating system are surplus or lack of oil in the system; blocked or damaged oil passages, oil lines, oil cooler (on the 6ч engine) or oil filter; low oil pressure; water in the lubricating system. Drain the sump, governor and fuel injection pump of oil when shutting down the engine for a protracted period at ambient temperatures under 8° C. Fill the sump, governor and fuel injection pump with warmed up oil preparatory to starting the engine after this shutdown. On the engines fitted with the heater, no draining of the oil from the sump and fuel injection pump is required. Clean and wash blocked oil passages and clogged filters. Repair or renew damaged oil lines and oil filters. For adjusting the pressure of oil, use the adjusting screw of the pressure-reducing valve, turning same down to increase the oil pressure and turning up when the pressure in the system must be reduced. If water has entered the system, drain same of oil, locate and eliminate the defect. To remove sediments from the lubricating system, flush it with a mixture of fuel oil (75%) and crankcase oil (25%) or with grade ВНИИНП-113 flushing oil every 600 running hours. The flushing oil of the grade recommended is also a detergent removing carbon from the piston and piston rings. The procedure of flushing the lubricating system is as follows: Drain the sump of oil while the engine is hot; wash the strainer, primary and secondary oil fillers as well as the oil cooler (applies to the 6ч diesel engine). Fill 1 the sump either with the mixture of fuel oil and crankcase oil prepared in advance or with the flushing oil so that the level is at the top mark on the oil level gauge, start the engine and give it an idle run lasting between 10 and 15 min. Stop the engine, drain the sump of the mixture or flushing oil and fill with fresh crankcase oil.

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