Engine d 245 12 removal of a cam-shaft gear. Trucks gas, zil, kamaz, urals, maz, kraz
The gas distribution mechanism consists of a camshaft, intake and exhaust valves, as well as parts of their installation and actuator: pushers, rods, rocker arms, adjusting screws with nuts, plates with crackers, springs, struts and the axis of the rocker arm.
Pushers - steel, have spherical bottoms. As a result of the fact that the cams of the camshaft are made with a slight slope, the pushers during the operation rotate.
Pusher rods are made of steel bar. The spherical part that enters the push rod and the rod cup are hardened.
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Rocker arms - steel, swing on an axis mounted on four racks. Extreme racks - increased rigidity. The axis of the rocker arm is hollow; It has eight radial holes for lubricating the rocker arm. The movement of the rocker arm along the axis is limited by spacer springs.
Inlet and outlet valves are made of heat resistant steel. They move in guide bushings pressed into the cylinder head. Each valve closes under the action of two springs, external and internal, which act on the valve through a plate and crackers.
Sealing cuffs installed on the valve guide bushings prevent oil from entering the diesel cylinders through the gaps between the valve stems and the guide bushings.
The working surfaces of the support necks and cams of the camshaft must be clean, without nicks and marks.
The camshaft cam height should be 41.32 ± 0.05 mm.
The surfaces of the cams must be machined to a cone (Fig. 2). The larger base of the cone should be on the side of the camshaft gear.
The diameters of the necks of the camshaft must be at least 49.88 mm (for a new shaft - 50-0.050 mm).
The non-circularity and the tolerance of the longitudinal section profile of each camshaft neck is 0.01 mm.
The oil channels of the camshaft must be clean, with no traces of tarry deposits. The channels must be thoroughly rinsed and purged with compressed air.
The gear should be pressed onto the camshaft until it stops. The bolt of the gear to the camshaft must be tightened to a torque of 110 ... 160 Nm.
The gap between the end of the neck of the assembled camshaft and the stop flange (axial play of the shaft) is allowed within 0.3 ... 1.04 mm (see Fig. 2).
The sleeve must be pressed into the intermediate gear flush with the ends. The surfaces of the ends of the gears and bushings must be clean, without dents. The roughness of the treated surfaces is Ra≤2.5 microns.
The inner surface of the intermediate gear bushing must be clean, free from scratches and nicks. The roughness of the treated surface is Ra≤2.5 microns.
The non-circularity and the tolerance of the longitudinal section profile of the inner surface of the intermediate gear sleeve are 0.008 mm.
The splined flange of the gear of the fuel pump drive should freely, without jamming, go into the splines of the pump roller sleeve.
The replaceable fuel pump drive gear bushing should be pressed in from the short hub side until the bushing stops at the end of the gear hub.
When adjusting the gap between the end face of the adjusting bolt and the surface of the plank, the adjusting bolt should be screwed into the plank all the way, then unscrew by ⅓ ... ½ turn and lock with a nut.
The D-245 diesel engine installed on the GAZ-3309, GAZ-3308, GAZ-33081 Sadko cars is a four-stroke, four-cylinder, vertical, in-line diesel engine with turbocharging the water-cooled air sucked into the cylinders with a starter start.
Head and cylinder block of diesel D-245
The cylinder block of the D-245 engine is the main body part of the diesel engine and is a hard cast iron casting. Four removable sleeves 5 made of special cast iron are installed in the vertical bores of the block.
Sleeves are installed in the cylinder block along two centering belts: upper and lower. In the upper zone, the sleeve is fixed and sealed with a collar, and in the lower one, by two rubber rings 6 installed in the grooves of the block.
Fig. 1. The cylinder block of the diesel engine GAZ-3309, GAZ-3308, GAZ-33081 Sadko
1- distribution cover; 2 gaskets; 3 - shield distribution; 4 cylinder block: 5 - liner; 6 - rings (8 pcs.); 7 - back sheet; 8 - cuff; 9 - cuff body: 10 - crankcase support; 11- covers of main bearings (5 pcs.)
The end walls and transverse partitions of the D-245 engine block in the lower part have tides designed to form the upper bearings of the crankshaft.
On these tides are installed covers 11, which serve as lower supports crankshaft. The tides together with the covers 11 form beds for the main bearings.
The beds for the main bearing shells are bored assembly with the main bearing caps, so you cannot change the covers in places.
The cylinder block has a longitudinal rope, from which oil flows through the transverse channels to the crankshaft main bearings and the camshaft bearings.
The cylinder block of the D-245 diesel engine in the second and fourth upper bearings of the crankshaft has nozzles that serve to cool the pistons with a jet of oil.
On the outer surfaces of the diesel engine block there are machined mating planes for fastening the centrifugal oil filter water pump, filters rough and fine cleaning fuel, oil filler neck and oil sump, which is bolted and sealed with rubber half rings and gaskets.
Cylinder liners are cast from a special alloy with high wear resistance. Sleeves - wet, removable.
In the upper part they have a shoulder, the protrusion of which above the surface of the block is 0.05 ... 0.11 mm. In the lower part of the sleeve are sealed with two o-rings. The inner surface of the sleeve has been specially honed.
Cylinder liners D-245 in internal diameter produce three size groups. The designation of the groups (B, C, M) is applied on the upper collar of the sleeve and on the piston bottom.
Fig. 2. The cylinder head of the engine GAZ-3309, GAZ-3308, GAZ-33081 Sadko
1 - head gasket; 2 - air inlet channel; 3 - guide bush; 4 - valve springs; 5 - valve plate; 5a - cracker; b - stud pin; 7- hole for the nozzle; 8 - inlet valve; 9 - exhaust valve; 10 - hole for the bar; 11 - rack; 12 - axis of the rocker arm; 13 - rocker: 14-nozzle
The cylinder head is made of special cast iron and has internal inlet and outlet channels closed by the corresponding valves 8, 9. The head has internal cavities in which coolant circulates to remove heat.
The cylinder head has plug-in valve seats made of heat-resistant and wear-resistant alloy.
From above, on the cylinder head, racks 11, an axis 12 with rocker arms 13, a head cover, an intake manifold and a cap cover covering the valve mechanism are installed.
Four nozzles 14 are installed in the head on the fuel pump side, and an exhaust manifold is attached to the head on the generator side.
To seal the connector between the head and the cylinder block, an asbestos-based gasket is installed, the openings of which for cylinder liners and the oil channel are edged with sheet steel.
Immediately prior to installation on a D-245 diesel engine, the cylinder bore holes are additionally edged with split fluoroplastic rings.
KShM of the D-245 engine (GAZ-3309, GAZ-3308, GAZ-33081 Sadko)
The main details of the crank mechanism are: crankshaft 2 with counterweights 3, pistons 4 with piston rings 5 \u200b\u200band fingers 6; connecting rods, main 9 and 12 connecting rod bearings; flywheel.
The engine crankshaft D-245 steel, has five main and four connecting rod journals, subjected to induction hardening to increase strength and wear resistance.
There are cavities in the connecting rod journals of the crankshaft for additional centrifugal oil cleaning. The cavities of the necks are closed with threaded plugs 10.
The axial force of the D-245 engine crankshaft is perceived by four half rings 13 mounted in the bores of the cylinder block and the cover of the 5th main bearing. Counterweights 3 are installed on the 1st, 4th, 5th and 8th cheeks of the crankshaft.
A gear 14 of the crankshaft, gear 15 of the drive of the oil pump and a pulley 1 of the drive of the water pump and generator are mounted on the front end of the crankshaft. A flywheel is mounted on the rear flange of the shaft.
Crankshafts can be manufactured and installed on a diesel engine in two production sizes (ratings) 1H and 2H.
The crankshaft with connecting rod and main necks 2H has an additional marking on the first cheek: 2K - main necks of the 2nd face value; 2Sh connecting rods of the 2nd nominal; 2KSh - connecting rod and root necks of the 2nd face value.
In order to extend the service life of the D-245 crankshaft when they are worn above the permissible limit, it is recommended to grind the necks to repair dimensions.
To obtain the desired clearance in the bearings, it is necessary to install repair liners corresponding to the repair dimensions of the necks.
The connecting rod is made of chrome steel, forged, I-section. A bimetal (steel-bronze) sleeve is pressed into the upper head of the connecting rod. To lubricate the piston pin, there is a hole in the upper connecting rod head and sleeve.
The lower connecting rod head has a horizontal connector with a cover. Boring a bed under steel-aluminum inserts is complete with a lid.
The connecting rod and engine cover GAZ-3309, GAZ-3308, GAZ-33081 Sadko have the same digital markings on the side ends for proper assembly.
In addition, at the end of the upper connecting rod head there is a weight group marking. Diesels should be equipped with connecting rods of the same weight group.
The piston is made of aluminum alloy. At the bottom of the piston there is a toroidal combustion chamber. In the upper part, the piston has four grooves for the piston rings.
The upper compression ring is chrome-plated and barrel-shaped. The upper compression ring of diesel engines is chrome-plated and has a trapezoidal shape. The ring is installed in the groove of a special insert made of wear-resistant cast iron in the piston body.
The piston pin of the engine D-245 floating type, hollow, made of chrome-nickel steel. The axial movement of the finger in the piston bosses is limited by two retaining rings.
The box-type oil scraper ring with the expander is marked “UP” on the end surface facing the piston crown. The ring has a chrome coating to increase wear resistance.
Pistons on the outer diameter of the skirt are classified into three size groups (B. S, M), which are marked on the piston bottom.
The gas distribution mechanism of the D-245 engine of the GAZ-3309, GAZ-3308, GAZ-33081 Sadko cars
The gas distribution mechanism (Fig. 3) has an overhead valve system. The inlet and outlet valves 14 are connected to the camshaft 1 through pushers 2, rods 3. adjusting screws 4 and rocker arms 7.
Pushers 2 have spherical bearing surfaces and in the process of operation make a rotational movement. Steel rods 3 have hardened spherical and cup-shaped parts.
Fig. 3. The timing mechanism D-245
1-camshaft: 2 - pusher; 3 - rod: 4 - adjusting screw; 5 - a lock-nut; 6 - axis of the rocker arm; 7 - rocker; 8 - crackers; 9- plate; 10- sealing cuff; 11-spring outer; 12-spring inner; 13 - rack; 14 - a directing sleeve; 15 - valve: 16 - extreme rack; 17 - spring axis rocker
Rockers 7 - steel, swing on the axis 6, mounted on four racks 13. Extreme racks 16 - high rigidity. The axis 6 is hollow, has eight radial drills to lubricate the rocker arms. The axial movement of the rocker arm is limited by springs 17.
Inlet and outlet valves D-245 of GAZ-3309, GAZ-3308, GAZ-33081 Gadgets Sadko are made of heat-resistant steel and move in guide bushings 14, pressed into the cylinder head.
Each valve closes under the action of two springs 11, 12, which act on it through a plate 9 and crackers 8. Sealing cuffs 10 mounted on the guide sleeves 14 prevent oil from entering the diesel cylinders through the gaps between the valve rods and the guide sleeves.
Fig. 4. Camshaft d-245
1 - cams of a camshaft; 2 - supporting necks: 3 restrictive plate; 4 - a camshaft gear;
The camshaft of the D-245 engine (Fig. 4) has three support journals 2 and is driven into rotation from the crankshaft through the distribution gear. The camshaft bearings are three bushings pressed into the bores of the cylinder block.
The front hub (on the fan side) of the aluminum alloy camshaft has a thrust collar that, using the plate 3, keeps the shaft from axial movement. Middle and rear bushings are cast iron. The restriction plate 3 is bolted 7 to the cylinder block.
Distribution gear 4 is mounted on the key and mounted on the shaft with bolt 6 and lock washer 5.
Fig. 5. Gears of distribution of the diesel engine D-245
1 - gear wheel drive oil pump steering; 2- camshaft gear; 3 - an intermediate gear; 4 - a gear wheel of a fuel pump drive; 5 - a gear wheel of a cranked shaft; 6 - gear drive oil pump lubrication system; K, P and T-tags on an intermediate gear
The distribution gears (Fig. 5) of the diesel engine are mounted in a cast-iron distribution cover bolted to the cylinder block.
Distribution gears 5, 3, 4 transmit torque from the crankshaft to the fuel pump and steering oil pump and control the fuel injection into the cylinders and the valve timing.
The gears have the marks K, P, T. When assembling, it is necessary to combine the marks K, P and T of the intermediate gear 3 with the corresponding marks on the gears 5, 2 and 4 of the crankshaft, camshaft and fuel pump shaft.
When the engine is operating in high-speed mode, the open time of the valves must be increased by their overlap in order to let in as much air as possible and remove as much exhaust gas from the cylinders as possible.
The inlet valves open until the end of the exhaust stroke and remain open after the start of the compression stroke. The exhaust valves open before the end of the compression stroke and remain open after the start of the suction stroke.
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Timing and D-245 diesel valves
Timing distribution mechanism D-245 of ZIL-5301 cars Bychok, GAZ-3309, MAZ-4370 The cog consists of a camshaft, intake and exhaust valves, as well as parts of their installation and drive: pushers, rods, rocker arms, adjusting screws with nuts, plates with crackers, springs, struts and rocker arms.
Camshaft - five-way, driven by the crankshaft through the gears of distribution. The camshaft bearings are five bushings pressed into the block bores.
The front hub (on the fan side) of aluminum alloy has a thrust collar that holds the D-245 camshaft from axial movement, the rest of the bushings are made of special cast iron.
Pushers of valves - steel. The working surface of the pusher plate is fused with bleached cast iron and has a spherical surface with a large radius (750 mm). As a result of the fact that the camshafts are made with a slight slope, the pushers during the operation make a rotational movement.
Pusher rods are made of steel bar. The spherical part that enters the push rod and the rod cup are hardened. Rocker arms - steel, swing on an axis mounted on four racks. Extreme racks - increased rigidity.
The axis of the rocker arm is hollow, has eight radial holes for supplying oil to the rocker arms. The movement of the rocker arm along the axis is limited by spacer springs.
D-245 intake and exhaust valves are made of heat-resistant steel. They move in guide bushings pressed into the cylinder head. Each valve closes under the action of two springs: external and internal, which act on the valve through a plate and crackers.
Sealing cuffs installed on the valve guide bushings prevent oil from entering the diesel cylinders and the exhaust manifold through the gaps between the valve stems and the guide bushings.
The coordinated operation of the high-pressure fuel pump and the gas distribution mechanism is ensured by the installation of distribution gears for the labels in accordance with Figure 1.
Fig. 1 - Installation diagram of the timing gears of the D-245 engine
1 - camshaft gear; 2 - an intermediate gear; 3 - a gear wheel of a cranked shaft; 4 - a gear wheel of a fuel pump drive.
Basic instructions for grinding in valves of diesel engines D-245
Turn away nuts of fastening of racks of an axis of a yoke and dismantle an axis of a yoke with springs and yokes. Turn away bolts of fastening of a head, remove a head. Dry the valve, remove the plate of the valve springs, valve springs, valve spring washers; Remove the sealing collar from the valve guide sleeve.
Grind valves on special machines or on stands. On valve chamfers or socket chamfers cylinder heads apply a paste prepared from a special composition. The composition is diluted in diesel oil to a creamy state. To improve the quality, it is recommended to add oleic or stearic fatty acid.
Lapping of the D-245 valves of ZIL-5301 automobiles Bychok, GAZ-3309, MAZ-4370 Continue the notch until a continuous matte band with a width of at least 1.5 mm, strip breaks or the presence of Risk not allowed. The difference in width of the belt is not more than 0.5 mm.
After lapping, flush the valves and the head of the engine block. When assembling the head, lubricate the valve stem with engine oil. It is possible to grind the valves manually using a bench tool, but the laboriousness of the grinding operation is significantly increased.
Checking the tightness of the bolts securing the cylinder head of the D-245 diesel engine
Check the tightening of the bolts for fastening the cylinder head D-245 at the end of the run-in and every 40 thousand kilometers on a heated diesel engine in the following order:
Remove the cap and cylinder head cover;
- Remove the axis of the rocker arm with rocker arms and struts;
- using a torque wrench, check the tightening of all the cylinder head bolts in the sequence shown in Figure 2, and, if necessary,
a lift. Tightening torque - 220 ± 10 Nm.
After checking the tightness of the cylinder head mounting bolts, reinstall the rocker arm axis and adjust the clearance between the valves and rocker arms.
Fig. 2 - Sequence diagram for tightening the cylinder head bolts
Checking the clearance between the valves and rocker arms of the D-245 engine
Check the gaps between the valves and rocker arms of the D-245 engine and, if necessary, adjust every 20 thousand kilometers, as well as after removing the cylinder head, tightening the bolts securing the cylinder head and when a valve knock appears.
The gap between the rocker arm and the end of the valve stem when checking on an unheated diesel engine (water and oil temperature no more than 60 ºС) should be:
Intake valves - 0.25 mm;
- exhaust valves - 0.45 mm.
When adjusting the gap between the end of the valve stem and the rocker arm on an unheated diesel engine, install:
inlet valves - 0.25 mm;
exhaust valves - 0.45 mm
The gap between the beam and the valve D-245 is adjusted in the following sequence:
Remove the cap of the cylinder head cover and check the mounting of the struts of the rocker arm axis;
Turn the crankshaft until the valves in the first cylinder overlap (the inlet valve of the first cylinder starts to open and the exhaust valve stops closing) and adjust the clearances in the fourth, sixth, seventh and eighth valves (counting from the fan), then rotate the crankshaft one revolution, setting overlap in the fourth cylinder, and adjust the clearances in the first, second, third and fifth valves.
To adjust the valve clearance, loosen the screw locknut on the rocker arm of the adjustable valve and, turning the screw, set the required clearance on the probe between the rocker arm and the end of the valve stem. After setting the clearance, tighten the lock nut. After adjusting the clearance in the valves, put the cap on the cylinder head cover in place.