The crankshaft is a structural element of the engine that acts as an axle. It transmits the torque from the motor to the transmission, while maintaining heavy loads. Over time, the components of the crankshaft wear out - they become unusable, these are both bearings and seals, as a result of which the allowable gaps between certain nodes increase. All this leads not only to the appearance of noise and oil leakage, but also to a strong decrease in engine power.
In some cases, it is necessary not only to remove the crankshaft, install new components, as well as repair the components, and sometimes completely replace the crankshaft of the car, the cost of which is very high.
Reasons for replacing the crankshaft
In order to replace the crankshaft, in the right balance of price and quality, the car owner needs to thoroughly approach the choice of a car service where they will carry out this procedure. It is required to clearly imagine for what purpose it is planned to carry out the dismantling and installation of the crankshaft.
The reasons for replacing the crankshaft may be:
- traffic accidents, mechanical damage and deflection of the crankshaft - such situations can lead not only to the replacement of the crankshaft, which is a rather time-consuming and expensive service, but also require the installation of new pistons with engine cylinders;
- the desire to increase engine power, the acceleration period of the car and the speed of its movement - in this case, in addition to reinstalling the crankshaft, it will be necessary to install pistons and rings, and refine the cylinder head channels.
Checking crankshafts
The crankshaft of a car is one of the main parts of the engine. Its main task is to transform the translational movement of the connecting rods into rotational. The forces that act on the crankshaft are very large, so it is extremely important that it is always in working condition. When the first signs appear that indicate the poor performance of such an important component of the car engine as the crankshaft, you must immediately and immediately check it.
The main malfunctions of the crankshaft and the main reasons for their occurrence
Masters specializing in engine overhauls identify several main crankshaft malfunctions:
- Severe wear of the crankshaft main and connecting rod journals and the appearance of scoring on their surface, which occur due to a clogged oil filter, oil entering the fuel, insufficient pressure in the lubrication system along with an insufficient oil level in the crankcase, the use of those. poor quality fluids, severe overheating which leads to dilution of the oil or operation of the unit on dirty oil.
- Scratches and other visible damage on the surface of the connecting rod, as well as the main journals of the shaft, which usually occur due to the high mileage of the motor and the ingress of foreign particles into the technical fluid (oil).
- Crank deflection.
- Cracks in the crankshaft that appear due to the destruction of the connecting rod and piston as a result of any objects entering the cylinder or water hammer.
- The destruction of the keyways along with the seats for bushings and pins, which appear as a result of improper tightening of the bolts that attach the flywheels and pulleys.
- The destruction of the thread in the mounting holes, which occurs due to improper tightening of the mounting bolts.
Stages of checking the crankshaft
To check the crankshaft for defects, specialists carry out the following work:
You can check the crankshaft yourself, but it is still much better to contact a qualified specialist who will determine for sure whether it is possible to repair the crankshaft, or you already need to buy a new one and then install it.
Step by step when replacing the crankshaft
The crankshaft replacement work performed is quite lengthy and labor-intensive, so it is important to know what to expect from this procedure and understand what steps it consists of. It can be divided into several stages: the removal of old components and the installation of a new unit.
Removing crankshafts
The crankshaft is a motion converter in the KShM system, it rotates in the engine design on the main journals (5 bearings in a 4-cylinder engine). A large dynamic load causes wear of the journals (main and connecting rod), liners, and sometimes damage and distortion of the whole part. These are the main reasons for removing the crankshaft.
Many models of modern cars with reduced engine designs do not require the removal of the crankshaft or other components of the well-coordinated mechanisms of the car, guaranteeing a resource reserve of 200 thousand km. and more. Nevertheless, the features of KShM repair are well known in modern car services.
It is possible to successfully remove the crankshaft, make repairs and install it back only on a dismantled engine.
Removing the crankshaft:
- the car is installed on a lift, the oil pan is removed from it;
- the holder with the stuffing box is removed from the cylinder block;
- the drive cover with the gasket and the timing chain are dismantled;
- marks are made of the relative position of the connecting rods relative to the covers;
- the nuts that secure the connecting rod cover are unscrewed, the cover with the insert is removed;
- all connecting rods are disconnected from the crankshaft, moved up, the liners are pulled out of the covers and connecting rods;
- the bolts that hold the bearing caps are loosened;
- bearing caps are gradually removed and thrust rings are removed;
- the crankshaft is removed from the crankcase;
- the liners are replaced, the crankshaft journals are turned or replaced with a new one.
Crankshaft installation:
- the crankshaft is flushed with a special compound, then it is blown with compressed air and new liners are installed;
- the necks are lubricated with oil;
- the crankshaft is mounted in the cylinder block;
- bearing caps are put on, then the free play of the crankshaft is checked;
- connecting rods with liners, covers are installed on the crankshaft;
- then an engine oil pan is installed on the car;
- a holder with an oil seal is mounted on the cylinder block;
- all removed parts are put on in sequence;
- the timing is installed, followed by tension adjustment;
- the replacement of the tension generator or its adjustment is done;
- at the end, a diagnosis of correct operation is performed.
However, motorists who are little interested in overhauling the engine are often occupied with another question: Is it possible to replace the liners without dismantling the block?
The approach to repair, given the characteristics of the engines, may be different. By simply removing the pan and getting past the difficult access to the liners, there is a risk of more work being done.
The point is to replace the last of a series of parts, you need to decently lower the shaft, guaranteed to damage the seals. But first you have to “move” the gearbox by unscrewing the fasteners. Leakage and replacement of the camshaft oil seal after such intricate manipulations becomes a regularity.
The next difficulty is the difficult dismantling of the flywheel, which is securely fixed with a hard-to-reach flange on the crankshaft being removed.
In addition, it is necessary to check the crankshaft after grinding (sometimes multiple times) it is more efficient to do this on an inverted block. At the same time, you can clean the combustion chamber with valves, carry out preventive work.
Car crankshaft replacement: how much does it cost and where to do it?
Wanting to dismantle and install a new crankshaft, many problems arise, one of the main ones is the solution of the question: how much does it cost to replace the crankshaft? The price directly depends on many nuances: the general condition of other car systems, the goals of these works, the desire of the car owner to improve or simply update the crankshaft. In any case, this procedure will be costly and lengthy.
In the V-STUDIO car service you can check the condition of your car engine and all on-board systems associated with it, as well as replace the crankshaft and eliminate other detected malfunctions on favorable terms: in the shortest possible time, with a guarantee of high quality of work and materials performed and at reasonable prices
For the smooth operation of the car engine, every detail is important. A special position in the system is occupied by the crankshaft liners. Thin semicircular steel-aluminum plates surrounding the main and connecting rod journals are the outer races of the plain bearings, and the overall performance of the motor depends on their condition.
When is it necessary to replace the crankshaft bearings?
Under the conditions of those physical and thermal loads that the crankshaft has to endure, only plain bearings can keep it on the axis and ensure the operation of the crank mechanism. The main and connecting rod journals perform the function of internal clips, and the liners, respectively, are external. The engine block system has a network of oil pipelines through which engine oil is supplied to the liners under high pressure. It creates a thin oil film that reduces friction and allows the crankshaft to rotate.
Physical wear is the first and main condition, due to which it is necessary to change the liners. No matter how much we want to avoid wear, the surfaces of the necks and liners are gradually erased, the gap between them increases, the crankshaft gets free play, and the oil pressure drops sharply. All this leads to engine breakdowns.
Another reason for the forced repair is the situation when the crankshaft liners rotate. Every car owner has heard of such malfunctions, but not everyone knows how and why this happens. A thin plate of the liner is placed in the so-called bed. On the outer walls of the semi-rings, special antennae (protrusions) are provided, which, after assembly, abut against the end parts of the block or bearing caps.
Sometimes, when certain conditions occur, the antennae are not able to hold the liner and it, sticking to the crankshaft neck, rotates. If the crankshaft liners are turned, the motor cannot work. Typical causes of such a breakdown:
- too viscous lubricant, its absence, abrasive ingress;
- too little interference when installing bearing caps;
- insufficiently viscous lubricant and operation of the motor in overload mode.
Selection of crankshaft liners
Whatever the reasons for which the car owner is forced to disassemble the engine and change the liners, grinding the crankshaft is indispensable. New liners are installed either on a new crankshaft, or after grinding it. Even if only one neck is damaged or worn out, everyone undergoes grinding to a common size.
At the factory, when assembling the motor, standard liners are installed. For VAZ engines, liners of 4 repair sizes are produced. Accordingly, the crankshaft grinding can be carried out no more than 4 times. The step between the sizes is 0.25 mm. Accordingly, after the first grinding, it is necessary to buy liners marked "0.25", after the second - 0.5, after the third - 0.75, after the fourth - 1.0. Motors that are installed on GAZ and Moskvich cars have two more borings up to 1.25 and 1.50 mm.
The dimensions of the crankshaft liners that need to be purchased can only be calculated by a specialist who grinds the crankshaft. Sometimes it happens that damage to the necks requires grinding not to the next size, but through one. Bearings are only sold as a set for all main or connecting rod journals.
How to replace the crankshaft liners with your own hands
Considering that in order to access the crankshaft, you will have to completely disassemble the engine, you can only start such repairs if the car owner has the necessary knowledge and skills in this matter. First of all, you need to remove and completely disassemble the motor. This can be done in the garage, but this requires a complete set of car keys and others, as well as a mechanical winch. To remove the motor, do the following:
- remove the hood and ;
- drain oil and coolant;
- release the engine from attachments: starter, generator, fuel pump and cooling system pump, ignition distributor, remove the radiator and cylinder head;
- then unscrew the clutch cover, pillow nuts and remove the block;
- after laying the engine on a workbench, remove: flywheel, pulley, camshaft drive cover, oil pump drive chain and gear, auxiliary drive shaft, flywheel, and rear cuff holder;
- after 14 pallet bolts are unscrewed, the crankshaft itself will become available to us;
- in order to remove it, you will need to unscrew the bolts of the five main bearing caps and the bolts of the four connecting rod caps.
When removing the bearing caps, you can immediately see where the bearings have scrolled. It is strongly recommended that you do not remove the covers or remove the crankshaft until a specialist sees it. By the characteristic signs of uneven wear, the specialist will be able to determine where the displacement or curvature has occurred. To do this, it is necessary that each liner remains in its place.
Is it worth it to take on the installation of the crankshaft yourself?
The motor of a car is a rather complex and specific device. Many motorists successfully carry out its complete disassembly and repair. However, in order to properly install the crankshaft liners, you must have certain skills. It is better if this work is done by an experienced minder. This is necessary primarily in order to avoid excessive or insufficient tightness, which can cause the liners to rotate.
If the wear or ovality is greater than 0.03 mm, then the crankshaft journals must be ground in a specialized workshop where the necessary equipment is available (the axial runout of the main surfaces of the crankshaft must also be checked there). After grinding the crankshaft, we re-measure the diameters of the crankshaft journals to determine the repair size of the liners.
Installing the crankshaft on a car VAZ 2107
1. We wash the crankshaft in kerosene and blow its internal cavities with compressed air. We install new liners of main bearings of the crankshaft of nominal or repair size. On the outer cylindrical surface of the liners, numbers are engraved indicating the repair size: 025 - the first repair, for the crankshaft journal, reduced in diameter by 0.25 mm. Accordingly, for the second, third and fourth repair sizes, there will be values: 050, 075, 100. It is easy to distinguish between connecting rod bearings and main bearings. Annular grooves are made on the upper main bearings (except for the middle one). In addition, the middle bearing crankshaft bushings are wider than the others. The connecting rod bearings of the crankshaft are all the same and interchangeable, the diameter of the connecting rod bearings is less than the diameter of the main bearings. To increase the contact area, there are no annular grooves on the connecting rod bearings.
2. We install thrust half rings in the grooves of the bed of the fifth main bearing with grooves to the crankshaft. Half rings are made of normal thickness (2.310-2.360 mm) and increased (2.437-2.487 mm).
3. We check the axial clearance between the thrust half rings and the thrust surfaces of the crankshaft, which should be within 0.06-0.26 mm. If the gap exceeds the maximum allowable (0.35 mm), we replace the thrust half rings with new ones, increased by 0.127 mm.
4. Lubricate the connecting rod and main journals of the crankshaft with engine oil and install the crankshaft in the cylinder block.
5. In accordance with the marks, we install the main bearing caps and tighten the bolts of their fastening to a torque of 68.4-84.3 Nm. Check the free rotation of the crankshaft.
6. We install connecting rods with liners and covers on the crankshaft. Tighten the fastening nuts to a torque of 43.4-53.5 Nm.
7. We install the engine oil pan on the VAZ 2107 car (see "Engine oil pan - removal and installation").
8. We install a holder with an oil seal on the cylinder block (see "Rear crankshaft oil seal - replacement").
9. Installing the remaining removed parts on the VAZ 2107 car is carried out in the reverse order.
10. Adjust the tension of the timing chain (see "Timing chain - tension adjustment").
11. We adjust the tension of the generator drive belt (see "VAZ 2107 generator drive belt - tension adjustment and replacement").
12. On the carburetor engine of a VAZ 2107 car, we check and, if necessary, adjust the ignition timing
The crankshaft is a key assembly of the crank mechanism of an internal combustion engine. Thanks to the crankshaft, the reciprocating movements of the pistons are converted into mechanical rotation. The essence of the crankshaft is a crank that performs rotational movements around one fixed axis. Double the radius of the crank equals the length of the piston stroke. The crankpins are angled so that the cylinders work in pairs, but slightly ahead of each other. According to this principle, the crankshaft is arranged.
Crankshafts are made from high-strength steels or cast iron by casting, forging, machining. Due to the high compression ratio, the diesel engine crankshaft is subject to higher strength requirements. Otherwise, the crankshaft of a diesel engine does not differ in structure from the shaft of a gasoline engine. The crankshaft made of steel, especially machined, has a high cost, so cast iron crankshafts are more widely used.
The crankshaft consists of flat machined plates with counterweights (the so-called "cheeks"), which are interconnected by "necks". Counterweights are needed to dampen the reciprocating movements of the pistons and stabilize the rotation of the shaft.
On some modern engines, for additional stabilization, balance shafts with a displaced center of gravity and a drive from the crankshaft are used. They rotate in different directions, helping to balance the movements of the pistons.
In V-shaped and W-shaped engines, connecting rods from opposite cylinders press on the necks connected to each other. This allows for more uniform operation of the engine, reducing its dimensions. In in-line engines, each connecting rod is mounted on a separate neck with balancers.
The crankshaft journals have a cylindrical shape with a polished surface. Main journals are located along the axis of the shaft, and “rod journals” are located along the axis of the connecting rods. The rubbing pairs of the crankshaft, as a rule, are mounted on plain bearings. To prevent longitudinal displacements of the shaft, thrust bearings are provided, they are also called crankshaft half rings.
The crankshaft is located in the cylinder block in the reciprocal seats of the "crankshaft bed". A shank is located on the crankshaft for fastening the timing sprocket, alternator pulley and water pump. A flange for fastening the flywheel is fixed on the back of the shaft. A rolling bearing is installed in the flange, the gearbox input shaft enters it. Inside the crankshafts there are channels for forced lubrication of the bearings of the journals, connecting rods and the cylinder-piston group. The design of the crankshafts depends on the layout of the cylinders, their number. Drive gears for various equipment, such as an oil pump, can be installed on the crankshaft.
Malfunctions of crankshafts
Consider typical malfunctions of crankshafts:
- crankshaft oil seal leaks;
- "oil starvation" of working surfaces;
- mechanical damage to crankshafts;
- natural physical wear;
- abnormal increased physical wear and tear.
As a rule, the first thing motorists encounter is oil leakage from under rubber seals (crankshaft oil seals). This is a widespread problem on used engines. A leaking seal needs to be replaced. In some cases, changing the oil to a more viscous one will help stop the leak for a while.
For crankshafts, as well as for other engine parts, "oil starvation" is the most dangerous. The reason may be a breakdown of the oil pump, a clogged oil supply channel, low oil level in the engine. This leads to increased friction of the bearings, heating of the elements. Further operation of the engine in this mode will lead to its overheating, complete jamming and overhaul. A "wedge" on the move can lead to critical damage to the shaft or other engine components.
Water and fuel getting into the oil change its chem. composition and degree of viscosity. The reason may be significant wear of the cylinder-piston group, broken gasket structure, microcracks in the engine block or cylinder head.
Over time, the journals and bearings wear out, the allowable clearance increases, the crankshaft play appears, this leads to an increase in vibrations, the engine begins to “knock”. The characteristic knock of the engine is a critical signal. When it appears, you must stop driving and immediately contact a car service. If the crankshaft is out of balance or mounted incorrectly, increased abnormal wear on the contact surfaces may occur.
Crankshaft repair
Repair or replacement of the crankshaft is a laborious process. As a rule, it requires almost complete disassembly of the engine, inspection and troubleshooting of all its components and mechanisms. The crankshaft is removed and the axial runout is measured. In the case of acceptable wear of the surfaces of the journals and connecting rods of the crankshaft, they are ground to fit the repair dimensions of the bearings. The bed with the development is also subject to mechanical processing with “one installation” on a special machine. The crankshaft bore allows you to install the liner of the next repair size.
Neck sizes have repair tolerances. Simply grinding the crankshaft will not help if the wear or damage is too severe. The crankshaft is an expensive part, and if we are talking, for example, about large-sized agricultural machinery, the amount will be impressive. Even heavily worn friction surfaces can be restored. The thickness of the working is compensated by surfacing by electric submerged arc welding, plasma spraying of hard alloys, thermal spraying, etc. Then the crankshaft is ground, "brought" to the required repair dimensions. This is a technologically complex process, it is better to entrust it to specialists.
High-quality restoration and grinding of the crankshaft can provide 100% of its service life. It should be borne in mind that with an increase in the repair size, the crankshaft may move from its factory seat. You will need an accurate installation of the crankshaft with a selection of liners. A crankshaft with critical damage or axial curvature will have to be changed.
How to check the crankshaft? Experienced motorists can determine the characteristic knock of the crankshaft by ear using a medical stethoscope. During scheduled maintenance, you can remove the pan, visually inspect the crankshaft for cracks and chips, and use a feeler gauge to check the gaps between the half rings.
The increased content of metal chips in the filter and pan indicates wear of the friction pairs. In such cases, it is urgent to find the cause of the formation of such chips.
The diameter of the crankshaft journals can be measured with a conventional micrometer. The parameters of unbalance, runout and axial play of the crankshafts are determined using special indicators. To do this, either place the shaft on a special stand or machine, or install an indicator with a magnetic stand on the engine block. Measurement is taken while rotating.
To determine the clearance between the crankshaft journals and bearings, a calibrated plastic wire and a paper template with a special scale are used. The method is quite simple and affordable. A piece of wire is installed on the degreased surface of the crankshaft journal. To fix it, you can apply a small amount of thick lubricant. Then the neck is covered with a bearing and a cover. The covers are fitted, the wire inside is crushed on the plane of the neck (threaded connections must be tightened with a torque wrench). The bolts are unscrewed and the cover is removed. Next, it remains to measure the width of the flattened strip with a template. The value will correspond to a fairly accurate gap value.
Crankshaft replacement
So, how to remove the crankshaft? This will require a complete disassembly of the engine.
To replace you need:
- standard set of tools;
- torque wrench;
- crankshaft lock MR 1-233.
Removal of the crankshaft can be performed after dismantling the engine and installing it on a repair stand, timing units, engine equipment, cylinder head, connecting rods and pistons.
Scheme of assembly and installation in the engine block of the crankshaft Skoda OCTAVIA TDI 1996-2002 1,9,1315,17 - mounting bolts, 3 - flange, front pressure, 4 - bearing shell, 5 - chain sprocket, 6 - crankshaft shaft, 7 - bearing shell, 8 - crankshaft half rings, 10 - bearing cover, 11 - dowel pin, 12 - sensor wheel, 2 - sealing ring (oil seal), 14 - flywheel and drive disk, 16 - intermediate plate, 18 - sealing gasket (with gland).
The sequence of work to replace the crankshaft
1. Install crankshaft retainer MP 1-223 on the “crown” of the flywheel (it will prevent the rotation of the crankshaft). Position A for tightening, B for loosening.
2. Unscrew the flywheel fastening bolts 15, dismantle the flywheel.
3. Unscrew bolts 13 and, pulling out the dowel pin, dismantle the crankshaft sensor wheel.
4. Having unscrewed the bolts 1 and 17 around the perimeter, dismantle the clamping front flange 3, the front oil seal 2, the intermediate plate 16, the sealing gasket 18.
5. Loosen bolts 10, dismantle main journal covers, upper halves of bearings 7 and half rings 8.
6. Remove shaft 6 from the engine block, remove the lower parts of bearings 4 and half rings.
7. Troubleshoot, grind, balance the crankshaft. Clean the beds of the crankshaft and engine block.
8. Install the crankshaft in the reverse order of disassembly. When mounting the crankshaft position wheel, check the size of the excess of the locating pin 11 in accordance with the test diagram.
9. After installing the crankshaft in the engine block, check the beats.
There are a number of internal combustion engine concepts in which the crankshaft and connecting rods are replaced by other components. To date, a crankshaft with a standard layout is optimally suited for large-scale production, and “connecting rodless” engines are single experimental specimens.
If you have any questions - leave them in the comments below the article. We or our visitors will be happy to answer them.
How to remove and disassemble the crankshaft of a car - to remove the crankshaft of an internal combustion engine of your car, the following components and parts must first be removed:
1) side hatches of the crankcase block;
2) cylinder heads;
3) connecting rods with pistons;
4) flywheel;
5) tachometer drive;
6) flywheel housing;
7) cover for fastening units and gears;
8) pallet.
To press the crankshaft out of the engine crankcase, it is necessary to unlock and then unscrew the bolts that secure the crankcase covers from the flywheel side. Then, using a special puller (and if it is missing, with light blows with a copper punch on the end of the shaft), press the crankshaft together with the bearings from the crankcase block.
To disassemble the crankshaft, it is required to unlock, and then unscrew the bolts securing the sealing cover, remove the cover. Using the forcing bolts, remove the rear bearing from the shaft. Pressing the bearing out of the back cover of the crankcase, if not necessary, should not be. This completes the disassembly of the rear end on the crankshaft.
To remove the front ball bearing, you need to unlock, and then unscrew the clamping nut, remove the gear and spacer, remove the key; Using the forcing bolts, press out the ball bearing. Remove the plugs of the necks of the shaft and clean the cavities of the necks from sediment; wash the crankshaft and its parts in kerosene, clean all oil channels with a syringe, then blow it with air.
To remove the engine flywheel, unlock it, and then unscrew the bolts securing the flywheel to the crankshaft flange, screw a special puller to the flywheel with two bolts and, turning the pressure bolt with a wrench, remove the flywheel from the crankshaft flange.
When the above components and parts are removed, the yoke fastening nuts are unpinned, the yokes are removed, and then the crankshaft. After that, the plugs of the necks of the shaft are removed and the shaft and its parts are washed in kerosene. The oil channels are flushed with a syringe.
When inspecting crankshafts, the main attention should be paid to the condition of the main, as well as connecting rod journals and bearings, fillets, shaft cheeks, and on the engine crankshaft, inspect the shank, shank thread and clamping nut thread for the absence of cracks and nicks.
Insignificant circular risks are cleaned with a small sandpaper with oil, nicks are cleaned with a whetstone and a small sandpaper. A clogged thread is corrected with a file.
Inspection of the necks on the crankshaft is carried out:
a) connecting rod - in two belts;
b) radical wide - in three belts;
c) indigenous narrow - in one belt.
When inspecting the liners of main bearings, as well as connecting rod bearings filled with lead bronze, you should especially carefully examine whether there are gaps between the lead bronze and the steel bed, chipping or cracks. In case of detection of cracks, chipping or lagging behind the filling, the liners should be replaced. If there are scratches, burrs and small nicks, carefully clean these places with a scraper and iron with a trowel.
How to remove and disassemble the crankshaft of a car - in engines, you need to pay special attention to the condition of the bearing on the flywheel side. In case of significant wear, it must be replaced. When inspecting the crankshaft gear, attention should be paid to defects characteristic of the working surfaces of the gears: cracks, general wear, wear, chipping, burrs, as well as the presence of cutting teeth from the gear working in pairs. A worn out gear needs to be replaced.
Coupling bolts with nicks, elongated threads and clogged threads must also be replaced. The condition of the ball bearings should also be checked. The most serious defect in ball bearings is cracked balls. Cracks can occur during careless assembly, from the ingress of metal particles, as well as when the engine has been misaligned or carelessly aligned with the drive unit.
You should establish the absence of crumbling and scratches on the balls. The presence of pox-like spots on the surface of the balls or the cage indicates the presence of acids in the lubricating oil. Excessive wear of the clips may be the result of unsatisfactory quality of the lubricating oil. In case of overheating of the bearings in operation, the balls lose their luster, but this is not a reason for rejecting the bearings.
The presence of rust spots on the bearings indicates the presence of water in the oil or the ingress of moisture from the outside. The presence of defects such as chipping, deep local and: ring workings and large backlashes is, of course, the basis for replacing bearings with new ones.
After removing the ball bearings, as a rule, the spacers have to be replaced with new ones. Before assembly, the crankshaft should be very thoroughly cleaned and well washed, check for burrs and dirt in the internal holes. After installing the plugs, the shaft must be subjected to a hydraulic oil pressure test for five minutes.
After a hydraulic test, the nuts on the plug bolts must be locked by making cuts on the bolts. Oil channels must be protected from foreign bodies and clogging by tying the necks with cuffs made of pressboard or cardboard.
The drive gears of the crankshaft must be firmly seated on the shaft, however, care must be taken to ensure that their fit is not due to a tight fit on the key. The clamping nut must be locked with a folding washer.
The sealing cover with its shoulder should press the outer race of the bearing, and along the plane of connection with the cover it must ensure a close fit through the paper gasket, and the cover must be installed so that the cutout on the centering shoulder for draining the oil is at the bottom. When turning the bearing, the flinger must not touch the sealing cap.
It is necessary to check that when the shaft is turned, the rotation of the bearings is free, without jamming the balls.
When laying the engine crankshaft, the main journals, as well as their bearings, must be generously lubricated with oil, put the yokes in place and evenly tighten the bearing nuts. Start tightening, you need the nuts from the middle bearing. After tightening each bearing, try turning the shaft by hand. The crankshaft should turn easily by hand with all main bearings tightened.
After making sure that the shaft rotates easily, all bearing nuts should be cottered. In the future, the assembly should be carried out in the following order: put the pan, flywheel housing, install the gas distribution. After installing the flywheel, be sure to check with the indicator its runout on the end face and the outer diameter of the rim.
We have described how to remove and disassemble the crankshaft of a car, good luck!
Now great tips and tricks on the video How to remove and disassemble the car crankshaft and then install it correctly in bed
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