How to replace crankshaft bearings without removing the engine
The uninterrupted operation of the power unit depends on the serviceability of each individual element. If a characteristic metallic knock is noticed during its operation, this is usually caused by wear or rotation of the upper/lower sliding element. In this case, replacing the engine liner is carried out quickly in order to protect the engine from major repairs.
How to replace bearings without removing the engine?
To replace the liners successfully, it is not at all necessary to dismantle the motor. If you are assured that it is impossible to get to them without removing and pulling the engine out of the hood, urgently change the car service center. But be sure to take into account one condition - the crankshaft (CV) should not be worn out. Otherwise, you won’t be able to do without removing the engine and completely disassembling it!
Without dismantling the power unit, it is easier to change the connecting rod bearings; it is more difficult to change the main bearings. For the latter case, you need to loosen the fastenings and release the crankshaft by 10-15 cm. Although there is another method, adopted by our grandfathers from ship motorists. The main bearings are pushed out using a soft rivet or bolt, which is inserted into the desired lubrication passage and rotated clockwise. The main thing is that the size of the aluminum insert should be slightly smaller than the hole and not scratch the crankshaft.
After removing the half rings, it is imperative to evaluate their condition. If there are no visible scuffs or damage, you can get by with a simple replacement. However, if it is very worn, polishing the HF is mandatory. Therefore, you will have to remove it from the mounts, and to do this, pull out the motor.
More information about condition assessment:
- pits or pockets - fatigue wear;
- scratches and ingrained dirt - low-quality motor oil;
- worn surface - insufficient amount of lubricant;
- chamfers on the edge - taper of the necks.
Restoration of crankshafts
You can also use a crankshaft restoration workshop, but I do not recommend restoring the crankshaft and having it welded on. I've heard a lot of disapproving reviews about restored crankshafts, firstly, these crankshafts break, secondly, they wear out quickly.
Photo. Broken crankshaft VAZ-2103, last boring crankshaft (liners size 1.00)
In the photo you see a broken crankshaft from the last boring; after boring this crankshaft and installing it on the engine, it covered 45,000 km before it broke. True, the owner of this six did not spare the engine much and gave it gas.
Therefore, if your car has a last-bored crankshaft, then don’t drive it, driving such a car should be calm.
Replacement procedure and marking of liners
Below are instructions for independent work. Replacing the engine liner will be faster and easier if you do it consistently.
- Place the car in a repair pit. Remove the power unit protective cover, if present. Place a jack under one of the drive wheels. Be sure to drain the engine oil.
- Remove exhaust pants and other components that interfere with work from below. Also unscrew the suspensions connecting the engine to the gearbox. Loosen the camshaft chain, remove the starter, and on some cars, the beam.
- Remove the oil pan bolts, nuts and studs.
- Rotate the wheel to move the connecting rods to the most convenient position for unscrewing the bolts. They are tightened with a force of approximately 3 kg, so you need to select the appropriate tool (usually a socket of the appropriate size with an extension). After tearing off the pins, you can continue to unscrew them by hand.
- Remove the half rings along with the connecting rod caps by pulling down. Be sure to check the condition of the internal surfaces of the half rings.
- Pull out the main bearings using a pusher - a bolt of a suitable size or rivet.
- Install a new set of half rings, tighten and reassemble everything in reverse order.
For quick installation of half rings, the connecting rod is completely raised up, moved to the side and lowered. Now nothing will interfere with the work, the sliding element can be inserted faster. Then the connecting rod is put in place.
It is important to tighten the fastener bolts tightly so that they do not loosen after the car has been driven for a long time and cause a malfunction, such as spinning. To do this, tightening is carried out at a specific moment:
The connecting rod bearings are marked with numbers directly on the head. After the initial grinding of the HF, bearings with a size of 0.25 mm are installed. After the second - 0.5 mm, and after the third - 0.75 mm. The latest size is 1 cm. There is no point in processing the crankshaft further.
To ensure that replacing the crankshaft liners without removing the crankshaft is successful, it is recommended to entrust the selection of parts to a specialist. It will correctly calculate the size and you won’t have to reinstall the parts again.
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Sometimes it becomes necessary to replace the main bearing shells on an assembled engine, and if everything is clear with the connecting rods, then replacing the main bearings becomes a rather difficult operation. But after watching this video, you can replace the main bearing shells without the slightest problem, you just need to take a small bolt or screw that will fit into the oil channel and with its head it pushes out the liner when the crankshaft is turned. If there is no oil channel in the journal, then the liner is pushed out with a thin screwdriver or a knitting needle. Subscribe to my channel “My leisure” where I post different videos about my life and not only
Subscribe to my channel “Earnings in the village” where I do breeding and keeping pets, as well as trying to make money on it.
Sometimes there is a need to replace the liners on the assembled engine and if everything is clear with the connecting rods, the replacement of the molars becomes quite difficult. But after watching this video you can replace the bearing shells of the main bearings without the slightest problems; you just need to take a small bolt or screw that will fit into the oilcan and his hat pushes the liner, when turning the crankshaft. If there is no oil channel in the neck, then the liner is pushed by a thin screwdriver or spoke.
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How to Change the Crankshaft Without Removing the Engine
How to change the front crankshaft oil ?
A leak in the front crankshaft oil seal is one of the most common failures associated with rubber elements included in the engine design. Oil seals are used to seal the points where the shaft exits the housing. In the case of the crankshaft, these elements are installed at the outlet holes of the cylinder block.
When is it necessary to replace crankshaft bearings?
The HF engine experiences heavy loads. Just look at the vibration on the axis, which invariably occurs during the operation of the crankshaft. It is clear that the sliding bearings also suffer, because they take the blow first.
- Physical wear is the main reason when an engine liner needs to be replaced. The surfaces of parts wear out, backlash and vibration increase. Naturally, in such conditions the engine is in danger of knocking.
- Rotation is the second reason. More details about this are written below.
Thus, replacement of liners is required in several cases. Problems can be judged by various signs. For example, by the absence or presence of abrasive inside the lubricant. Also, a symptom of half-ring wear is low interference when installing the connecting rod cap.
Regarding factors that lead to wear or turning:
- dirty or too viscous lubricant - impurities and abrasive particles reduce the properties of the lubricant, and in general its cleanliness is one of the key rules of prevention;
- constant overload of the internal combustion engine - you cannot drive for a long time at high speeds, from time to time you need to pause, slowing down to 80-90 km/h;
- incorrect installation of half rings during a previous repair - as a rule, this occurs due to weak tension (insufficient clamping torque), so tightening must be carried out using a torque wrench.
Rotated liners: what does this mean and why do they rotate?
Rotating the engine bearings is a change in their position relative to the crankshaft journal or block. As mentioned above, this is caused by the colossal loads to which the parts are subjected. Shifting the bearings from their place immediately negatively affects the flow of oil. His pressure worsens, starvation begins and the power unit is destroyed. And all because the half rings are equipped with holes that must clearly coincide with the channels for the passage of lubricant.
The main reasons for cranking
There are several known reasons that cause elements to rotate:
- banal wear - the end parts of the sliding bearings wear out (support collars, stops, antennae), which are no longer able to hold the parts in one place;
- weak, incorrect fixation of the covers - the half-rings must be tightened with a certain torque specified in the passport data.
And of course, this arises due to a violation of the design operating conditions of the plain bearings themselves. In other words, due to a large and uneven load. This happens especially often with half rings with weak tension.
Rotating sliding parts can cause big troubles and therefore requires urgent intervention. The most dangerous is the shift of the main bearings. In this case, the power unit will definitely need an expensive overhaul.
It is noteworthy that when the connecting rod half ring rotates, it is simply updated. However, it is wrong to do so - because the resource of the mating connecting rod-pin pair in this case is reduced by almost 70%. Therefore, it is necessary to replace the connecting rod itself, in which a broken lock can often be found. And the most optimal method of repair is considered to be boring the crankshaft and replacing the complete liners, along with the connecting rods.
How to repair a piston VAZ 2109
If wear in the cylinders exceeds 0.15 millimeters, the cylinders need to be bored and the pistons and rings replaced to the following repair size:
Replacement of a VAZ 2109 piston must be carried out taking into account the compliance of each piston class with a new piston ring. When choosing a ring, you need to pay attention to its markings:
- if it is absent on the parts, then the product has nominal dimensions;
- “40” - an increase of 0.4 millimeters in the diameter of the repair ring is marked;
- “80” - corresponds to the marking of an increase in size by 0.8 millimeters.
Piston repairs in a BC are performed as follows:
Cylinder wear is checked. Using a bore gauge, the diameter of the cylinder is measured in two directions—longitudinal and transverse—in four zones.
Measuring cylinder diameter with a bore gauge
In the area of the first belt there is practically no wear on the cylinder. Therefore, the amount of wear in the remaining belts of the part can be determined by the difference in diameters between this cylinder belt and the others.
Cylinder wear control belts
- If the amount of wear is more than 0.15 millimeters, the cylinders are bored to the closest repair size. It should be taken into account that the final operation for processing the cylinder is honing. Therefore, it is necessary to leave an allowance for processing of a diameter of 0.03 millimeters.
- After the final operation, the repair size of the piston and the diameter of the cylinder differed in the range of 0.025 - 0.045 millimeters.
- A new piston is installed.
- In the same way, all remaining pistons on the VAZ 2109 are replaced.
- The engine is assembled in the reverse order of disassembly after the last piston is installed.
The replacement of VAZ 2109 pistons is well shown in the video.
How to properly break in an engine after replacing a piston
Proper running-in of the car is of great importance after the entire piston engine on the VAZ 2109 has been replaced. This must be treated very carefully, as well as repairs
Particular attention should be paid to those units in which the parts are connected to each other by friction, and the efficiency depends on the optimal clearances with which they should be adjacent to each other. So:
- The speed of the car, after installing new pistons, should not exceed more than 60 kilometers in one hour per 1000 kilometers. This is necessary for grinding in parts that rub against each other.
- The main purpose of running in is to smooth out all micro-irregularities. This occurs by friction between the parts until their complete fit is ensured. Increased heating of engine parts occurs when there is high friction during “grinding in.”
- This indicates that the engine should operate with gentle, minimal loads.
The difference between main bearings and connecting rod bearings
The radical semirings sit in the lower cavity of the BC. They are also located in separate beds, like the connecting rod ones. Their purpose is to facilitate smooth rotation of the crankshaft and serve as supports for it when the latter is installed in the BC of the power unit. They are in direct contact with the root journals. On 4-cylinder engines, 5 main plain bearings are usually used. They are equipped with grooves and holes for better lubricant supply.
The connecting rod bearings are installed at the very bottom of the pan. They are pressed into the connecting rod (head) caps. Mounted on connecting rod journals. Compared to radical half rings, they have a simpler design.
Specialists and experienced drivers are able to distinguish wear of main and connecting rod bearings by sound:
- the main ones knock dully, a metallic clang is heard - usually during sharp acceleration or at idle;
- connecting rod ones are almost the same, but the sound is much sharper, and the frequency of the noise increases with increasing speed.
Selection of crankshaft liners
In most cases, the selection is entrusted to a specialist. But after studying the information in detail, you will be able to do this on your own. In addition to the fact that it is necessary to combine spare parts with the car model, the general condition of the vehicle is also taken into account.
Selection of main liners
Some useful recommendations for selecting a new HF when replacing the crankshaft liners:
- it is better to buy basic elements of the same color as the standard ones (used, old);
- Be sure to check the markings directly on the shaft.
A special identification color selection card is issued for main bearings. For example, for a 4-cylinder engine, the markings applied to the BC and the CV assembly are used. If marked C3, then you can install yellow and green elements. More details about the colors in the picture below.
And this is an identification card for 6-cylinder engines.
Selection of connecting rod bearings
And here, if the HF is new, the plain bearings are selected according to the diagram. If the color code is lost, you need to look at the markings on the connecting rod caps.
Below is an identification card for selecting connecting rod half rings for four-cylinder power units.
And this is the color map for 6-cylinder units.
The choice of bearings also depends on the antifriction coating. As a rule, it consists of several layers:
- biometallic with a steel base (1-4 mm) - lead, copper, zinc, tin, silicon and aluminum;
- trimetallic - lead, tin, copper.
Use the correct engine oil that meets all the requirements and approvals of the engine manufacturer. It is also necessary to update the filter promptly to prevent abrasive particles from entering the lubricant. It is also not recommended to overload the engine. All this will extend the service life of the liners by almost 2-3 times.
