Replacing the piston group in a chainsaw or trimmer
Repair of this level should always be balanced. In such small engines operating at high speeds, replacing one piston that is burnt out or jammed does not give a long result and, if necessary, the entire piston group must be changed. Therefore, you need to consider whether to continue using this saw or purchase a new saw.
If this is a professional model, then such a repair is worth doing, but if it is an old household model like the Husqvarna 40 and it has worked for more than ten or twelve years, it is not profitable to repair it. Because its repair will cost so much. the same as the purchase of a new saw, albeit not from Husqvarna, but for PARTNER P350XT CHROME, the cost of 165 is definitely enough. over, such saws are sold by Husqvarna, since PARTNER is its subsidiary.
But if you nevertheless decide to repair a chainsaw or a trimmer, then you need original spare parts that are not cheap. With proper operation of the engine, the first repair may not come soon and only the piston ring or rings will have to be replaced, depending on the model. But if the saw is jammed, then it is necessary to change the entire piston group. the cylinder, piston and rings.
It should be noted that Husqvarna 136/141 chainsaws have approximately a service life of 500-600 hours, Husqvarna 340/350. 1000-1200 operating hours, professional chainsaws at least 2000-2500 operating hours, subject to strict observance of the operating instructions. In fact, it is impossible to rely on these figures, since the real resource can differ significantly, both up and down. But roughly we can say that semi-professional saws work 3-4 times longer than amateur ones, and professional ones up to 10 times or more.
Of course, nothing is eternal, but it is one thing if you change the piston group, after many years of operation and it has worked out its engine hours, fully paid for itself, and another thing is that this saw was refueled, for example, with gasoline, without oil, and it jammed. Such a saw has to be repaired, since all other parts are normal.
Many firms deliberately inflate the cost of spare parts in order to buy new models. For chainsaws and trimmers, for example, from Stihl, spare parts are available in a larger range than on Husqvarna. Therefore, when choosing a certain model, find out how things are with spare parts.
Replacing piston rings on a VAZ 2107
If the power on the VAZ 2107 has significantly decreased, it is worthwhile to carry out the procedure for measuring the compression in the cylinders, if the compression level showed less than 10 atmospheres, then most likely something is in the piston group, namely in the piston rings. This procedure is best done in a garage with a pit. This photo report shows how the piston rings of the VAZ 2107 are replaced. The rings are replaced in the same way on the VAZ 2106. The complexity of this procedure is estimated as 4 out of 5.
First of all, before starting to replace the rings, it will be necessary to: remove the pallet and the cylinder head.
So, after the cylinder head and the pallet cover are removed, you can start unscrewing the nuts securing the connecting rod caps, for this you need a 14 head with a powerful knob.
Then carefully remove the cover and put it aside, and repeat the same procedure with the rest of the connecting rods.
After that, it is necessary to turn the crankshaft a little so that the direction of the connecting rod approximately coincides with the exit of the piston from the cylinder, that is, there are no strong distortions. And after that, we try to push the connecting rod bolt with our hand, so to speak, try to squeeze it out in the opposite direction.
If the whole thing does not give in with your hand, you can squeeze it out, for example, with a wooden hammer handle, then the piston should get out without much difficulty.
Carefully, so as not to scratch the surface of the cylinder, we finally pull the piston out.
Now it remains to remove the old oil scraper and compression rings from the piston. To do this, you can use your fingernail to pry over the edge of the upper ring and pull it out and the grooves.
And then turning the ring a little along the diameter of the piston, carefully remove it from the entire groove cavity.
In the same way, we remove the remaining rings of the VAZ 2107. To make sure that the rings are already badly worn out, insert them into the cylinder and measure the gap that is obtained between its ends.
It is imperative to clean the piston grooves before installing new rings. Installation is carried out in the reverse order, and first the oil scraper (the lowest) is installed, then the compression ones from the bottom up. The best way to do this is to use a mandrel.
Replacing the piston rings on the Zetec-E engine
Good afternoon, I decided to make an “easy” overhaul of the engine. The reason for this repair was the oil consumption, per 1000 km, about 1.5 liters, besides, after 3-5 thousand km the candles break through, the cylinders are constantly “wet”. Car FF1 Zetek 1.8.
Below is a list of required spare parts:
- Piston rings set Goetze 08-136600-00 (4pcs) 2 323.12
- Gasket, cylinder head cover ELRING 364.380 500.60
- Gasket, cylinder head ELRING 123.473 1 196.10
- Gasket, intake manifold REINZ 71-34322-00 (4 pcs) 390.80
- Oil scraper caps Elring 127.510 (8 pcs) 297.20
- Oil scraper caps Elring 127.490 (8 pcs) 289.84
- Oil filter Bosch 0 451 103 259 135.03
- Cylinder head bolts Febi 05541 (10 pcs) 458.00
- Formula F oil 1350,00
- AGA antifreeze 10 l. 900.00
- Sealant 120.00
- Kerosene 3 l. 250.00
_You will need: RUB 8,210.69_
1) We bully the face.
3) Remove the air conditioning compressor. No need to unscrew hoses.
4) We unscrew and cut off the pallet, be careful and remember that next to the crankshaft pulley you cannot drive the knife inward, since there is an oil receiver.
5) We unscrew the fastening of the intermediate bearing of the right drive. If it does not work, then you will have to drain the oil from the box, remove the wheel, remove the rack from the ball, and only then you can pull out the drive.
6) the 2nd pallet is also unscrewed and removed.
This ended the work from below, it remains only to unscrew the connecting rods.
1) Disconnect the terminals, remove the battery cover and the battery itself.
2) Remove the spark plug wires, coil fasteners and the coil itself.
3) The inlet pipe and filter housing are removable.
4) Drain the antifreeze, disconnect all hoses coming from the thermostat, remove the thermostat housing.
5) The coolant tank must be unscrewed, then taken to the side.
6) Unscrew the timing belt cover and remove.
7) Disconnect the wiring braid (injectors, camshaft sensor, kxx).
8) Remove the ramp.
9) Remove the generator.
10) Remove the throttle.
11) Remove the intake manifold.
12) Unscrew the bolt by 10, on which the generator fasteners are attached to the cylinder head.
13) Unscrew the power steering fasteners from the cylinder head.
14) We unscrew the tension roller, then we take it out.
15) Unscrew the valve cover.
16) Remove the belt.
17) Unscrew and remove the camshafts.
18) Unscrew and remove the cylinder head.
19) Unscrew the rods.
20) We take out the pistons.
21) Remove the rings.
22) Pistons need to be soaked in kerosene.
_Getting to work with the cylinder head: _
1) We take out the cups with washers
2) Dry the valve
3) Remove the springs and plates
4) We get the valve
5) Remove the valve stem seals
6) If the valves are dirty, then they need to be soaked in kerosene
Placing Piston Rings On a Stihl 54mm Clone Farmertec Cylinder Kit
Replacing the piston rings
Replace the piston rings after 70,000.90,000 km (depending on the operating conditions of the vehicle).
Piston rings are installed three on each piston: two compression rings and one oil scraper. Compression rings are made of special cast iron. The outer surface of the upper compression ring is porous chrome plated, and the surface of the second compression ring is tin plated or has a dark phosphate coating.
On the inner cylindrical surfaces of both compression rings, grooves are provided (Fig. 54a), due to which the rings are slightly twisted when the piston moves downward, which contributes to better removal of excess oil from the surface of the sleeves. Rings must be installed on the piston with grooves upwards, towards the piston bottom.
A. piston with rings of the UMZ-4178.10 engine;
b, c. piston with rings of the UMZ-4218.10 engine;
1-piston; 2-top compression ring; 3-bottom compression ring; 4-ring discs; 5-axis reamer; 6-radial reamer
The UMZ-4218.10 engine can be equipped with two versions of compression rings (Fig.54b, c).
One version of the upper compression ring 2 (Fig. 54b) has a groove on the inner cylindrical surface. The ring must be installed on the piston with the groove up.
Another version of the upper compression ring 2 (Fig. 54c) has a barrel-shaped profile of the outer surface, there is no groove on the inner cylindrical surface of the ring. The position of the ring when installed in the piston groove is indifferent.
Lower compression ring 3 (Fig. 54b, c). scraper type, on the lower end surface has an annular groove, which together with the tapered outer surface forms a sharp lower edge (“scraper”). The ring is produced in two versions. with a groove on the inner cylindrical surface of the ring (Fig. 54b) and without a groove (Fig. 54c). Rings must be installed on the piston with a sharp edge. “scraper” way down.
The oil scraper ring is composite, has two annular discs, radial and axial expanders. The outer surface of the oil scraper discs is hard chrome plated. Ring lock straight.
Piston rings of overhaul sizes (see Table 5) differ from rings of commemorative sizes only in their outer diameter. Oversized rings can be installed in worn out cylinders with the nearest smaller oversize by sawing their joints until a gap of 0.3 is obtained in the lock. 0.5 mm (0.3-0.65 mm for engines mod. 4218).
Check the side clearance in the ring joint as shown in Fig. 55. Fit the rings to the regrind cylinders on the upper part, and to the worn ones. along the bottom of the cylinder (within the piston ring stroke). When adjusting the ring, install the ring in the cylinder in the working position, i.e. in a plane perpendicular to the axis of the cylinder, to do this, advance it in the cylinder using the piston head. The planes of the joints when the ring is compressed must be parallel.
Remove and install the rings on the piston using the tool (fig. 56) model 55-1122.
After fitting the rings to the cylinders, check the side clearance between the rings and the grooves in the piston (Fig. 57), which should be: 0.050 for the upper compression ring. 0.082 mm, for the lower compression. 0.035. 0.067 mm. With large gaps, replacing only the piston rings will not exclude increased oil consumption due to the intensive pumping of oil by the rings into the space above the piston. In this case, replace the pistons at the same time as replacing the rings (see. “Replacing pistons”). Simultaneous replacement of piston rings and pistons dramatically reduces oil consumption.
When replacing only piston rings without replacing pistons, remove carbon deposits from the piston crowns, from the annular grooves in the piston head and from the oil drain holes located in the grooves for the oil scraper rings. Remove carbon deposits from the grooves carefully so as not to damage their lateral surfaces using a tool (Fig. 58).
Remove carbon deposits from oil drain holes with a 3 mm drill.
When using new or re-sized cylinder liners, it is necessary that the upper compression ring is chrome plated, and the remaining rings are tinned or formatted. If the liner is not repaired, but only the piston rings are changed, then all of them must be tinned or phosphated, since the chrome ring is very badly worn in to the worn liner.
Before installing the pistons in the cylinders, spread the joints of the piston rings at an angle of 120 degrees. to each other.
After changing the piston rings, do not exceed the speed of 45-50 km / h on the car within 1000 km of run.
How to fix a trimmer yourself
Trimmer repairs should be carried out as soon as possible at the first sign of breakage so that minor faults do not lead to more serious problems. All models are characterized by the presence of such basic units and structural elements: drive system (engine), transmission devices, working part (knife or fishing line), belts and handles. Failure can occur in any part, but some components fail much more often than others.
Lawn mowers powered by gasoline or electricity (as well as different models from different manufacturers) differ in design and nature of the problem. Some of them can be easily eliminated with your own hands, while others will require more overhaul or contacting a service center.
Disassembly of the gasoline spit, lubrication of its parts and replacement of faulty elements
To disassemble the lawn mower for repair work, you will need, in general, the following devices:
- a set of screwdrivers (with different tips) and wrenches;
- small puller for removing bearings;
- special candle wrench;
In each case, you will need to disassemble individual nodes.
It should be borne in mind that the starter (launcher) in a number of models is non-separable. in this case, in case of problems with it, only the replacement of the element is possible. If the knot is disassembled, then it can be repaired by removing and replacing the rope and spring, or reinstalling the latter (when it comes out of engagement).
Disassembly and repair of electrical parts
Disassembly of the electric scythe in order to repair its electrical part is carried out in the following sequence.
- Place the trimmer on a flat surface (such as a table) that does not contain unnecessary items.
- Unscrew the cover screws located on one side.
- Remove the unscrewed half of the case, gaining access to the start button, electric motor, brush assembly, bearings, electrical connections (these elements are shown in the photo below).
Disassembled electric trimmer
The brush and bearing units are shown in the photo below.
The braid will work without a thermal relay, only you will need to constantly independently check the temperature of the electric motor, periodically letting it cool down. You can also install a new similar sensor.
The start button of the electric motor can be checked by closing a jumper of its contacts. If the trimmer works, then the problem is clear. But this option is not safe. Everything should be done carefully so as not to get an electric shock. To change the button, you should use a screwdriver to remove it from the seat and connect the wires from the old to the new one. After replacement, you need to assemble the electric brace, and then check its performance.
Replacement of brushes is required if they have deteriorated. In this case, pull the old enough out of the grooves, and install the new ones in their place.
The connection terminals on different trimmer models are almost identical, so the connection and disconnection of the wires is the same.
Replacing the bearing is a rather difficult operation, because it can stick and not be removed from the motor shaft. Pull or knock it down carefully so as not to damage the rotor or seat.
Bearing for trimmer ET1003A
When the trimmer motor fails and needs to be replaced with a new one, carefully remove the fan and bearings and then reinstall them. In terms of costs, the replacement is almost comparable to the purchase of a new mechanism. In the absence of experience with electric motors, it is better to entrust its implementation to specialists.
When a knife or fishing line, when the engine is idling, almost constantly turns, and uncharacteristic sounds emanate from the front of the engine, this indicates a breakdown of the clutch. The reason is a broken spring. At the same time, the technique mows normally.
If slipping occurs, then in addition, the pads are worn out.
The trimmer clutch is repaired as follows:
- remove the cover from the muffler;
- remove the metal stand;
- then remove the cylinder and starter caps to gain access to the clutch;
- unscrew the side screws to remove the shock absorber cover;
- remove the tube from it, after letting the tightening bolts;
- unwind the clutch (shown in the photo below);
- inspect the condition of the spring, pads and bearings;
- the new spring is hooked by threading the hooks into the corresponding holes;
- to replace the pads, you need to remove the spring, and then unscrew the bolts on them.
If necessary, lock the crankshaft using, for example, a rope.
Parsing and replacing the rod
It is quite common to repair the trimmer bar. It is a construction of the following parts:
- a drive shaft made of steel with polyhedral or square splines at the upper and lower ends;
- aluminum tubes;
- a plastic sleeve designed to maintain the centralized position of the drive shaft in the tube (so that there are no vibrations);
- a rubber shock absorber needed to connect the rod to the motor;
- steering wheel with a handle used for steering and a rack, a belt.
On some models, a shock absorber is located between the steering column and the boom. All control elements (lock lever, ignition switch, gas button) are located on the handle.
A bevel gearbox is attached to the lower end of the boom, but some lightweight models are available without it. This is due to the fact that their bar has a curved shape, and the shaft is a flexible cable.
How to disassemble the rod and then assemble it to lubricate the shaft or replace it is shown in detail in the video below. In the same way, replace the broken barbell with a new one.
It often happens that the polyhedral or square splines of the drive shaft “lick”, while the operating mechanism does not rotate or does it with a slip. Then the shaft is changed.
When a knock appears in the tube, you should disassemble the rod and check the condition of the bushing, and, if necessary, replace it. How to properly assemble the throttle handle on the trim is discussed in the video below.
If the rod is not intact, suitable for installation, then you can tighten the place of the break with a clamp or apply a kind of tire. This is a temporary measure and should be replaced as soon as possible.
Repairing a gasoline engine, carburetor and gearbox
Engine problems can be caused by problems with the piston system, oil seals, rings. To eliminate them, it is necessary to remove the drive motor.
Determining what exactly caused the breakdown is not easy. If there is a guarantee, the mechanism should be taken to a service center for diagnostics and repair. If it is not possible to turn to specialists for help, then it should be borne in mind that replacement of piston rings is most often required. To do this, you need to disassemble the engine, get the piston. This is done in the following sequence:
- remove the cover of the plastic case by unscrewing the screws or wringing out the clamps;
- disconnect the bar with the crankshaft;
- remove the cylinder head;
- take out the piston and rings;
- if necessary, replace them;
- assemble in reverse order.
Rings should be installed carefully because they are fragile.
How the piston is installed and the oil seals are replaced during engine repairs is clearly shown in the videos below:
Regular use of the lawn mower can break the gearbox. Gears and bearings wear out in it (they can also break). To prevent this from happening often, this unit should be regularly lubricated. The frequency is almost always indicated in the operating instructions for the model used (at least once a season). The video below can serve as a repair manual.
To lubricate the gearbox, unscrew the plug and simply squeeze out a suitable lubricant inside the unit by turning the shaft.
The carburetor can only be removed and cleaned on your own, and the gasket between it and the engine can be replaced. It is rather problematic to determine the tightness of the assembly at home. The main thing is to correctly assemble the equipment after repair so that the trimmer works without problems.
The main malfunctions of gasoline trimmers
The most common are lawn mower breakdowns associated with such structural elements:
- engine (in particular with a piston system);
- starter (rope breakage, breakage or spring disengagement);
- with an ignition or fuel supply system;
- transmission mechanism (reducer);
- filters and silencer.
The symptoms are as follows:
- the appearance of uncharacteristic sounds during the operation of the lawn mowers;
- the lawn mower does not turn on, does not pick up the required speed, or stalls;
- when the engine is running, the working part does not rotate or slips;
- gasoline leak;
- excessive heating of individual units.
Also, minor breakdowns may occur, which are detected without any special diagnostics:
- sinking of the start button;
- falloff of the limiter;
- line breakage or breakage (loss of sharpness) of the knife.
Minor faults are not difficult to fix. Repairing a gasoline trimmer in more complex cases will require preliminary diagnostics to find out the exact reasons. If you have the appropriate knowledge and skills of locksmith work, then the problems can be eliminated independently, replacing the failed parts.
Lada Priora operation and repair
Piston rings and connecting rod bearings. replacement
Piston rings are replaced when repairing the connecting rod-piston group, when they are worn out or damaged. Also, the rings are replaced during engine overhaul.
To do the job, you need a piston ring mandrel.
Remove the cylinder head.
Remove the engine oil pan.
Turning the crankshaft by the bolt securing its pulley with a 17 mm wrench, set the piston of the first cylinder to the lower position.
Using the TORX EY wrench, unscrew the two nuts securing the connecting rod cover of the first cylinder.
Remove the connecting rod cover.
Resting the handle of the hammer on the piston, push it up.
We remove the piston from the cylinder.
We take out the liners from the connecting rod and its cover.
We fix the piston by the connecting rod in a vice. Opening the ring lock slightly, remove the upper compression ring. Similarly, remove the lower compression ring, oil scraper ring and its expander.
The rings are thin. so as not to break them, cut a strip from a plastic bottle with a length slightly less than the circumference of the piston. Place the edge of this strip under the lock of the upper compression ring, and then in a circle under the entire ring.
Remove the strip with the ring from the piston. Remove the second compression and oil scraper rings in the same way.
The feasibility of replacing the rings depends on the degree of wear of the cylinders. Small uniform cylinder wear (within 0.05 mm) can be compensated by installing a piston of another class with a large diameter.
We thoroughly clean the piston
from soot and deposits. We inspect the piston, connecting rod and finger. Cracks on them are unacceptable.
We select new rings in accordance with the piston diameter. nominal or overhaul size.
Before installing new rings, measure the gap between the piston ring and the groove wall into which the ring will be installed with a set of feelers.
Tab. 9.1.3 Permissible clearances between groove walls and piston rings:
|Upper compression ring||0.04-0.075|
|Lower compression ring||0.03-0.065|
|Oil scraper ring||0.02-0.055|
The permissible clearances between the groove walls and the piston rings are indicated in table. 9.1.3. If the clearance exceeds the maximum allowable, the piston must be replaced.
To select piston rings according to the thermal gap, we install the rings in turn into the cylinder of the block to a depth of 20-30 mm and determine the gap in the lock with a set of flat grooves.
The maximum allowable thermal gap during wear (for used rings) is 1 mm, the gap for new rings is 0.25-0.45 mm. If the gap exceeds the maximum allowable, the ring must be replaced.
We put the rings on the piston. In this case, the oil scraper ring
and set the compression ring with the inscription “TOP” up.
We install new rings on the piston, starting with the oil scraper ring expander.
With the help of a mandrel we put on the oil scraper ring, and then the lower compression ring (we put the rings on the mandrel and carefully move them down until they are installed in the groove).
We put on the upper compression ring without a mandrel: pushing the ring lock (no more than it takes to put the ring on the piston), we first put the lock on the piston, and then the back of the ring.
We turn their locks so that they are located at an angle of 120 ° relative to each other. The expander lock must be turned 180 ° relative to the ring lock.
Lubricate the cylinder wall with clean engine oil
and the outer surface of the piston.
We put on a mandrel on the piston and squeeze the rings with it, periodically tapping lightly with the handle of a hammer on the mandrel for self-aligning the rings.
The connecting rod caps are not interchangeable. The engine is equipped with “chipped connecting rods”, the covers of which are made by a special method. The contact surfaces of the cover and the connecting rod are uneven, which during assembly ensures a perfect fit of the parts.
We wipe dry the beds of the liners in the connecting rod and the cover, install the liners in them.
Lubricate the inner surface of the liners with clean engine oil.
Install the piston in the cylinder of the block.
The arrow on the piston crown must point towards the crankshaft pulley.
Pressing the mandrel to the block and tapping the hammer handle on the bottom of the piston, we sink the piston into the cylinder (while controlling the progress of the connecting rod to the crankshaft journal).
Install the cover on the connecting rod and tighten the bolts to a torque of 43.32—53.51 Nm (4.42—5.46 kgcm).
We collect and install the other three pistons in the same way.
After installing all the pistons, we assemble the engine in the reverse order.
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First of all, you need to disconnect the battery. After that, you will need to drain the coolant from the cooling system and the engine oil from the oil pan. Replacing the piston rings is possible in two ways: with and without removing the engine from the car. To determine whether it is necessary to remove the motor, a check will help: it is necessary to remove the cylinder head and visually assess the condition of the liners.
If signs of wear are visible on the cylinder walls (wear, any scratches or scuffs), the power unit will definitely have to be removed in order to bore the liners for the next repair size. If this is not done, simply changing the rings will not be enough, since they will quickly become unusable due to damaged cylinders.
If there is no production, new ones can be installed without removing the engine from the car. The stages of work on replacing piston rings, with the exception of dismantling the engine for restoration work, are the same.
Replacing the piston rings
The replacement process begins with dismantling the oil pan. Additionally, it is advisable to remove the oil pump and check how badly it is worn out. Then you need to unscrew the connecting rod caps and push the connecting rods with pistons up. It is important to remember that the connecting rod caps cannot be interchanged, each must subsequently be screwed to its own connecting rod.
The next stage is directly, replacing the piston rings. The easiest way to replace it is if a piston ring remover is available. It is a pliers that open the rings. The main thing is not to overdo it and not to unclench too much, since they can simply break. If there is nowhere to take a device for installing piston rings, you can do with a thin flat-blade screwdriver. The task, of course, will become more complicated, but you can cope with it. They must be installed with care so as not to scratch the pistons with a screwdriver.
Checking the condition of the removed rings will reveal the deformation of the cylinders. Uneven wear of the piston rings indicates that, during operation, the cylinders have taken an oval shape in cross section. In this case, it is advisable to squander them, since new parts will wear out heavily, and after replacement they will not last for a long time. You can change it in order to travel for some more time, but overhaul, nevertheless, will have to be done in the near future.
After removing the old rings, you need to remove carbon deposits from the grooves, which will interfere with the installation of a new set. The ideal tool for this procedure is a fragment of an old ring, so one of them needs to be broken. Also, carbon deposits must be removed from the piston crowns, if any. To facilitate the task, you can moisten the surface with kerosene. Act, again, you need to carefully so as not to leave scratches.
The installation procedure is as follows: the oil scraper ring is installed first, then the second and first compression rings. Due to the fact that the second compression and oil scraper rings operate in less severe conditions than the first compression, less stringent requirements are imposed on the metal from which they are made, therefore the rings are more fragile. Special care should be taken when installing them. It is almost impossible to accidentally break the first compression ring.
When installing, pay attention to the location of the piston ring locks: they should not be located in one line. It is best to place the lock of each next one at an angle of 120 degrees with respect to the previous one. Correct positioning of the piston rings additionally prevents gases from escaping from the combustion chamber into the crankcase.
The next critical stage of work is installing the pistons back into the cylinders. To put the pistons in place, you need a piston ring mandrel, otherwise they will prevent the pistons from entering the cylinders. It can be either universal, designed for pistons of different diameters from 50 to 150 mm, or made specially for a specific size. With the help of this device, the piston rings are crimped, after which the piston is driven into the cylinder lubricated with engine oil by gently tapping on the bottom with some non-metallic object.
Before putting on new rings
Before starting work, you need to acquire everything you need. The operation will require wrenches, heads, preferably with a ratchet, a torque wrench and a piston ring puller.
The packaging must contain complete information about them, namely: who is the manufacturer, what are they made of, etc. The rings must also have a mark indicating the top side, they themselves must not have any flaws, in addition, on the packaging or inside must be an instruction that describes the correct installation of the piston rings.
Correct replacement and installation of piston rings, signs of wear
The appearance of characteristic signs of engine malfunction, such as a sharp deterioration in dynamics, an increase in fuel and engine oil consumption, problems with starting the engine, especially in the cold season, indicates that the wear of the power unit has reached a limit, and further operation of the machine is impossible without outside interference. The listed signs indicate a sharp drop in compression. If the engine is not completely “ushatan”, then replacing the piston rings will most likely help to restore its vigor.
In order to save money, you can make a replacement yourself. In addition to the financial benefit, the owner of the car can be absolutely sure that the piston rings have been changed, moreover, for those that he bought, and the work is done with high quality. Unfortunately, leaving the car in a car service, the owner cannot know for sure how conscientiously the craftsmen did their job, since statistics stubbornly insist that they are deceiving everywhere, including on official services.
How to replace piston rings with your own hands is written in this article.
In short, the outline of the procedure is as follows:
- the cylinder head is dismantled;
- the condition of the rings is checked and the question of the need to remove the motor from the car is resolved;
- then the old ones are replaced with new ones, and the engine is assembled in the reverse order.
Further, each stage will be considered in more detail.
- Before putting on new rings
- Preparatory stage
- Replacing the piston rings
- Checking the performance and running in the motor
Checking the performance and running in the motor
After the engine is assembled, you need to make sure it works. It must be started and allowed to run for some time at idle. If it works steadily, we can assume that the work completed successfully. It should be remembered that new parts need a run-in, and the more accurately it is done, the longer the repaired power unit will last.
The run-in lasts 2-3 thousand kilometers. To prevent the replacement from going to waste, the following rules must be observed during running-in:
- the motor must not be heavily loaded;
- if possible, a full vehicle load should be avoided (ideally, the driver should drive alone);
- it is not advisable to overcome long climbs;
- it is absolutely impossible, especially during the first thousand kilometers, to raise the crankshaft revolutions above three thousand;
- the engine must be warmed up before driving.
How to replace piston rings yourself
Of course, replacing rings is a rather laborious procedure. It requires accuracy and certain skills, but by and large there is nothing complicated about it (if you do not remove the engine). For this you need:
- remove the cylinder head, observing all the recommendations of the car manufacturer;
- drain the oil, remove the flywheel protection and the engine oil pan;
- remove the oil intake;
- turning the crankshaft, set the desired piston to bottom dead center;
- unscrew the connecting rod cover and remove it;
- pull the piston together with the connecting rod out of the cylinder, pushing it up with a wooden rail;
- clean the piston from carbon deposits. According to its marking, establish the class of the piston, purchase a new set of piston rings corresponding to it;
- each new ring before installation is first inserted into the cylinder to check the gap in the lock. The clearance must correspond to the value specified in the vehicle manual. If it is less than necessary, then the ends of the lock are carefully filed with a file;
- pistons are thoroughly cleaned of carbon deposits. The oil drain holes are also cleaned with a suitable wooden stick. Cleaned grooves are lubricated with clean engine oil;
- put on rings starting with the oil scraper. On one side of the ring is marked “TOP” (up), which indicates how it should be installed in the piston. Locks should be installed 120 degrees relative to each other. This will exclude the penetration of gases through them. Do not wear rings with a “coil”, such an installation may be accompanied by the appearance of microcracks, which will lead to their breakage;
- reassemble in reverse order, cleaning everything in parallel with a clean cloth and lubricating with fresh engine oil. The pistons must be installed in exactly the same cylinders from which they were removed. Also, the connecting rod caps with connecting rod bushings must be put on the same connecting rods from which they were removed.
If the wear of the connecting rod bearings allows them to be reused, then it is not worth replacing, since this will require bore the crankshaft journals. You cannot do such work on your own without experience.
Piston Ring Replacement Guide
The fact that the car needs to replace the piston rings, and not some other repair work, will tell the engine itself. The signs of such a malfunction appear quite brightly, so it will be difficult not to notice them. But before talking about the symptoms, you need to understand what the rings are and what role they play in the engine.
Signs of wear on piston rings
The fact that wear has reached a critical stage is indicated by blue or black smoke from the exhaust pipe. This indicates that excess oil entered the combustion chamber past the oil scraper ring and burned there along with the fuel. Black smoke coming out of the crankcase ventilation pipe indicates that the compression rings, due to wear, allow gases to break through from the combustion chamber into its cavity.
Critical wear is accompanied by a decrease in compression (ability to hold pressure) in the engine cylinders. This means that part of the gases formed during the combustion of the fuel mixture, which was supposed to push the piston, broke into the crankcase without doing any useful work. This will lead to a drop in cylinder pressure, therefore, the engine will lose some of its power. Increased oil consumption is observed.
Compression is checked with a special device. a compressometer. When the nominal pressure values are unknown (there are no operating instructions), first it is measured in a dry cylinder, then a little engine oil is poured through the spark plug hole and the measurement is done again. If the compression increases, then the rings need to be replaced. Similar signs can be observed in the case of their “occurrence”.
“Stuck” occurs when carbon deposits formed in the piston grooves prevent the piston rings from springing, resulting in a decrease in their tightness to the cylinder surface.
Such a problem, if the case is not severely neglected, can be corrected with the help of special fuel additives. An engine that has a carburetor system can be cleaned with a carbon remover spray that is injected directly into the carburetor. If removing carbon deposits from the combustion chamber did not give an effect, then there is only one way out. replacing the piston rings and cleaning the grooves.
What are piston rings, their purpose
Piston rings are elastic open-ended elements that are installed in special grooves on the piston body. They are made of steel or cast iron of increased strength, and on top they are covered with an alloying material. Alloy coating further increases strength and also reduces wear rate.
Usually, 3 rings are inserted into the piston: 2 compression rings (occupy 2 upper grooves) and 1 oil scraper (lower groove). The purpose of the compression rings is to prevent hot gases from escaping along the piston into the crankcase. Oil scraper. removes excess oil from the cylinder bore, preventing it from entering the combustion chamber. In addition, the rings reduce the temperature of the piston by transferring almost half of the heat from its surface to the cylinder walls.
When the piston rings cease to cope with the tasks assigned to them, due to their wear, the car engine signals this by the manifestation of the corresponding symptoms.
Tools required for work
To replace the rings you will need:
- sets of open-end and spanner wrenches, as well as a wrench with an extension and heads with a face value of 10. 19
- torque wrench;
- specialist. crimp (mandrel).
You will also need an oil resistant sealant. It will come in handy during the installation of the oil pan and valve cover gaskets.
And there seems to be nothing complicated in the actions listed above, if the replacement is made without removing the engine from the car. However, there are nuances, without which the engine with new rings will not work for a long time. When a cylinder reaches the limit of wear, a “step” forms on the surface of its mirror. Having hit against it, the new ring will either break immediately, or get a crack, which in the end will still lead to its breakage. In addition, the grooves of the old piston also have wear, so lapping the new rings to the cylinder will be difficult or even impossible. This means that it is better to entrust the troubleshooting of the piston group and cylinders to professionals.
Cylinder boring and honing should also be done by qualified personnel. In addition, this work cannot be performed without removing the engine. Therefore, before getting down to business, you should think carefully, really assess your strengths and capabilities. So that the result of the repair does not become the replacement of the piston group as a whole, or even worse, it would not be necessary to take the engine for overhaul.