In detail: do-it-yourself repair of ball-bearing turbines from a real master for the site my.housecope.com.
The purpose of this article is to familiarize current or future owners with ballbearing technology in turbochargers.
Bushing turbine:
As is known in classic sleeve turbines, one of the most loaded parts is the thrust bearing
It is a bronze plate to which oil is supplied for lubrication and stops or a bobbin, who as they call it, which stand on the shaft and resting on this plate keep the shaft from axial movement.
This is necessary so that the turbine and compressor impellers do not rub against the turbine housing and do not wear out. With an increase in boost, the turbine shaft begins to experience axial pressure towards the turbine part, respectively, the load on the bearing plate increases and the stops, which at some point cease to withstand the load and begin to wear out.
This gives the turbine an axial play, which is wear. Over time, wear progresses and at some point the turbine impeller touches the housing with the blades, such a turbine has only a few days to live.
Any wear is uneven, the shaft is unbalanced, vibration appears and the turbine literally falls apart.
Another disadvantage of the hub turbine is friction inside the turbine cartridge, which leads to later spin up and more lag.
It is customary to say that a turbine on bushings is less responsive (spins up more slowly) than a ball turbine. Another disadvantage of sleeve turbochargers is picky about the quality and purity of the oil, the tendency to coke the oil on the shaft.
Video (click to play).
Another serious disadvantage that little is known about is the large amount of oil required to create an oil wedge on sleeve bearings. Large quantities of oil tend to leak not into the drain or sump, but through the shaft seals into the compressor or turbine section to the exhaust. This occurs from wear and coking of the O-rings on the turbine shaft.
Almost any bushing turbine that fell into my hands had oil leaks towards the compressor and turbine.
Now let's consider the design of turbines based on ball bearing technology:
In the 90s of the last century the Garrett company developed an alternative to its series of turbochargers - "T". By that time, the turbine and compressor parts were rather outdated, having an old-fashioned design. And also the main disadvantage is the large masses of rotating parts.
The decision was made to fully develop a turbine on an angular contact rolling bearing with completely new turbine and compressor wheels.
The main part of such a turbocharger is the bearing:
It is designed in such a way that there is no longer a need for a thrust bearing, and therefore rotating masses are reduced and the less friction, the earlier the boost is reached.
The bearing itself consists of inner and outer cages of the cage and the bodies of rotation of the balls themselves.
As you can see from the figure, the bearing is not simple, but a thrust one, that is, when axial loads are applied, the inner race does not allow the shaft to move to the side and touch the housing, and grease is supplied to the bearing through special holes
For this turbocharger, a specially new compressor (photo) and turbine wheel with a more open blade profile was developed (GT X series, and later GTX R series)
Thanks to this, the gases began to pass more freely, the back pressure dropped, and it was possible to reduce the size of the turbine section at the same power.
All this together with the redesigned compressor allowed to increase productivity by 15%, as well as to make the response faster.
It feels like a decrease in the response time to the gas pedal and an increase in torque in the zone of low crankshaft speeds. Many drivers who drive such vehicles have admired the excellent throttle response and the rapid, almost instantaneous power increase.
Another plus of such turbines is that the oil is supplied to the cartridge through a special nozzle (restrictor) with a selected cross-section, so that the oil is supplied exactly as needed to lubricate the bearing.
I think it’s not worth talking about the fact that such turbines practically do not let oil through.
However, it was not without a fly in the ointment - the bearing has a number of design flaws. (Consciously or not - we will omit it, now we are not talking about that).
The bearing cages are literally made of plastic. The author knows cases when they melted with an increase in EGT (exhaust temperature). The consequences are sad - the balls without support begin to fall out of the tracks, the shaft starts to dangle and cling to the impeller housing, the seals are worn off and the entire turbine becomes unusable.
Also, separators fall apart from banal pops in the muffler when fuel is poured and even simply from old age.
In general, the unit turned out to be quite reliable (withstands high pressures) and unreliable (there is a chance of damage to the plastic separator and failure of the turbine).
Although known designs from other manufacturers, where there are no such disadvantages. The clips are made of bronze, and there is a spacer spring, the purpose of which is to expand the clips, thereby taking out the backlash from this unit. Such a unit is quite reliable in itself, but the turbine in which it is installed has a number of other disadvantages, which will be discussed in a separate article.
The authors of this project have accumulated extensive experience in studying the design and increasing the service life of ball bearing turbines.
For many car enthusiasts who love power and speed, the question of buying a car with a turbocharged engine is very important.
In turn, the task of the turbocharger is to supply a larger volume of air to the engine cylinders and, as a consequence, increase the power of the latter.
The only drawback of such a useful element is frequent failure, so every motorist should be able to make at least minimal repairs to the turbine.
Structurally, a turbocharger is a very simple mechanism that consists of several basic elements:
General body of the node and snail;
Plain bearing;
Thrust bearing;
Distance and thrust bushings.
The turbine housing is made of aluminum alloy and the shaft is made of steel.
Therefore, in the event of failure of these elements, the only correct solution is only replacement.
Most turbine damage can be easily diagnosed and repaired. At the same time, the work can be entrusted to professionals in their field, or you can do everything yourself.
In principle, there is nothing complicated about this (we will consider how to dismantle and repair a turbine in the article).
As the operating practice shows, there are two main reasons for breakdowns - poor-quality or untimely maintenance.
If, however, a technical inspection is carried out according to the plan, then the turbine will work for a long time and without any particular complaints from motorists.
So, today there are several main signs and reasons for turbine failure:
1. The appearance of blue smoke from the exhaust pipe at the time of increasing revs and its absence when the norm is reached. The main reason for such a malfunction is the ingress of oil into the combustion chamber due to a leak in the turbine.
2. Black smoke from the exhaust pipe - indicates the combustion of the fuel mixture in the intercooler or delivery line.The probable cause is damage or breakdown of the TKR (turbocharger) control system.
3. White smoke from the exhaust pipe indicates a clogged turbine oil drain line. In such a situation, only cleaning can save.
4. Excessive oil consumption up to one liter per thousand kilometers. In this case, you need to pay attention to the turbine and the presence of a leak. In addition, it is advisable to inspect the joints of the pipes.
5. The dynamics of acceleration is "dulled". This is a clear symptom of a lack of air in the engine. The reason is a malfunction or breakdown of the TKR control system (turbocharger).
6. The appearance of a whistle on a running engine. The likely cause is an air leak between the motor and the turbine.
7. Strange grinding noise during turbine operation often indicates the appearance of a crack or deformation in the housing of the unit. In most cases, with such symptoms, TCR does not "live" for a long time and further repair of the turbine may be ineffective.
8. Increased noise in the operation of the turbine can cause clogging of the oil line, changing the rotor clearances and rubbing the latter against the turbocharger housing.
9. An increase in exhaust gas toxicity or fuel consumption often indicates problems with the supply of air to the TCR (turbocharger).
To repair the turbine with your own hands, it must be dismantled.
This is done in the following sequence:
1. Disconnect all piping that leads to the turbine. In this case, you should be extremely careful not to damage the node itself and the devices adjacent to it.
2. Remove the turbine and compressor volutes. The latter can be dismantled without problems, but the turbine volute is often attached very tightly.
Here, dismantling can be done in two ways - by the mallet method or by using the snail mounting bolts themselves (by gradually releasing them from all sides).
When performing work, you must be very careful not to damage the turbine wheel.
3. Once the work on dismantling the volutes is completed, you can check for any shaft play. If the latter is missing, then the problem is not with the shaft.
Again, slight lateral play is acceptable (but not more than one millimeter).
4. The next step is to remove the compressor wheels. Pliers come in handy to do this job. When dismantling, please note that the compressor shaft has a left-hand thread in most cases.
A special puller is useful to dismantle the compressor wheel.
5. Next, the sealing inserts are dismantled (they are located in the grooves of the rotor), as well as the thrust bearing (it is mounted on three bolts, so there are no problems with removal).
6. Now you can remove the liners from the end part - they are fastened with a retaining ring (sometimes you have to tinker when dismantling).
The plain bearings (compressor side) are secured with a circlip.
7. When performing dismantling work, it is necessary (regardless of the breakdown) to rinse and clean the main elements - cartridge, seals, rings and other components.
Once dismantling is complete, repairs can be made. To do this, there should be a special repair kit at hand, which contains everything you need - inserts, hardware, oil seals and rings.
Check the quality of the fixation of the nominal liners. If they are loose, then they need to be grooved and the shaft should be balanced.
In this case, it is advisable to clean the liners well and lubricate them with engine oil.
The retaining rings located inside the turbine must be installed in the cartridge. At the same time, make sure that they are in their place (in special grooves).
After that, you can mount the turbine liner, having previously lubricated it with engine oil. The liner is fixed with a retaining ring.
The next step is to mount the compressor liner, after which a well-lubricated liner can be inserted.
Next, put a plate on it and tighten it well with bolts (without fanaticism).
Install the dirt plate (secured with a retaining ring) and an oil scraper ring.
It remains only to return the snails to their place. That's all.
This article provides a general algorithm for disassembling and assembling a turbine. Of course, depending on the type of the latter, this algorithm will be partially changed, but the general course of work will be identical.
Well, if a serious breakdown is revealed, then it is better to immediately replace the old turbine with a new one.
In the absence of serious defects, the repair of the turbine takes no more than a few hours. But with the help of improvised tools and material prepared in advance, you can make a very high-quality and budgetary repair.
Installing a turbocharger on a diesel engine improves energy efficiency, torque, power and throttle response. Long-term operation and untimely maintenance lead to damage to the unit. If you have locksmith skills and tools, you can repair the turbocharger with your own hands. To do this, you need to study its device and familiarize yourself with the repair instructions.
Material content [open]
The unit consists of three main sections:
hot (turbine), working with exhaust gases;
compressor room supplying compressed air to the manifold;
cartridge (bearing unit) that transmits the torque from the turbine to the compressor impeller.
There is a control system in the turbine or compressor section that controls the operation of the bypass valve. The compressor impeller is put on the shaft, which is a continuation of the turbine. The bearings are lubricated through oil channels.
Given the not too complicated device and the high cost of the unit, repairing a turbine with your own hands on a diesel engine can save you a lot.
This need for repair is indicated by the following signs:
Increased oil consumption that enters the cylinders. This may be accompanied by the appearance of blue smoke from the exhaust.
Loss of power due to air entering through the pipe seals.
Change in the composition of the fuel-air mixture. This translates into increased fuel consumption and black smoke from the tailpipe.
Increased turbine noise due to wear on cartridge bearings.
If you notice at least one of the signs, it's time to check the operation of the supercharger and repair the turbine with your own hands on a diesel engine.
Do-it-yourself diesel turbine repair requires tools, parts and advanced locksmith skills. In their absence, it is cheaper to turn to professionals. Handcrafted assembly can lead to the ingress of grains of sand into the unit. As a result, it will permanently fail. If you are confident in your abilities, you can get to work.
Before you repair the turbine, you should prepare a repair kit. You will need the following details:
You will also need the following set of tools:
socket and open-end wrenches;
screwdrivers;
nippers with sliding jaws;
curly editing;
puller;
mallet.
This is enough to restore the turbine with your own hands.
Do-it-yourself repair of a diesel engine turbine of a passenger car or truck begins with its dismantling. To do this, you need to perform the following operations:
unscrew the bolts or remove the stoppers securing the compressor and turbine unit housings;
if the knot has become attached, it must be carefully "woken up" by tapping with a mallet;
remove the snail.
First you need to check the bearings of the cartridge: longitudinal play is unacceptable, transverse play is only very small. AND
The compressor retaining ring is removed using a sliding jaw pliers. In this case, the reverse side of the shaft is clamped by curly dressing.
When disassembling, do not forget about the left-hand thread on the shaft.