How is the cylinder block lined? - today we will try to understand what is better than sleeves or coatings made of Nikasil and Alusil.
The debate continues about whether an aluminum block or a cast iron one is better. Progress is an unchanging thing in our world, so heavy cast-iron engines have been replaced by new light and aluminum ones. Manufacturers claim that aluminum blocks are superior to cast iron in all areas: they are lighter, not subject to corrosion, and thermal conductivity is 4 times higher than that of a cast iron block. Is everything so good?
Cast iron block
Most automakers follow the path of least resistance and try to reduce the weight of the cars they produce every year. And the replacement of the cast-iron engine, by the way, is three times heavier than the aluminum one, did not take long.
The cast iron block is a very durable element and has a low coefficient of friction between the cylinder walls and the piston surface. Maintainability is the middle name of a cast iron block. The cylinder walls are restored by boring and installing repair size pistons
Which motor to choose - cast iron or aluminum?
Over the past few years, it has become fashionable when buying a car to inspect its appearance, shape, interior design and many other functions.
Engines and gearboxes, as well as suspension, gradually began to remain in the background. This is not correct, since the car is not a TV or a smartphone, which after a while goes out of fashion. For any car, the engine becomes its heart, without which the implementation of its main function becomes impossible. But there are still drivers who carefully study its mechanical and technical parts before purchasing a vehicle. Many of them are faced with a difficult choice - which engine is better to choose - cast iron or aluminum?
Motors made of cast iron and aluminum. Recently, in the world of motors, the number of cars with cast iron engines has been decreasing. The result was the division of all car owners into two camps, adherents of one of which believe that aluminum engines are worse than cast iron ones.
At first glance, aluminum is better than ordinary cast iron. This is the reason that many experts and ordinary car enthusiasts are of the opinion that new engines are superior to old ones, with cast iron engines being defined as outdated technology.
Aluminum and cast iron engines are named after the material from which their cylinder block is made. If it is made of cast iron, then the motor has a corresponding name. It will turn out to be the same, even if it uses cylinder heads made of aluminum, its name will not change. The same applies to aluminum power plants.
Each type of motor has its own advantages and disadvantages.
Positive traits. The advantages include the following qualities:
- Significant reduction in engine weight, which affects the overall weight of the machine and fuel consumption;
- Due to weight reduction, the dynamic characteristics of the machine are increased;
- An aluminum block is less susceptible to corrosion;
- An aluminum motor cools down faster due to better heat transfer than cast iron;
- It takes less time for the engine to warm up;
- Improved optimization in conjunction with the turbine;
- Simplified processing of aluminum when the motor block is already cast.
Negative aspects of an aluminum motor. The disadvantages include:
- Difficulty in manufacturing. To cast an aluminum block, sophisticated technological equipment is required;
- The need to line the cylinder block or apply a special coating to protect the block from premature wear;
- Increased likelihood of defects at the factory;
- Accelerated cooling;
- Expensive repairs;
- Increased cost;
- The occurrence of galvanic corrosion.
The main disadvantage is the fragility of aluminum motors.
Cast iron motors also have some disadvantages. The main reason is the increased weight of the engine, which affects the level of fuel consumption, as well as the noise level and rough operation. In addition, a cast iron motor requires a long time to warm up and cool down.
Therefore, there is no way to be sure which motor is worse or better; each of them has its own positive and negative qualities.
“Dry” sleeve from the manufacturer
Engines Gamma 1.4 l. and 1.6 liters, installed on Hyundai Solaris and Kia Rio, are manufactured using the “dry” liner method - a cast iron sleeve with uneven outer edges is filled with liquid aluminum. A “dry” liner causes difficulties when repairing a block, unlike a “wet” liner where it is possible to remove the liner and replace liners and pistons.
Tandem pump
On engines with pump injectors, a so-called tandem pump is used. It consists of two sections. One section, the outer one, pumps fuel into the fuel rail. The inner section contains a vacuum pump.
This double unit often leaks fuel and the smell of diesel fuel appears in the cabin.
At the same time, diesel fuel can leak into the vacuum section and mix there with the oil that is supplied for lubrication. The opposite situation is also possible, when oil enters the pumping section.
The problem of the tandem pump leaking is solved by replacing its seals, which are supplied in repair kits. The repair kit also contains springs that need to be installed under the booster pump blades. The wear of these springs is indicated by poor and long engine starting, caused by a slow increase in fuel supply pressure. Normally, the booster pump should produce 7 bar.
Not all tandem pump problems can be solved with a repair kit. In its vacuum section there is a fitting that was unsuccessfully rolled on the conveyor. Often it becomes loose, and then the performance of the vacuum pump decreases, even the brakes become weaker. Air leaks into the vacuum section can be easily repaired by cold welding.
You can select and buy a tandem pump for a Volkswagen 1.2 TDI, 1.4 TDI, 1.9 TDI or 2.0 TDI engine in our catalog of contract spare parts.
Nikasil and Alusil
Thin-walled coatings (nickasil or alusil coatings) in theory, this method had only positive aspects, but in practice everything turned out to be much worse. Official version .
Most likely, the Nikasil coating technology turned out to be expensive and labor-intensive, with a high percentage of defects, which were attributed to high-sulfur gasoline. The second theory states that Nikasil and Alusil are a strong but thin coating located on the aluminum alloy of the block and at high temperatures are simply pressed into the aluminum.
Turbocharger
A Garrett GT1541V variable geometry turbocharger is responsible for pumping air into the 1.2 TDI PD engine. This version is known for cracking the cast iron turbine housing. Because of this problem, exhaust gases leak into the engine compartment and can be sucked into the cabin through the ventilation system. The welding of the crack most often does not last long, and ultimately the turbocharger assembly has to be replaced.
Wear on the shaft and bearings of this turbocharger rarely occurs, especially if the owner uses the correct and high-quality oil.
You can select and buy a turbine for a Volkswagen 1.2 TDI, 1.4 TDI, 1.9 TDI or 2.0 TDI engine in our catalog of contract spare parts.
Destruction of the braid on the electrical wiring of the injectors
The smallest turbodiesel with pump injectors can also present an unpleasant surprise in the form of one of the pump injectors turning off. Subsequently, the engine will operate with one cylinder disabled. The reason is standard: destruction of the braid on the electrical wiring, errors are recorded indicating a failure in the electrical circuit of one of the pump injectors. To eliminate this problem, you need to change part of the electrical wiring under the valve cover. It may also help to tighten the pins in the terminal of a specific injector.
Turbocharger geometry control valve
The turbocharger geometry of the 1.2 TDI PD engine is controlled by the solenoid valve N75 (1H0906627). Typically, due to a malfunction of this valve, the engine goes into emergency operation at a certain load. The fixed error clearly indicates a problem with the boost. When restarting, the engine usually runs normally and switches to emergency operation when the N75 valve malfunctions again.
You can select and buy an air electrovacuum valve (valve N75, valve N18) for the Volkswagen 1.2 TDI, 1.4 TDI, 1.9 TDI or 2.0 TDI engine in our catalog of contract spare parts.
Reliability of the 1.2 TDI engine
What can you say about the reliability of the 1.2 TDI engine? This engine inherited all the pros and cons of 4-cylinder engines with pump injectors. Essentially, this is a smaller and lighter 1.9 TDI engine with its own characteristics. Therefore, this small motor suffers from the same shortcomings. However, repairing this engine is not easy: if you have to remove the cylinder head, it is not a fact that the cylinder block will survive it. When the cylinder head screws are loosened, the main bearing caps are weakened, which can lead to deformation of the crankshaft bed. This is the information from the manufacturer.
Oil level sensor
The 1.2 TDI PD engine uses an oil level sensor that is not very durable. If it malfunctions, the ECU notifies you of a low oil level in the sump. In most cases, this alert is caused by a sensor malfunction. It needs to be replaced with a new one, although the method for repairing it is already known. You need to carefully heat and remove the plastic tube of the meter. After this, you will have access to soldering the contacts. You just need to re-solder the contacts and then assemble the sensor. As a rule, such repairs allow you to restore the oil level sensor.
Resource of pump injectors
Pump injectors have a good service life, and they can be diagnosed without removing them from the engine based on the actual parameters of their operation. All parameters of their operation are clearly visible in the diagnostic software, so a good diagnostician can determine the degree of wear and even find signs of the presence of air in the fuel system.
If the pump injector nozzle is worn out, it can be repaired, but if there are signs of improper operation of the control valve or wear on its seat, then the pump injector will have to be replaced.
You can select and buy pump injectors for the Volkswagen 1.2 TDI, 1.4 TDI, 1.9 TDI or 2.0 TDI engine in our catalog of contract spare parts.
Timing belt
As with all VAG engines with pump injectors, the timing drive uses a toothed belt of increased width - 30 mm. The camshaft pulley is equipped with an inertial vibration damper. Such a mechanism is necessary to reduce high loads and vibrations.
The camshaft pulley is composite; it is attached to the camshaft shank not directly, but through a hub, which is fixedly fixed on the shaft. When installing the timing belt, you can release the camshaft pulley, tighten the belt and then fix the pulley. This makes installation of the timing belt much easier and more accurate.
Injector seals
Much more often, pump injectors require attention to replace the rubber sealing rings that separate the fuel supply and return circuits. It has been noticed that if the seals of the rings are broken, air can get into the fuel lines. In this case, the diesel engine will operate extremely unstable and uneven. When diagnosing pump injectors on a stand, most likely no deviations will be found. Also, their nests in the cylinder head will be fine. The problem of poor engine performance will be eliminated by replacing the pump injector seals.
Camshaft wear
Engines with pump injectors are prone to wear on the camshaft cams. This problem occurs quite rarely on a 1.2-liter diesel engine. Let us remind you that to protect such an engine from camshaft wear, it is necessary to use oil with VW 505.01 approval (viscosity 5W-30) and change it every 10,000 km.
