Forged pistons for different brands of cars

Many of the technology transfer in the automobile industry of motorsports. Used there are decisions and details considered as models of reliability and performance, for example, forged pistons. Autotechnology, based on the use of these parts, refers to the patterns of use of sports solutions for civilian vehicles.

Definition

Pistons presented bushings oval shapes moving in a vertical plane inside the cylinder, compressing the fuel-air mixture. For the production technology of these parts are subdivided into cast and wrought. Take a closer look.

Features

The Pistons of the first type mounted on most vehicles because they are well manifest themselves in the daily operation and sufficient for the needs of most users. Forged pistons are designed to work at high loads, so they are used on sports and racing cars. That is, the design and features of the part identified on the basis of conditions of its functioning.

The Most heavily influencing factor in the pistons during engine operation is temperature. It leads to expansion of the metal and uneven: it is more pronounced parallel to the axis of the gudgeon pin and less in the plane of swing of the connecting rod. The result is uneven contact of the piston with the cylinder, resulting in accelerated wear. In critical cases appear a bully named details primatyvajutsja, with the result that the engine jammed.

In Addition, the pistons affect the inertial force and the pressure created by the gases inside the cylinder.

Production Technology

In keeping with the title, for the manufacture of cast pistons used the technology of casting metal. As a starting material is used silicon-aluminum alloy. It is placed in the matrix, giving an oval shape. Then the detail to fit the cylinder. The skirt make optimal barrel-shaped. To ensure resistance to high temperatures, the piston fills the inside temperature balance steel inserts

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Unlike cast, forged pistons are produced under the technology of stamping. Use insulated or liquid methods.

In the first case the matrix is filled with molten metal and deform it at a certain speed with the use of the punch. Thus get high quality billet. Her final treatment is carried out by mechanical means.

For the technology of isothermal forging use pre-prepared items. They are prepared from the rod consisting of a high-silicon aluminum, compressed through a die that allows you to improve the structure of the metal, removing the pores. Next, the matrix is heated up to 450 °With the workpiece is punched with the high-speed hydraulic press method. This technology consists in the application to the matrix of the efforts of 250 tonnes, while maintaining its temperature at a constant level. The result is a precise high quality parts.

Basic settings

For the proper choice of details to consider on vehicle parameters are correlated with features of the engine. The following are the main specifications of forged pistons

1. Engine Model. The easiest way to find details based on the brand of motor, as manufacturers typically produce such products under certain engine models. However, we must note that in this case they are designed for stock motors. That is, if you have changed any parameters of the engine, for example the machined cylinders pistons designed for him will not work. Then they are selected for other parameters (in this case primarily in size).
2. Size. When choosing the parts need to match their diameter with the diameter of a cylinder subject to thermal expansion.
3. Compression ratio. In the technical parameters of the pistons indicated a particular value of this index, it is intended for. If the engine is not stock, it also must be considered.
4. Mass. About the value of this parameter of the pistons described later. In General, the smaller the weight, the better.
5. Capacity. In the technical parameters of piston indicate the maximum value of the power which has enough reserve of strength. Do not install the parts on the engine with big performance, since the excess loads may result in their accelerated wear and destruction.

Differences from cast pistons

Standard counterpart of details to consider are the cast pistons. They work well on standard engines, but for many reasons are not suitable for power units of increased capacity. First, they are characterized by high mass. Second, cast pistons have a suboptimal shape. Third, these items with factory defects are represented by cavities, foreign inclusions, bubbles, which are invisible and are not seen during normal operation in the standard power units.

However, the increase in power leads to an increase of the loads (temperature and pressure) for many elements of the car, especially the engine. In such circumstances, the identified defects can lead to cracking or burning of the piston. This can occur, for example, after setting the crankshaft custom crank radius.

Advantages

The Positive impact of forged pistons for the engine parameters is due primarily to their small mass. The weight of such items by an average 50 grams less than the cast counterpart. For example, forged pistons VAZ provide complete saving of weight 400-600 g. This allows to reduce the inertial force inside the cylinder. As a result of this increased turnover, reduced mechanical losses, increased power. Besides, the reduced inertial load on other elements of the crank mechanism such as the crankshaft, connecting rods and liners. That is, increasing its share.

Also forged pistons are different from cast greater hardness. This figure is 120-130 units, whereas their civilian counterparts, it is equal to 80-90 units.

In addition, these parts are characterized by high strength and resistance to temperature exposure. So, thermocyclic stability it is superior to cast counterparts in 5-6 times. Due to this, forged pistons can withstand 2500 cycles of heating-cooling, while the civilian models only 400.

A Low coefficient of thermal expansion possible to reduce the thermal gap between the cylinder and the piston to 0.05-0.06 mm.

Form

To reduce the weight of the forged pistons have a special form. The use of the T-shaped profile does not affect the oil consumption.

In addition, on the basis of uneven thermal expansion (largely parallel to the axis of the gudgeon pin) some manufacturers produce models with oval shape, perpendicular to the axis of the gudgeon pin. Thus, when heated, the item acquires a round shape, in accordance with the shape of a cylinder. This ensures a tight fit them to each other, distributing the load on the surface and limiting the ingress of gases into the crankcase from the combustion chamber.

Disadvantages

The Main disadvantage of forged pistons compared to cast, consider the high cost, and the parts and installation. The high cost of the pistons due to the complexity of production. In addition, the need to seriously invest in their installation. This is because such complex work should be entrusted only to professional artists, and in this case a need not only to install but also to customize the items.

In addition, it is believed that forged pistons make the car more noisy in comparison with the original castings. However, this is true only for non-heated vehicle. This feature is explained by differences in coefficients of expansion. Based on the forged pistons to slightly increase the clearance with the cylinder wall. Therefore, a cold motor with these parts has a louder. However, after warming up, when the pistons are expanded, and thus the temperature gap decreases, the noise subsides.

Usage

As is clear from the above, use forged pistons for boosted engines. These parts influence many characteristics of power units. They enhance both performance and reliability.

Relevance

The Feasibility of using forged pistons instead of cast is determined primarily by the characteristics of the vehicle. For everyday conditions is enough cast parts. Wrought iron counterparts are usually installed in the engine tuning. Even in this case their use is not always appropriate.

These items are most often used in crossing low-power engines. Standard details of some sports motors have sufficient resource for non-extreme power boost. Therefore, the most common components for engines VAZ (e.g., forged pistons for "Field" and forged pistons on "a Priori").

These parts are used not only for cars. You can install forged pistons on a motorcycle. Tuning sports cars are also very common. Sometimes modify and simple motorcycles. For example, some set of forged pistons for Ural.

Principles on the use and cost

Often these details are used when installing the turbo. Moreover, in many cases their use is essential to preserving engine life, since it increases the temperature and load on details that often leads to burned pistons. Forged pistons for turbo engine typically used in crankshaft and H-shaped connecting rods.

In any case, when installing, to ensure the cooling of the skirt and bottoms of the described parts. For this set maslobazovaya injector.

The Price of forged pistons Niva (set), for example, starts from 4 500 rubles. For domestic bikes they're cheaper.