The formation of cracks on the surfaces of the parts of the power unit in the engine compartment is a common phenomenon and requires special attention. High thermal and physical loads in areas adjacent to the combustion chamber, including damage to the cylinder head (cylinder head). And if measures are not taken in time to identify and eliminate defects, then there will be a risk of more serious consequences. Therefore, as in heating systems, the basic diagnostic operation in this case will be cylinder head pressure testing, which allows the part to be checked for leaks.
In what cases is an operation performed?
Crimping is required not only if signs of a malfunction of the unit are detected. As part of a comprehensive diagnosis, this technology is used after repair work, replacement of individual elements and consumables of the engine structure, reinstallation, etc. With regard to specific symptoms, cylinder head pressure testing should be performed in the following situations:
- There are violations in the internal channels of the unit.
- Uncharacteristic overheating of the power unit is observed.
- If pronounced knocks and vibrations are heard in the part of the compartment with cylinders.
Timely conducted crimping makes it possible to fix the presence of a defect and take other measures to restore the structure. Most often, serious damage with leakage occurs after welding, when the seams are not processed enough and leak channels arise over time.
General crimping technology
Approaches to the technical organization of the process may vary depending on the conditions of the event and the availability of appropriate equipment. However, the principle of diagnostics by pressure molding is common to all methods. Its essence is to create a completely sealed vacuum in the cylinder and immerse it in a working fluid. Under conditions of increasing pressure, cylinder head pressure testing allows the detection of through holes, cracks and other defects. Moreover, the technology specifically for detecting faults does not require special equipment or measuring instruments. Final troubleshooting can be done visually. But the rest of the organization of the process is not complete without special equipment.
Applied Equipment
Previously, separate functional components were used for such tasks, which make it possible to organize a diving tank and additional process controls. Today, automotive equipment manufacturers offer special stands for crimping cylinder head, the basic set of which provides a complete list of necessary tools. A typical set is formed by the following units and devices:
- Heating elements.
- Lifting mechanism on frames with guides.
- Turntable with controls.
- Capacity with a cover.
- Sensors for monitoring pressure, temperature and starting.
- Electrical cabinet.
- Control Panel.
It is worth emphasizing the features of the materials used in the manufacture of the stand design. In addition to the stainless steel base, high-strength plexiglass, vacuum rubber and composite elements are used, thanks to which not only effective, but also safe crimping of the cylinder head is realized. Professional equipment is designed for many hours of work cycles, and the target service can be not only cylinders with heads, but also whole blocks.
Preparing the unit for operation
To begin with, you should perform a visual inspection of the part, which will allow you to identify suspicious areas and, possibly, more serious structural defects before crimping. It is recommended to fix in detail the dimensional parameters of the element with a ruler, further comparing the obtained data with the passport values. In case of deviations, basic mechanical refinement may be required. For example, crimping and grinding cylinder head are often combined into one technological process. Abrasive treatment portends a leak test, as physical exposure can reveal new areas of damage. The grinding operation is presented as the prevention of the detection of holes that, after pressure testing, are eliminated by spot welding.
Crimping Workflow
The capacity of the stand is filled with water, after which the work of the heating elements is activated. On average, it takes 2-3 hours to reach the optimum temperature of about 90 ° C, depending on the characteristics of the equipment and the volume of the tank. The diagnosed cylinder is closed by a vacuum shell, clamped by fixing devices and attached to the stand platform. It is worth emphasizing that all openings and outlet nodes are initially provided with plugs, which allows you to create a reliable vacuum. Next, the cylinder head crimping machine is connected to the product cavities by means of a fitting. Through this channel pressure will be applied with compressed air at 4-6 bar. At the final stage, it remains to immerse the structure in hot water, and then observe the release of air bubbles. The process of opening through cracks (if they are present) will certainly make itself felt under the influence of heat and against the background of expansion of the metal.
Do-it-yourself crimping with a bath
The implementation of the above method is possible in ideal industrial conditions, but not every private trader can afford to buy the same stand for immersing the cylinder in water. An alternative to organizing a procedure adjusted for home conditions may be the use of a bathtub, a plate for accommodating equipment and means for sealing the outlet openings of the product. A nozzle for supplying pressure is introduced into one of the channels, and then the same cylinder head pressure test is performed. With your own hands, you will need to immerse the cylinder in a bath with hot water and leave it there for 30-40 minutes. The pressure intensity can be adjusted using a pressure gauge. It is connected on the one hand to the compressor, and on the other - to the fitting. By increasing and increasing the pressure parameters, it is possible to more effectively examine individual sections of the structure, including identifying small cracks.
Do-it-yourself crimping without a bath
This is the easiest way, requiring minimal investment. It does not need a tank with additional monitoring and guiding equipment. It is enough to carry out external sealing of the cylinder and apply pressure water to the cavity. The disadvantage of this method will be low diagnostic accuracy, that is, small cracks may go unnoticed. How to crimp cylinder head without the same bathtub and special equipment, but with a sufficient degree of efficiency? For this, kerosene can be used as a filler. The output channels are also sealed, after which the capacity of the cylinder itself is filled with technical fluid. Due to its high penetrating power, kerosene will seep into the smallest holes, going outside.
Conclusion
Regularly checking the design of the cylinder block for cracks can cause a lot of trouble. Especially when it comes to the services of service centers, where the cost of preliminary diagnostics of the power unit will also be required. Of course, home crimping of the cylinder head in this regard will be a more attractive option. The main thing is to properly organize the technological process, which will allow to identify both large holes and microcracks. But even after troubleshooting, maintenance work on the cylinder does not end there. On the contrary, the crucial part remains the elimination of damage through welding.