Analysis of Cylinder Head Cylinder Head Leakage and Solution

1. 1 Observation method This method is inspected by seeing and touching. It is only suitable for serious cracks or cracks. However, due to trace leakage, there are obvious marks such as rust marks on the outside of the cylinder. Although this method is simple, it is difficult to detect small cracks. The oil immersion method should be used to find cracks that are not easily visible to the naked eye.

1. 2 Oil Immersion Method The oil dipping method is to first dip suspicious parts with kerosene or washing oil, and wipe them clean; then, sprinkle the white powder on them evenly, and then hit the cylinder with a wooden hammer. Due to the oil's penetration, the cracked white layer will show oil marks. Although the oil immersion method has the advantages of convenient operation and quick inspection, it is not convenient for the internal and uneven parts of the Cylinder Block.

1. 3 hydrostatic test method This method must be carried out in the state that the cylinder body and the cylinder cover are combined in accordance with regulations. The operating method is: plug the Water Pump inlet, the water pump outlet pipe with the compressed air (also through the hydraulic press). During the test, the water should be heated to full pressure. The pressure of the compressed air on the water is maintained at 0.3 M Pa 0. 5 M Pa and the time is 5 min. Observe the exterior and the part of the cylinder. Leakage site. The hydrostatic test is relatively slow, and it is necessary to observe carefully by visual observation to find the leak, and it is inevitable that the detection omission occurs.

1. 4 Air Pressure Test Method The test preparation work is basically the same as the water pressure test. The operation method is: clean the body and place it in a pool containing hot water, and then add compressed air to the water-free water jacket. The pressure is maintained. At 0. 3 M Pa 0. 5 M Pa. at this point there must be a bubble in the leakage area, and the size of the crack or trachoma can be determined by the degree of bubble generation. This method can not only identify leaks, endoleaks, but also identify oil leaks to the cooling system. Although this method is complicated, the leakage site is accurately searched for without omission, and has its unique advantages.

1.5 Leakage detection example A new 492Q engine has found organic oil in the cooling water at the initial stage and is showing a growing trend. According to this phenomenon, we used the air pressure test method to check, and indeed there was a bubble at the top of the vertical oil gallery of the cylinder head. In order to distinguish cylinder block or CYLINDER HEAD problem, we remove the cylinder head and remove one cylinder cylinder sleeve at the same time (because the vertical oil channel is on the side of one cylinder water jacket). In the water, the air pipe was used to apply compressed air from the oil passage on the upper plane of the cylinder block. After a short while, the hand extended into the bearing hole of the CAMSHAFT to block the vertical oil passage. Finally, the position of the trachoma between the oil passage and the water jacket was found.

2 cylinder block and cylinder head plugging cylinder block and cylinder head crack shape, length, depth, the location of the strength and temperature and other factors, is the main basis for the selection of plugging measures. Several plugging methods are described below.

2.1 Adhesive repair method Adhesives can be divided into organic and inorganic chemical compositions. Cracks in the non-forced parts of the cylinder block are generally of organic type. The most commonly used epoxy adhesives are those with a temperature of 150 or less. For the crack in the inner cavity of the exhaust passage with a temperature of about 900, the aluminum phosphate-copper oxide inorganic glue should be used. Whether the adhesive repair can achieve the long-term reliability of the adhesive, the key is the correct proportion and accuracy of the adhesive. Therefore, glue repair must be strictly operated according to the product specification.

2. 2 screw filling method This method can only be plugged and can not restore its strength, so the crack on the cylinder body (length less than 50 mm) can be filled with screw.

a. Drill limiting holes at both ends of the crack to prevent crack extension. The diameter of the hole depends on the diameter of the screw.

b. Drill several holes along the cracks with a 2/3 hole spacing and tap the threads.

c. screw into the threaded hole in advance screwed copper rod, screwed in part should be coated sealant, screwed into the cylinder 1. 0 mm 1. 5 mm at the saw off.

d. Drill holes between sawed screws and fill the cracks as described above. In order to prevent leakage, a hammer can be used to rivet around the screw and finally flattened.

2. 3 steel plate sealing method This repair method is applicable to cracks and small holes in the cylinder body where there are many and concentrated locations.

a. Drill limit holes at the crack tip.

b. Cut off a piece of steel plate 2 mm thick and 3 mm thick. If there is a convex-concave portion on the surface to be compensated, the same convex-concave shape should be knocked out on the patch plate in advance so that the entire patch plate and the complemented portion can completely fit.

c. Drill every 10 mm, 15 mm, and 10 mm from the edge around the patch. Drill and tap in the corresponding position of the cylinder.

d. Place an asbestos gasket coated with a sealant between the damaged surface and the patch, and tighten the patch with a flathead screw.

2.4 Weld repair method Weld repair method applies to cracks in the cylinder block where the crack is long or where the force is greater. The welding repair of cast iron parts is complicated and the technical requirements are strict. A slight carelessness can lead to scrapping of the cylinder block.

2. 5 Plugging Examples Example 1: There is a trachoma between the vertical oil gallery of a 492Q engine block and the water jacket. According to the suitable temperature of the epoxy resin and its corrosion resistance, the engine was implemented according to the product instructions. Slotted adhesive. After the engine has been loaded with a major repair mileage, it works well.

Example 2: A Dongfeng EQ 1090 truck has cracks in the vertical oil gallery of the cylinder block, causing the cooling water to leak through the oil gallery and the camshaft in the crankcase. In this regard, we used the method of inserting copper sleeves: first drill a deep chamfer with an electric drill at the upper and lower ports of the oil channel, and then find a copper pipe with a diameter of 10 mm and a length of 176 mm on the surface. After derusting, apply epoxy glue and press into the oil channel. Use conical tweezers to strike the hole on the copper pipe and lower hole respectively to make it firmly fit with the taper hole and finally make it flat. After the engine was repaired and loaded, it had traveled 20,000 km and the leakage failure disappeared.

In short, the selection of cylinder block and cylinder head cracks and trachoma plugging methods should be based on the premise of ensuring quality and long-term use, and should continue to be improved and adopt new technologies as soon as possible. For example, a listed cylinder blocker is a new material for repairing leakage of internal combustion engines. It has the advantages of ease of use, economy, etc., but it is not suitable for the cracks in the larger part of the cylinder.