The cylinder gasket is mainly used to ensure the sealing between the cylinder block and the cylinder head joint surface to prevent air leakage and water leakage. Cylinder head gasket is in direct contact with high temperature and high pressure gas, so it is easy to be ablated during use, especially around the cylinder mouth curling. The burning of the cylinder head gasket will seriously deteriorate the working condition of the engine, and it is also easy to cause damage to certain related parts or parts.
How to judge the cylinder head gasket burnt and how to solve it!
Causes of ablation of cylinder head gasket
(1) Uneven tightening force of the cylinder head gasket or incorrect tightening method causes the cylinder head gasket to not smoothly cause blow-by on the joint surface of the cylinder block and the cylinder head.
(2) The cylinder head is warped and deformed, the surface unevenness of the cylinder body is too large, and the screw of the cylinder head is loosened, resulting in a loose seal.
(3) Improper driving operation method, accustomed to sharp acceleration, rapid acceleration and high-speed operation. Excessive pressure aggravates the erosion of the cylinder head gasket.
(4) The engine often runs under heavy load, premature ignition, engine overheating, knocking, etc., causing local high temperature and high pressure in the cylinder to ablate the cylinder gasket.
(5) The fuel injection is entering too early; the coke deposits in the combustion chamber are serious; the diesel is improperly selected.
(6) Cylinder gaskets are of poor quality and uneven thickness; there are air bubbles in the mouth of the bag, asbestos is laid unevenly or the hemming is not tight.
Cylinder gasket ablation failure phenomenon
1. Burning phenomenon at the lintel of the adjacent two cylinders: The engine power suddenly drops during operation, and the speed is obviously reduced; the body shakes severely and the exhaust pipe is slightly wronged; the engine is difficult to start after the engine is stopped or is extremely unstable when idling.
2. Burning phenomenon between the cylinder port and the cooling water channel: When the engine is running, the water temperature suddenly rises, the speed is dull, the power drops, and the cooling water consumption is too fast; the exhaust pipe is discharged, especially when it is idling. The exhaust gas is pale yellow; the oil level of the crankcase is raised, and the lubricating oil is emulsified seriously; there are traces of rust on the water inlet of the radiator. If the burn is severe, a large amount of cooling water will enter the cylinder, causing the engine surface to fail to start.
3. Burning between the cylinder port and the lubricating oil passage. Phenomenon: The oil pressure is unstable and the oil temperature rises too fast; there are bubbles in the lubricating oil, the color becomes lighter and there is diesel smell, the lubricating oxidation deterioration rate and consumption are too fast; when the diesel engine is low temperature, a large amount of blue smoke is discharged from the exhaust pipe .
4. Burning between the cylinder port and the edge of the air cushion. Phenomenon: When the burning loss is slight, the engine power drops and the acceleration is slow, especially when the load is heavy. The speed is unstable at idling speed and the body shakes severely; if the burning loss is serious, it can be detected in the upper middle of the cylinder. The rhythm of “chak, chak” sound.
5. Burning phenomenon between cylinder port and cylinder head bolt hole: engine idling is unstable; there is a slight “click, click” sound at the valve cover; cylinder bolts (female) are often loose.
First aid measures for cylinder gasket ablation on the way
The following first aid measures can be taken when the cylinder head gasket is found to be burnt while driving and there are no spare parts: remove the cylinder head gasket and check carefully. If a small opening is broken, it can be filled with tin foil in the cigarette box, tin waste platinum in the electrical appliance, or asbestos thread, etc. In the damaged area, it can be flattened and compacted carefully; if the damaged surface is large, dry cowhide pads or a piece of patch from the same part of the waste cylinder pad can be used as a substitute, and the vehicle will be repaired according to the technical specifications after returning to the field. The use and maintenance of the cylinder head gasket should have sufficient strength under the action of high temperature and high pressure gas, not easy to be damaged: it should also have heat resistance and corrosion resistance; it should have a certain elasticity, which can compensate for the flatness of the joint surface, and has a good Sealability; easy to disassemble and assemble, non-stick cylinder and long service life. At present, asbestos cylinder gaskets are widely used. The structure is asbestos with a metal wire sandwiched between them. The water holes are bordered by copper skin, and the combustion chamber holes are inlaid with copper skin to prevent high temperature ablation.
Precautions during installation and maintenance
1. Remove the cylinder head bolts and replace the cylinder head gasket, which must be done after the engine is completely cooled to avoid the cylinder head from flexing and deforming.
2. Check the surface of the cylinder head gasket for depressions, bumps, damage, etc.; check whether the flatness of the cylinder head and cylinder body meets the requirements, and then clean the cylinder head gasket, cylinder head and cylinder body, and dry them with high-pressure air to avoid dirt. Affect sealing.
3. The selected cylinder head gasket must be the original parts that meet the requirements (specifications and models) with reliable quality. Pay attention to the up and down direction marks during installation to prevent reverse installation and avoid human failure.
4. Tighten the cylinder head bolts according to the technical specifications. Since the center is symmetrically extended to the two ends, the bolts are tightened to the specified torque in 2 to 4 times; it is more reliable to tighten it once in the hot state.
5. Cylinder head bolts cannot be removed due to corrosion. Do not pry hard with iron to avoid damaging the cylinder head. You can pour kerosene into the cylinder head screw holes and soak for a while to remove them smoothly.
6. Improper storage of the cylinder head, careless disassembly and assembly, damage and deformation of the cylinder gasket, and improper cleaning during installation will lead to poor work, lax sealing and man-made failures, which must be paid attention to.
When replacing the cylinder head gasket, you must be patient and careful to operate strictly in accordance with the technical standards, especially in strict accordance with the order, tightening torque and tightening method specified by the engine manufacturer to tighten the cylinder head bolts. Only in this way can the high-quality seal of the cylinder head gasket be guaranteed. At the same time, it is necessary to analyze the causes of the cylinder head gasket ablation, eliminate related faults in a targeted manner, improve the operation method of the equipment, and avoid brutal operation, so as to effectively extend the service life of the cylinder head gasket.