How to Prevent Burnout of Diesel Engine Cylinder Cushion

Due to the rough operation and loud noise of the diesel engine, slight burning of the cylinder gasket is difficult to detect, and judgment is difficult, resulting in untimely replacement of the cylinder gasket (or repeated replacement and burning), resulting in deformation of the cylinder liner, damage to the sealing water blocking ring, and impact of high-temperature and high-pressure gas on the lintel between the cylinder head and cylinder block, leading to severe erosion of grooves, resulting in difficult maintenance and scrapping of components. Especially for imported engines with large compression ratio, high compression ratio, and high supercharging, it is more prominent. It has seriously affected the use economy and reliability of construction machinery. Based on the analysis of the phenomenon and causes of the burning loss of the diesel engine cylinder gasket, this article introduces the method of judging the burning loss of the cylinder gasket.

Characteristics, Phenomena, and Judgment of Cylinder Gasket Burning Loss

1.1 Burn loss at lintels of adjacent two cylinders

Phenomenon: During engine operation, the power suddenly decreases and the rotational speed significantly decreases; The body shakes seriously and the exhaust pipe has a slight grievance phenomenon; It is difficult to start the engine after stalling or extremely unstable at idle speed.

Judgment: If the engine is operated at a slightly higher idle speed and the personal heat share increases, smoke is emitted from his hole, indicating that the adjacent two cylinder cylinder gaskets are severely burned.

1.2 Burn between cylinder port and cooling water channel

Phenomenon: When the engine is running, the water temperature suddenly rises, the rotational speed is dull, the power drops, and the cooling water consumption is too fast; There is water vapor discharged from the exhaust pipe, especially when idling, the exhaust gas discharged is pale yellow; The oil level in the crankcase rises, causing serious emulsification of lubricating oil; There are traces of water rust at the radiator filler. If the burn is severe, a large amount of cooling water will enter the cylinder, causing the engine surface to fail to start.

Judgment: Fill the radiator with water, start the engine and accelerate suddenly. Observe the radiator inlet. If there are water bubbles or cooling water leaking outward at this time, it indicates that the cylinder cushion is burned. To further determine the burned position, you can remove the engine intake pipe, start the engine, and use cotton yarn and other materials to conduct an acceleration test at the intake port. If the phenomenon of water bubbles or cooling water flowing outward at the heater inlet decreases or disappears while accelerating, it indicates that the cylinder is thermally burned.

1.3 Burn between cylinder port and 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 a smell of diesel oil. The lubricating oil is oxidized, deteriorated, and consumed too quickly; When a diesel engine is cold, a large amount of blue smoke is emitted from the exhaust pipe.

Judgment: Start the engine and suddenly increase the rotational speed. Observe the oil pressure gauge. If the oil pressure is unstable and the pointer shakes severely while accelerating sharply, it indicates that the cylinder is thermally burned. To further determine the burning position, start the engine to medium, high, and high speeds, and remove the fuel injectors of each cylinder for testing. If oil is sprayed from the oil injector hole of a certain cylinder, it indicates that the cylinder gasket between the cylinder and the lubricating oil passage is burned.

1.4 Burn between the cylinder port and the edge of the air cushion

Phenomenon: When the burn loss is slight, it is manifested as a decrease in engine power and slow acceleration. The song of (how to disappoint me) is particularly obvious when the load is heavy, and the rotational speed is unstable and the engine body shakes severely when idling.

Judgment: The burning of the cylinder gasket often occurs at a higher temperature of the engine body (more on the exhaust pipe side). Generally, there is an obvious phenomenon of being washed by liquid at the burned parts, and yellow bubbles will appear when the engine is running. To determine the accuracy of the burn out position, start the diesel engine until the sound is evident at the rotational speed, and remove the high-pressure oil pipes of each cylinder. If the sound decreases or disappears while the oil pipes are removed for a certain cylinder, it can be determined that the cylinder is burned out; If it is difficult to judge the slight burning loss, evenly apply some engine oil to the joint between the cylinder head and the cylinder block. If there are bubbles, it indicates that the cylinder gasket is burned here.

1.5 Burn between cylinder port and cylinder head bolt hole

Phenomenon: Unstable idle speed of the engine; The cylinder bolts (nuts) are often loose.

Judgment: If the cylinder bolt (nut) often loosens when the engine is running, and carbon deposits are observed around the bolt hole on the upper end of the cylinder head and on the bolt, it indicates that the cylinder gasket is burnt here.

If the burned part is not obvious or light, and it is difficult to judge, evenly apply engine oil around the bolt hole, start the engine and accelerate suddenly. If bubbles appear, it indicates that the cylinder gasket is burned here.

In practical work, the burned part of the cylinder liner is often not a single occurrence, and its characteristics and phenomena are diverse. Therefore, comprehensive analysis should be conducted based on the actual situation to quickly and accurately determine the burned part.

2. Main causes of cylinder gasket burning

(1) The cylinder gasket bolts are loose, the tightening force is uneven, or the tightening method is incorrect.

(2) The cylinder head is warped and deformed, and the unevenness of the cylinder block is too large.

(3) The cylinder gasket has been used for too long and has insufficient elasticity. The quality of the selected cylinder gasket is poor, and the assembly is unreasonable.

(4) Premature injection timing; Serious carbon deposition in the combustion chamber; Improper selection of diesel fuel.

(5) Diesel fuel is out of warranty or improperly used. Such as frequent rapid acceleration with no load, frequent flameout at high temperatures, etc.

(6) Diesel engine maintenance, poor assembly quality, etc.