Maintenance for Marine Diesel Engine Cylinder Liner

Causes of strain on ship cylinder liner
Features: There are longitudinal pull marks and furrows of different depths on the inner surface of the cylinder liner.
Reason:
1. The oil selection is unreasonable or oxidized and deteriorated, and the pressure is too low.
2. The fuel supply is too large or the injector fails, causing overheating.
3. Cooling system failure. If the coolant is insufficient, the components of the cooling system fail, causing high temperature.
4. The engine is overloaded.
5. The “three filters” are invalid or improperly maintained.
6. Improper assembly and unclean cleaning of related parts.
7. Frequent cold starts.
8. Low temperature and low rotation speed for a long time.

Cummins Marine Liners, VASA Marine Liners, Wassilan Marine Liners, Waukesha Marine Liners, CRRC Marine Liners, CSR Marine Liners, CNR Marine Liners, Dachai Marine Liners, Weichai Marine Liners Cylinder Liner, Shaanxi Marine Cylinder Liner, Hechai Marine Cylinder Liner, Jichai Marine Cylinder Liner, Jinchai Marine Cylinder Liner, Qiyao Marine Cylinder Liner, Xinzhong Power Marine Cylinder Liner, Yichang Diesel Engine Marine Cylinder Liner, Medium and High Marine Cylinder Liner , Shangchai marine cylinder liner,

Ship cylinder liner partial wear, lifting
Ship cylinder liner partial wear, lifting

Features: There is obvious local wear on the top dead center of the piston stroke on the working face of the cylinder liner.
Reason:
1. The piston and cylinder liner are poorly aligned, resulting in partial friction.
2. The bending of the connecting rod is caused by the partial friction of the piston running in a twisted state.
3. The connecting rod is bent, and the overtravel of the piston causes local friction on the upper part of the top dead center.
4. The “three filters” fail, causing dust and impurities to enter the cylinder to form abrasive wear.
5. When the engine combustion is insufficient, excessive carbon deposits will be formed and abrasive wear will be formed.
6. The lubricating system is not good, and the lubricating oil film cannot be formed, resulting in poor lubrication of each friction pair.
7. The cleaning is not clean, and the running-in is not carried out according to the technical requirements.
8. The piston ring is installed backwards.
9. The lubricating oil is of poor quality.
10. The working conditions are bad, and it will be put into overspeed and overload operation without running in according to the regulations, which will cause the working surface to wear rapidly.
11. It has been used for a long time and has exceeded the normal use period, which is a normal replacement.

Pierstick Marine Liners, Daihatsu Marine Liners, Kobe Marine Liners, Roston Marine Liners, Yanmar Marine Liners, S.K.L. Marine Liners, Skoda Marine Liners, Mark Marine Liners, EMD Marine Liners, Makita Marine Liner, Stoker Marine Liner, Fiat Marine Liner, MAN Marine Liner, Sulzer Marine Liner,

Characteristics and Causes of Cavitation of Marine Diesel Engine Cylinder Liner
Feature:
1. There are honeycomb holes on one or more sides of the outer wall of the cylinder liner.
2. The outer wall of the cylinder liner is in the form of snowflakes, and the diameter is generally about 1cm.
3. The side with higher pressure on the piston side is the most serious.
Reason:
1. The engine works rough, causing high frequency vibration.
⒉. The body is deformed, and the cylinder liner and the body are skewed due to improper installation.
3. The coolant temperature is not suitable, the water flow is small, and the direction and speed change drastically.
4. Excessive coolant minerals and chemicals.

What effective measures should be taken for the wear of marine diesel engine cylinder liner
The early wear of the diesel engine cylinder liner will lead to a decrease in the power of the diesel engine, difficulty in starting, an increase in oil consumption, and an automatic flameout of the diesel engine in severe cases. The main location: the top dead center of the piston ring.
There are generally three types of cylinder liner wear: – Adhesive wear, which mainly occurs when the diesel engine is working at high speed and overload, and is caused by harsh lubrication conditions; Second, corrosion wear. The sulfide in diesel is the cause of corrosion wear. The main reason; the third is abrasive wear. Mechanical impurities enter the cylinder to form abrasives and adhere to the surface of the cylinder wall.
The reason for its formation:
①The running-in is not in place and put into use in advance.
②Long-term overload operation or idling operation, the lubrication is not good.
③ If fuel is supplied in advance or the accelerator is slammed, the ratio of fuel to air is out of balance, and the combustion is incomplete, resulting in carbon deposits.
④ Frequent starting, insufficient oil supply, dry or semi-dry friction, and accelerated cylinder liner wear.
⑤ When EGR (exhaust gas recirculation system) is used, acid substances are produced in the cylinder, which corrodes and wears the cylinder bore.
⑥ Air filter problems or oil aging, resulting in abrasive wear or low lubrication.
⑦The connecting rod is bent, twisted, loose or too tight of the matching parts, resulting in mechanical wear.
⑧ Cylinder liner material problem.
Its preventive measures:
1. Newly installed or newly repaired engines must undergo a strict running-in test run.
2. Regularly check and maintain the three filters.
3. Regularly replace the oil, clean the oil pan and lubricating oil circuit.
4. It is strictly forbidden to start first and then add water, otherwise the cylinder will be quenched and cracked easily.
5. Always maintain the normal working temperature of the engine, and it is not easy to be too high to prevent the oil from changing.
6. Pre-lubrication must be carried out when starting the engine to prevent dry friction and semi-dry friction.
7. After starting the engine, preheating for a period of time, the temperature of the engine reaches 40°C to start, and 60°C is officially put into operation.
8. It is forbidden to run the engine rapidly for a long time, or start it frequently to prevent uneven mixing of fuel and air, incomplete combustion, carbon deposition, and aggravating cylinder wear.
9. It is strictly forbidden to blast the accelerator, otherwise it will not only cause deformation of the connecting rod and crankshaft, or even break the crankshaft, but also incomplete combustion.
10. It is strictly forbidden to work while sick. .
11. Select a reasonable pair of cylinder liner and piston matching the engine operating conditions.

How to Overhaul the Wear of Marine Cylinder Liners
Cylinder liners are vulnerable spare parts. The inner surface of the upper part of the cylinder liner is an integral part of the combustion chamber, which is directly affected by the high temperature, high pressure and corrosion of the gas. The relative movement with the piston assembly makes it withstand side thrust and strong friction. The outer surface of the cylinder liner and the inner wall of the cylinder form a cooling effect. Water cavity, subject to cavitation and electrochemical corrosion.

The inner hole of the new cylinder liner has certain dimensional accuracy, geometric shape accuracy and roughness grade. The machining errors of general geometric shapes, such as roundness error and cylindricity error, should be within 0.0125~0.045mm, and the roughness should be within Ra0.4~Ra l.6um. After the cylinder liner is installed on the cylinder block, the geometric shape error increases, and the roundness error and cylindricity error should be controlled within 0.05mm. When the diesel engine is running, the reciprocating motion of the piston moving parts in the cylinder liner causes uneven wear on the inner surface of the cylinder liner, the wall thickness is reduced, and the roundness error and cylindricity error are greatly increased. Usually, when the wear amount of the cylinder liner exceeds (0.4%~0.8%) D (D is the cylinder diameter), the combustion chamber loses its sealing performance. Therefore, excessive wear of the cylinder liner will deteriorate its working performance, reduce the power of the diesel engine and cause damage to other parts.

The wear of the cylinder liner should be detected according to the requirements of the manual and the operation of the diesel engine, and the wear of the cylinder liner should be mastered and controlled to prevent excessive wear.
1. Wear measurement of inner surface of cylinder liner
At present, the wear conditions of the inner surface of the cylinder liner are all using general measuring tools, such as inner diameter micrometers, inner diameter dial indicators or random special inner diameter dial indicators. By measuring the cylinder diameter and calculating the roundness error, cylindricity error or inner diameter increment, the wear rate and comparing with the instructions or relevant standards, the judgment of whether it can continue to be used is finally made.

When measuring, the data of each measurement point should be recorded accurately, and the roundness of each cross section should be calculated according to this data and the maximum roundness should be calculated; Bore diameter increment; compared with the last measurement, the interval between the two measurements is determined so that the wear rate of the cylinder liner during this period of time can be calculated.
Compare the calculated maximum roundness, maximum cylindricity, or maximum inside diameter increment to instructions or standards to determine wear levels and repair options.

2. Maintenance of cylinder liner wear
When the cylinder liner is worn out, all indicators do not exceed the requirements of the instructions or standards, except that there are slight scratches or scratches on the inner surface of the cylinder liner, large grinding table and excessive wear, which can be repaired by maintenance personnel. The general method used is the boring repair method, that is, large pull marks, scratches and grinding tables are generated on the inner surface of the cylinder liner, or the roundness and cylindricity of the cylinder liner exceed the standard, but the inner diameter increment still meets the standard, use Machining (ie, boring) methods eliminate surface damage and geometric errors but the internal diameter increment after boring should still be within the standard.

For example, when the increase of the inner diameter of the cylinder liner exceeds the standard, the boring is carried out on the premise of ensuring the wall thickness and strength of the cylinder liner to eliminate the geometric error of the inner surface of the cylinder liner and the damage such as pull marks, scratches and grinding tables. The rear bore is equipped with a new piston assembly to restore the fit clearance between the cylinder liner and the piston.

After the cylinder liner is repaired, the running-in operation must be carried out before the normal operation of the installed machine, according to the requirements of the manual or depending on the repair condition.
The replacement time of the original and supporting factories of the medium-speed machine is generally 20,000 hours, the replacement time of high-quality professional products is 12,000-1,600 hours, and the counterfeit products are only 6,000 hours. When choosing cylinder liner products, we should pay more attention to quality in addition to comparing prices.