Repair Method For Plane Deformation Of Cylinder Block And Cylinder Head

Due to the different deformation positions and degrees of the cylinder block and cylinder head, the repair methods of diesel generator sets are also different. The common methods are as follows.

① The bulge near the plane screw hole of the cylinder block can be smoothed with an oilstone or a fine file.

② The unevenness of cylinder block and cylinder head can be repaired by milling and grinding.

When the upper plane of the cylinder block is repaired by milling and grinding, the center line of the main bearing hole and the cylinder hole should always be taken as the processing and positioning reference. The upper plane of each cylinder block is allowed to be repaired for 2 times at most. The amount of repair each time should be less than 0.25mm, and the total amount of grinding should not exceed 0.50mm.

After the upper plane of the cylinder block is polished, check the height H of the cylinder block (that is, the distance from the center of the crankshaft main bearing hole to the upper plane of the cylinder block), and its value should be within the allowable range. Different engines have different values. Please read the instructions carefully when repairing.

At the same time, when the plane of the cylinder block is milled and ground, in order to maintain the normal clearance between the piston and the valve and the original compression ratio of the cylinder, the thickened cylinder gasket should be selected.

③ The unevenness of the cylinder block and the cylinder head can also be leveled with a blade, coated and ground, and the cylinder head is placed on the cylinder block and ground.

④ The warpage of the cylinder head can be corrected by knocking. First, place a steel pad with a thickness of about 4 times the deformation of the cylinder head between the cylinder head and the flat plate. Press the pressure plate on the middle of the cylinder head, tighten the bolts, make the plane in the middle of the cylinder head stick to the flat surface, and use a small hammer to knock three times along the cylinder head rib to reduce the internal stress generated during compression deformation. After staying for 5min, move the pressure plate to 1/3 of the total length and knock it, and then move it to 1/3 of the other end for pressure calibration and knock.

If the cylinder head is warped diagonally, the pressure plate should be pressed diagonally on the cylinder head. If the pressure calibration is excessive, it can be eliminated by placing the cylinder head next to the forge for a short time.

⑤ After the cylinder head plane is warped, it can also be trimmed by grinding.

After grinding the cylinder head, the thickness of the cylinder head will become thinner, the volume of the combustion chamber will become smaller, and the compression ratio will increase, which will cause the knock of the internal combustion engine. Therefore, when the thickness of the cylinder head is 2mm less than the standard thickness, the cylinder head should be replaced with a new one, or an additional cylinder gasket should be added to continue to use if the strength impact is small.

After the cylinder head is deformed and grinded, the combustion chamber volume is easy to be unequal, and the volume change difference should not be greater than 4% of the average value of each combustion chamber of the same internal combustion engine. For general internal combustion engines, the volume of combustion chamber shall not be less than 95% of the original factory, otherwise there will be a tendency of deflagration. Therefore, after the cylinder head is trimmed, the volume of the combustion chamber should be measured.

Thoroughly remove the carbon and dirt in the combustion chamber, place the milled cylinder head on the workbench to find the level, inject the measured diesel into the combustion chamber to be measured, stop pouring when the liquid level rises and just contacts the glass plate of the upper cover, and then observe the reduced volume of the measuring cup, which is the volume of the combustion chamber to be measured. After that, it shall be compared with the nominal volume of this type of combustion chamber. If it does not meet the volume, it shall be repaired

Jiangsu Starlight Electricity Equipments Co.,Ltd. has a young and professional technical backbone team, with an average working age of more than 10 years in the generator unit industry. There are 64 sales and service departments throughout the country to provide users with a one-stop service of machine room design, equipment supply, commissioning and maintenance at any time. No matter when and where, a well-trained service team will provide you with comprehensive and considerate protection. For more details, please contact us with sales@dieselgeneratortech.com.