Cylinder head deformation will cause engine oil leakage, water leakage and air leakage, white smoke, blue smoke, backfire, difficult starting, power drop, fuel consumption increase, and abnormal noise increase.

1. Reasons for the deformation of the cylinder head
The tightening torque and method of the cylinder head bolts do not meet the specifications.

The cylinder liner is too much higher than the upper plane of the cylinder block, or the height of each cylinder liner is different, or the tightening torque of the cylinder head bolts is uneven, causing the cylinder head to warp and deform.

The surface of the cylinder block is uneven, causing the cylinder head to deform with the cylinder block after being heated.

The material of the cylinder head is unqualified, and the amount of deformation after heating is large.

2. Cylinder head deformation elimination method

The key to preventing cylinder head deformation is that the disassembly and assembly process when overhauling the engine must meet the specifications, and the second is to ensure that the engine's operating temperature is appropriate.

After the cylinder head plane is warped and deformed, the following methods are generally used to repair it.

Local preheating and pressure correction, combined with shovel to trim the plane. When the warping deformation of the cylinder head plane is greater than the specified value, the cylinder head can be placed on a special plate, and a shim iron with a thickness of about four times the deformation amount is placed between the two ends of the cylinder head plane and the plate, so that the middle of the cylinder head plane is suspended. . After combustion, tighten the bolts and preheat the middle of the cylinder head with a torch to make the temperature reach 300~400℃. Continue to pressurize to make the middle part fit the reference plane, hit the cylinder head reinforcement rib with a hammer 2 to 3 times, and let it stand for about 5 minutes. Move the pressure plate to the two ends of the cylinder head 1/3 of the full length, and knock them respectively. After standing for a period of time, loosen the pressing device and take out the cylinder head to check the correction situation. If it does not meet the technical requirements, it can be combined with shovel to trim the plane. The plane milling method can also be used. Place the cylinder head flat on the support frame, correct the level and tighten it, and then select the milling specification for milling.

The bulge near the bolt hole can be polished with oilstone, fine grinding wheel, or smoothed with a fine file.