Causes and Treatments of the Engine's Piston Top Colliding with the Cylinder Head

First, damage to the connecting rod can cause the piston to hit the cylinder head. This kind of collision is an inertial collision and is not caused by the connecting rod or the piston being too long. Therefore, when the flywheel is being operated, it cannot be found that the piston touches the cylinder head. Only when the engine is running can it be heard (the sound increases with the increase of the speed, Low noise at low speed). But at this time, the connecting rods are often seriously damaged. This kind of inertial impact sound has been covered by the sound of the tiles.

Second, in the repair or assembly, inadvertently dropped a small screw, nut or screw into the intake pipe or piston (such as when inserting the injector, from the hole), or suction cylinder when inhaled, or small The gasket stuck to the underside of the cylinder head. When installing the cylinder cover, no attention was paid to staying in the mountain combustion chamber. After the vehicle was started, abnormal sound occurred and the piston top collided with the cylinder head.

3. After loosening the connecting rod bolts, it also causes piston inertia to hit the cylinder head. Select qualified bolts and tighten them as required. Old bolts must not be used.

Fourth, when the connecting rod cover is installed, the tile cover is reversed or mismounted with other connecting rod cover. Although the screws are tight, but the tile is still elliptical (connecting the rod body with the cap and processing, not to change the device), the inertia of the rotation causes the piston to hit the cylinder head, and a light and brittle, solid "click" sound will be heard. Does not weaken, cylinder head vibration. Therefore, special attention should be paid to this during maintenance.

Extensive reading:
To avoid cracks in the cylinder head:
1. When assembling, check whether each cooling water hole is open. Clean the cooling system regularly with alkaline solution to remove scale oil.
2. When the engine is working and the water tank is occasionally short of water, it shall not turn off immediately, but it shall slowly add water at low speed. Do not add cold water after the engine has gone hot. After parking, wait until the water temperature is below 40°C before releasing the water. Starting in the winter season can not add boiling water immediately, but should be heated water and add boiling water.
3. The tank should be filled with soft water, and change water as little as possible.
4. Diesel engines should avoid long-term work under overload.
5. The cylinder head bolts should be tightened evenly and the oil supply time should be adjusted correctly.