What Are the Causes of Piston Scuffing?

[LaNova]

Piston scuffing is fundamentally caused by the inability to form an oil film between the cylinder wall and the piston rings or piston, leading to poor lubrication or even dry friction. Piston scuffing refers to the appearance of noticeable longitudinal mechanical scratches and abrasions on the cylinder wall within the movement range of the piston rings. In severe cases, adhesive wear may occur, resulting in difficulties starting the engine or unexpected shutdowns. Below are preventive measures for piston scuffing: 1. For new engines or those after major overhauls, ensure proper running-in. This involves operating under good lubrication conditions, gradually increasing speed from low to high and load from small to large, strictly following the running-in procedures before putting the engine into full-load operation. 2. Correctly select the clearance between the piston skirt and cylinder liner, as well as the opening and side clearances of the piston rings, according to the manufacturer's specifications. Additionally, during repairs, ensure proper piston alignment and maintain the dimensional accuracy of the cylinder liner. 3. Maintain the coolant temperature within the normal range of 70°C to 95°C to prevent engine overheating. Preheating measures should be taken before starting the engine in winter. 4. Operate the engine properly—avoid overloading, unnecessary throttle blipping, and starting without sufficient coolant. 5. Regularly maintain the air filter to prevent dust from entering the cylinder. 6. Maintain the lubrication system properly to prevent mechanical impurities and carbon deposits from mixing with the engine oil, which can accelerate cylinder liner wear.