What Does Cylinder Scoring Mean?
2 Answers
Cylinder scoring refers to the formation of deep grooves on the inner wall of the cylinder, causing the piston, piston rings, and cylinder wall to lose their sealing ability during friction. This results in reduced cylinder compression pressure and loss of power, making it one of the common faults in automotive engines. The following are the causes of cylinder scoring: 1. The clearance between the piston and cylinder is too small. 2. The fit between the cylinder sleeve outer diameter and the bore is either too tight or too loose; the cylinder sleeve quality does not meet requirements; or the cylinder sleeve hardness is too low, leading to piston scoring. 3. The piston itself does not meet quality requirements, or the piston pin and piston pin bore assembly are too tight, causing axial deformation of the piston, resulting in the piston skirt roundness not meeting specifications. 4. During assembly, the piston and cylinder were not thoroughly cleaned, leaving sand particles trapped in the piston or its ring grooves, or the intake passages were not cleaned properly. 5. The air filter is faulty or was not installed during testing. 6. The lubricating oil is of poor quality, contains excessive impurities, or does not meet the required specifications. 7. The piston rings are broken or the piston ring end gap is too small.
Cylinder scoring means there's a problem inside the engine, where the piston scratches the cylinder wall during movement. Sounds scary, right? There are many causes, the most common being insufficient lubrication, delayed oil changes with degraded oil, or engine overheating. The symptoms are quite obvious too - the car makes strange creaking noises when driving, has noticeably weaker acceleration, and fuel consumption is significantly higher than usual. In severe cases, the engine may even smoke or stall. I've experienced this firsthand - a friend's car used cheap low-grade oil to save money, resulting in cylinder scoring repairs costing tens of thousands. So don't be careless when driving, especially check the oil and cooling system before long trips. Maintaining normal operating temperature can effectively prevent this trouble.
