What are the causes of cylinder scoring?
1 Answers
Causes of cylinder scoring in automobiles include: 1. Insufficient piston ring clearance. If the end gap, side clearance, or back clearance of the piston rings is too small, the rings may seize due to thermal expansion during engine operation, pressing tightly against the cylinder wall or breaking, which can easily score grooves into the cylinder wall. 2. Piston pin protrusion. If the piston pin retaining clip is missing, dislodged, or broken, the piston pin may protrude during movement, easily damaging the inner cylinder wall and causing cylinder blow-by into the crankcase. 3. Improper piston-to-cylinder clearance. If the piston material is substandard, manufacturing dimensions are excessively inaccurate, or the piston deforms after piston pin installation, the clearance between the piston and cylinder may become too small. The piston can then seize due to thermal expansion, leading to cylinder wall scoring. 4. Severe carbon buildup on piston rings. Excessive carbon deposits can cause the piston rings to stick or seize in the ring grooves. Additionally, carbon acts as an abrasive, grinding longitudinal grooves into the cylinder wall. 5. Severe piston misalignment. Bent or twisted connecting rods, excessive parallelism or coaxiality deviations in the connecting rod journals, main journals, or piston pin seats can cause significant piston misalignment. This accelerates wear on the piston rings, piston, and cylinder wall, disrupting oil film formation.
