What are the manifestations and causes of engine cylinder scoring?

[VonIsabel]

Engine cylinder scoring manifests as follows: 1. In mild cases, cylinder compression pressure decreases, leading to loss of power; 2. Downward leakage of combustible mixture increases crankcase pressure, and severe cylinder scoring may cause crankcase explosion; 3. Upward leakage of lubricating oil into the cylinder causes oil burning; 4. Severe smoke emission from the exhaust pipe and abnormal engine noise; 5. Engine malfunction or even stalling. The causes of engine cylinder scoring are as follows: 1. Insufficient clearance between piston and cylinder: The clearance between piston and cylinder must strictly comply with the diesel engine manual specifications. Excessive clearance makes cold starting difficult, causes piston slap noise when cold, and reduces power. Insufficient clearance leads to cylinder scoring or seizure. 2. Insufficient piston ring end gap: When piston ring end gap or back clearance is too small, excessive friction between rings and cylinder wall, severe carbon deposits, or contamination during assembly with unclean fuel can cause scoring.