What are the hazards of engine knocking?

[McJoy]

Engine knocking mainly has the following hazards: 1. Decreased engine power, increased temperature, increased load and wear on internal engine components, and increased formation of carbon deposits inside the engine. 2. Internal engine components deform due to increased temperature, and the amount of heat carried away by the coolant increases. The following are the causes of knocking: 1. During the compression stroke of the engine piston, the engine ignites and explodes before the piston reaches the top dead center. 2. The quality of the fuel is too low to meet the required compression ratio inside the cylinder, causing the fuel to self-ignite and explode before the piston reaches the top dead center of the stroke.

[VonStella]

When test-driving Lao Wang's modified car the other day, I heard a 'knock knock' detonation sound as soon as I stepped on the gas. This engine knocking is no trivial matter—it can make your engine components retire early. Specifically, those abnormal combustion shockwaves repeatedly hammer the piston crown. Over time, the piston rings may deform and leak, and the cylinder walls could get scratched. Even worse, the connecting rod bearings can get shaken loose—my friend's car needed a complete overhaul kit last time because of this. Detonation also generates abnormal high temperatures that can burn the valve edges and easily clog the catalytic converter. These component failures aren't fixable with just a few hundred bucks—you might end up needing a full engine rebuild.

[NoahAnn]

The biggest fear when driving is encountering engine knock, which is like installing a time bomb in the engine. Each vibration creates shockwaves in the cylinder, loosening the piston pin and easily wearing out the crankshaft bearing. I've seen many cars where the piston crown was directly burned through by high temperatures due to prolonged knocking. Knocking also disrupts the normal combustion rhythm, wasting fuel and increasing fuel consumption by up to 20%. Even more dangerous, the shockwaves can cause the spark plug ceramic to shatter, with fragments falling into the cylinder and scratching the cylinder walls. If this happens at high speed and suddenly causes loss of power, the consequences are unimaginable. In short, knocking issues should not be delayed; any unusual noise should prompt an immediate check.

[SkylarFitz]

Engine knocking is far more harmful than just noise. It generates impacts three times stronger than normal combustion, directly damaging the engine's core components. These violent vibrations accelerate crankshaft wear, causing connecting rods to deform or even fracture. High temperatures can also lead to exhaust valve erosion, and increased valve clearance results in noticeable power loss. Prolonged knocking may create hot spots on piston crowns, triggering a vicious cycle of pre-ignition. During my last maintenance, the mechanic pointed to carbon deposits on the cylinder head and told me these were scars left by knocking. The worst-case scenario is cylinder head gasket failure, allowing coolant to mix with engine oil, which can completely destroy the engine.

[McLydia]

My old car suffered from engine knock last year. At first, there was just a metallic knocking sound during acceleration, but the problem gradually worsened. The shockwaves from knocking can deform piston rings, leading to blue smoke from burning oil. The crankshaft position sensor also got damaged, causing the check engine light to come on intermittently. The most annoying part was the unstable engine operation - the RPM would fluctuate unpredictably at red lights. When the mechanic opened up the engine, we found cracks on the piston skirts and severe wear on the connecting rod small ends. This issue also affects emissions, and the car almost failed its annual inspection. The repair cost several thousand yuan - I should have addressed the abnormal noise earlier.