How Does Engine Piston Slap Occur?
4 Answers
Engine piston slap occurs due to the following reasons: 1. Bent or twisted engine connecting rod; 2. Excessive carbon deposits in the engine; 3. Poor engine lubrication conditions; 4. High cylinder pressure at high speeds. Solutions for engine piston slap: 1. If the knocking sound disappears after the car starts and the temperature rises, you can continue driving; 2. If the knocking sound persists and becomes more noticeable after the engine reaches normal temperature, the owner should stop and inspect the vehicle promptly to prevent traffic accidents; 3. After removing the cylinder head and extracting the piston, if severe cylinder ovality, scoring, or excessive clearance between the piston and cylinder is found, replacement is necessary—replace the cylinder liner, piston, and piston rings; 4. If the connecting rod is found to be deformed, it should be replaced as much as possible.
Last month while driving, my engine suddenly made that 'knocking' sound, which really startled me. After researching, I found out it's mainly due to abnormal fuel combustion in the engine, possibly because I used the wrong gasoline with too low octane, ignition timing being too early, or the engine overheating. An improperly set ignition advance angle can cause the fuel to explode prematurely in the cylinder, creating intense vibrations and producing that sound. Long-term issues like this can damage engine components, such as pistons and connecting rods. I later switched to higher-grade gasoline and had the cooling system checked to lower the engine bay temperature, which helped a lot. Remember, regular maintenance is key—don't ignore small problems.
Knocking issues are often encountered during car repairs, which are caused by engine fuel detonation. Common reasons include: the fuel's octane rating being too low, leading to overly rapid combustion; ignition timing being too advanced, causing early ignition during the compression stroke; or excessive carbon buildup in the cylinders, increasing the compression ratio and raising temperatures. These factors can cause the end gas to auto-ignite, creating pressure fluctuations that sound like knocking. The impact is significant, as it can easily damage piston rings and bearings. It's recommended to switch to higher-quality fuel, adjust the ignition timing, and clean out carbon deposits. Don't forget to check the cooling system, as insufficient coolant or a faulty fan can also raise temperatures and exacerbate the problem.
When I first started learning to drive, I heard a strange noise from the engine, somewhat resembling knocking. The instructor explained that it was caused by abnormal combustion of fuel in the cylinders. It could be due to using low-quality gasoline with insufficient octane rating, leading to premature ignition and knocking; or the engine overheating, such as from poor cooling or increased compression ratio. Simply put, it's the noise caused by flame propagation colliding with end gas. The first time I encountered it, I panicked and rushed to the 4S shop for repairs. Beginners should pay attention to regular engine maintenance and use the oil recommended by the manufacturer to reduce risks.
