While the term “engine knocking” refers to the knocking sound the engine makes, the usage of the term is quite conflicted. It’s used for different types of “knocking” that occur in the engine.
One type of knocking occurs when you try to accelerate after slowing down, without down-shifting a gear. In this case, instead of a smooth pick up, the engine will react as if it is grasping for breath, making it jerky, with a metallic “knocking” sound. This phenomenon of engine knocking is usually mistaken for engine grasping.
While another type of knocking known as “pinging”, refers to the internal combustion or ‘detonation’ of the air/fuel mixture in the cylinder that does not start off correctly. This is in response to ignition by the spark plug, but pockets of air/fuel mixture tend to explode outside the envelope of the normal combustion front.
Causes of Engine Knocking
There are many different causes of engine pinging:
- Low fuel octane reading and poor fuel quality
- High compression
- Overheating of the engine
- Knock detector being faulty
- Blocked exhaust, giving high backpressure
Prevention of Engine Knocking
The first type of engine knocking is simple to amend. Nonetheless, both types of knocking tend to fade away with increasing revolutions if you change down again to regain uniformity in performance. However, engine pinging, if not attended to, can cause damages that may be irreparable. There are some ways you can adapt to avoid this technical problem:
- Using appropriate octane-reading petrol for the engine
- Warming up the engine when first starting so it does not stress before getting primed, especially during winters
- Avoiding long rides without breaks, since overheated engines tend to knock
- Lowering engine compression