Updated at: 03-08-2022 - By: Lucas

The engine in your car is made up of numerous components, each with a specific function. It is possible for the piston and valves to contact, resulting in damage to the other and the engine itself.

The piston can be bent or slightly damaged if the valves hit it in a certain way. But first, let’s get a better understanding of what’s going on in each of these worlds.

Piston is a component of counter-pump engines and hydraulic chambers and gas compressors, among other similar appliances.

Using a connecting rod or piston rod, a vehicle’s engine transmits force from the container’s increasing gas to the crankshaft.

As an alternative, a valve is an engine component that regulates the flow of fluid in the engine by opening and closing or partially obstructing several pathways.

We can see a link between pistons and valves by looking at their definitions. Consequently, they may come into contact as a result of the process. What could be the reason for the piston striking the valves in most cases?

Numerous factors play a role, including

  • A bad timing belt
  • Failure of a tensioning device
  • A wrecked timing chain
  • A shattered timing gear
  • Anything significantly disrupting the introductory valve scheduling on a meddling engine.

Find out what could cause the piston to hit the valves by reading on. Investigate the specifics and learn about the warning indicators, the underlying causes, the immediate aftermath, and the final outcomes of the incident.

What Causes the Pistons to Hit the Valves?

Piston Damage From Valves

Disruption of the valve, whether intentional or accidental, is the most common reason of the piston striking the valve. The piston and valve will collide if the valve is interrupted while the piston is still working.

It is impossible for the two parts to come into contact since the piston pumps fluid while the valves allow it to flow.

When the piston rises, the valves also raise. Consequently, if the valves break, the piston will collide with them. In other words, everything that causes the valves to fail results in a collision between them and the piston.

The causes are numerous, but we’ll focus on four of them.

1. A Bad Timing Belt

It is the camshaft, which is driven by the timing belt, that controls when the valves open and close on the engine. As a result, if the timing belt tears or strips, the camshaft ceases to operate, which in turn impacts the valves.

Despite this, the crankshaft continues to turn. As long as it’s keeping the piston turning at its typical rate of 1000 revolutions per minute, everything is OK. As a result, the piston will slam into the sluggish valves.

2. Failed Tensioning Device

The timing belt is tightened by the tensioning device. If the timing device malfunctions, the timing belt loosens, causing the camshaft to be out of phase and causing the valves to open and close incorrectly. It is possible for the piston to strike the valves if the valves are unable to open or close.

3. A Wrecked Timing Chain

Due to the fact that the piston is still moving, it may come into contact with the bent valves as a result of a broken timing chain, resulting in engine damage. Insufficient compression prevents the machine from starting while the vehicle is not running.

4. A Shattered Timing Gear

A timing gear and a timing belt go hand in hand. To put it another way, a timing belt failure results in a collision between the piston and valve.

What Happens if a Valve Hits a Piston?

The valve may come into contact with the piston for a reason that can only be discovered during an engine diagnostic. Most of the time, the valves come to a halt at the dreaded dead end. A piston can withstand far greater pressure than a valve and still perform its purpose.

Valve bending and piston scratching are both possible outcomes. Engine failure is the result of this titanic struggle, and the only options are to replace the damaged valves and pistons or to replace the entire engine.

You’ll get a recommendation from your mechanic based on the amount of the damage.

What Happens to the Pistons After They Have Hit the Valves?

When the piston comes into contact with the valves, it suffers only minor damage. In most circumstances, the carbon buildup on the piston could be rubbed off by the accident.

In the event of an accident, the valves are damaged because they are never under pressure, whereas the piston simply suffers minor surface damage.

How can you Tell the Pistons are Hitting the Valves?

Piston Damage From Valves-3

It’s essential to learn more about automobiles. It lets you detect a problem before it gets out of hand by evaluating the car’s many indicators.

In order to avoid engine damage, you need to know what to look for when your car’s pistons start slamming against the valves.

The following are some of the most prevalent indicators that a car’s pistons are striking the valves.

  • The car will have very coarse idling
  • The engine will be choking
  • The vehicle will produce unusual sounds like rough rattling
  • The engine will lose power and will start to underperform.
  • When you check the heads of the piston, you might notice scratches, and they might be wet or spongy.

When Piston Hits the Valves, Does it Lead to Total Engine Failure?

The severity of the engine damage will be determined by the force of the hit. If discovered early, the valves may not have been significantly damaged or deformed.

This means that the engine won’t shut down completely, but you shouldn’t keep driving anyhow because doing so will just do more harm to the engine.

However, if the impact is great enough, the valves can bend and damage the cylinder, resulting in an engine failure.. In most cases, if the incident occurs while the vehicle is moving, this is the most common outcome.

When the timing belt jumps, the piston hits the valves, severely bending them and damaging the valve cylinder, which is caused by the crankshaft’s fast rotational speed.

Can this issue be repaired? Or a new Engine is Needed for Replacement?

In some cases, engine replacement is the only option for mechanical issues that cannot be remedied. The good news is that this issue can be fixed without having to replace the engine. Replacement valves are all that are needed when the valves are bent but the valve cylinder is unaffected.

It’s also possible that the piston was significantly damaged in the incident. As a result, it will also require replacement. In spite of this, pistons are rarely damaged and can be reused even if they have some wear on them.

After an accident, the engine of a car can develop additional very severe problems. Because of this, the engine will need to be replaced.

Rust can build up on engine parts owing to improper oiling, and when this happens, the portions affected first suffer from rust. As a result, the harm will be severe..

You have no idea how much this repair will cost unless you know how bad the damage is. As a result, valve repairs, which are required in over 90% of all accidents, may cost upwards of $1,000 in total.

Replacement of one valve head costs this much. As a result, the price will rise if the engine has other issues.


When a piston and valve collide, it’s common for the valves to be severely damaged. The timing belt failure is the root cause of the valve’s inability to open and close. This raises the likelihood of a collision with the piston, which is still running.

An engine’s valves may be destroyed, resulting in a total loss of power. However, if you pay attention to the vehicle’s signals, you can avoid serious injury.

As a result, it’s a good idea to familiarize yourself with the various indications and their meanings in order to avoid this and other mechanical issues that could endanger your safety as well as the safety of your car.