How the camshaft knocks: why this happens, what to do

Hi all! Any extraneous knocks or sounds when the car is operating should alert the driver. Regardless of the nature and origin, there should not be any unnecessary sounds during normal operation of the machine. Today I propose to talk about how the camshaft knocks, whether it can knock, why this happens and what to do in this situation.

The job of the camshaft or simply the camshaft is to control the opening and closing of the internal combustion engine valves. With its help, engine strokes are synchronized. As you know, valve knocking is also possible. We have already talked about them.

You should find out why such symptoms occur, what actions the car owner needs to take, and what consequences you should be prepared for if you do nothing.

A little about the camshaft

Fortunately for many, the camshaft is not one of the components that are positioned as capricious, often and quickly failing. The resource largely depends on the quality of the part and operating conditions.

The camshaft has a life limit. Uninterrupted operation can last from 50 to 150 thousand kilometers. These are fairly average indicators, since each situation is still individual. Active work is already underway to remove this element from the engine design. Moreover, experts say that in the future the camshaft may completely cease to be part of the engine. It will be replaced by electromagnetic actuators.

It is difficult to say how effective and realistic this will be in the near future. Plus, some skeptics doubt the correctness of the transition from a mechanical part to a computer-controlled actuator.

Camshaft knocking: what to do

If the camshaft starts knocking on a car, the driver should prepare for considerable expenses.
At the same time, it is far from certain that we are talking about replacing the camshaft, since faulty hydraulic compensators or bearings can also lead to knocking. Based on this, we can conclude that if you suspect a knock in the camshaft, you should send the car for diagnostics as quickly as possible. It is possible that it will reveal not only problems in the units responsible for synchronizing engine cycles, but also in other elements. It is important to note that by delaying diagnostics, the driver greatly risks increasing the cost of repairs. If hydraulic compensators begin to fail, they can cause the camshaft to malfunction. Based on this, the sooner the diagnosis is carried out and the cause of the camshaft knocking is determined, the less likely it is that it will fail.

Cars that are not equipped with hydraulic compensators can drive with a knocking noise coming from the camshaft for more than 50 thousand kilometers, but after that the engine may need to be completely replaced or overhauled.

Can the camshaft make a knocking noise?

Many people have encountered crankshaft knocking in their lifetime. But not all drivers know how and when exactly the camshaft knocks.

It's all about the sounds. They are really very similar to each other. This appears the same on different cars:

for VAZ 2106;
Niva has 8 valves;
VAZ 2107;
VAZ 2109;
on Priora;
VAZ 2110;
VAZ 2114;
for Daewoo Nexia;
for Subaru Forester, etc.

But what should a car owner do when he hears a sound, but cannot understand what exactly is knocking? Is it the crankshaft or the camshaft?!

Here you just need to listen and observe the behavior of the car and specifically the engine. Sometimes this makes it quickly clear where the source of extraneous sound is, and which unit needs to be prepared for repair.

The key role is played by the fact whether you hear sounds when it is cold or when it is hot.

You will be able to hear sounds from the camshaft only when the internal combustion engine is cold, when the engine starts and the lubricant has had time to leave the rubbing elements. After starting, the oil will gradually lubricate them, causing the knocking noise to disappear.

The camshaft makes so-called dull sounds;
Noises appear precisely when the engine is cold, when the engine starts;
Initially the crankshaft sounds similar;
As it gains speed, the faulty crankshaft acquires a louder sound;
In fact, the camshaft is dull and the crankshaft is sonorous;
An increase in speed will help to accurately determine;
If you still can’t identify it by sound, you will have to carry out diagnostics.

Based on these points, you will be able to independently diagnose the nature and source of the malfunction without any problems, and then begin the appropriate actions to eliminate them.

The camshaft is knocking: what to do?

Hello, dear motorists! Who didn't study physics at school? Raise a hand. That's right, there are none. They studied everything, but not everything; for some reason they put the acquired knowledge into practice. What was it? This was a prelude to answering the question: why does a knock appear when the engine is cold, but as soon as it warms up, the knock disappears. The property of metal parts is triggered - expansion when heated.

Your engine, which is no longer new, has worn out certain engine parts: the pistons are knocking with their skirts, the crankshaft in the liners, the chain, the camshaft is knocking in the bed or with cams.

In principle, the “terrible” has not yet arrived, but it’s time to think about engine diagnostics. So we will try to consider such an important part of the engine as the camshaft, and more specifically, the knock of the camshaft.

If you hear a dull knock when starting a cold engine, you should understand that it is the camshaft knocking. The knock of a camshaft differs from a knock, for example, of a crankshaft, in that the sound of the crankshaft becomes louder as the speed increases.

Once the oil reaches the bearings, the camshaft knocking stops. It's too early to panic. If you have valves in the cylinder head without hydraulic compensators, then the “capital” has a period of 50,000 km. Naturally, there is no need to delay.

Better yet, as soon as you hear that the camshaft is knocking, start diagnosing and repairing the engine. Camshaft repairs performed in the initial stage of the “disease” will save you from expenses and more extensive engine repairs in the future.

During diagnostics, by the way, you can take advantage of the situation and, if you have already thought about it, then replace the camshaft. There is probably no point in explaining to you that a sports camshaft will significantly increase engine power. But this must be a conscious decision.

Traditional causes of camshaft knocking

The reasons why the camshaft knocks can be very diverse. We will present for your consideration the most characteristic ones.

cam wear. As the camshaft cams wear out, knocking will appear not only when starting a cold engine, but also when starting a warm engine, or when running a cold one.
Fuel supply adjustment is broken. Everyone is familiar with the expression “tapping fingers.” This happens with early ignition. The so-called detonation combustion of fuel occurs, and hence the knocking of the fingers;
camshaft bed malfunction;
camshaft deformation (axial runout);
mechanical damage to the camshaft, for example, a broken journal or a burst camshaft support;
oil. This is a separate topic for discussion. But, in short, any deviation in the engine lubrication system leads to malfunctions. Including the camshaft. Poor quality oil, mechanical impurities getting into the oil, fuel or coolant getting into the oil;
and engine operation without oil (no comment).

My engine knocked, what should I do?

If you have a knocking sound in your engine. The first, and not unreasonable, action of the driver is to conduct a comprehensive engine diagnostics. Early diagnosis and timely repair are definitely better than eliminating the consequences that could cover the engine with an avalanche.

What to do

Drivers had to deal with the fact that occasionally after the start an incomprehensible knocking sound began to appear, but when accelerating and warming up the engine it disappeared. As we have already figured out, most likely the camshaft on the engine has failed.

Now another question. What to do in such a situation? If it is the camshaft that starts knocking, you should be prepared to spend a considerable amount of money. But this is not a 100% probability, since sometimes hydraulic compensators begin to knock, or knocking noises are made by worn gears and bearings. Not all situations solve the problem by replacing the entire camshaft. If you suspect a knocking noise from this unit, it is better to immediately go for diagnostics. Due diligence can help you find out where the source of the problem is and what needs to be done about it.

It’s definitely not worth delaying diagnostics. If the compensators fail, and the problem was in them, then the chain reaction will lead to the breakdown of the shaft itself. And these are completely different expenses. So it would definitely be a good idea to check the hydraulic compensators.

You can drive a car without hydraulic compensators with a knock from the camshaft for more than 50 thousand km, but then you will probably have to completely change the engine or carry out major repairs.

As you can see, delaying the check is definitely not in your interests.

Elimination methods

Basically, the appearance of a knock in the camshaft promises the driver considerable expenses and unnecessary headaches. The repair procedure is not always limited to the usual replacement of the camshaft; sometimes the appearance of a knock in it can be a consequence of the failure of hydraulic compensators and bearings. In any case, at the first symptoms of a violation, the faulty vehicle must be sent for diagnostics to a specialized service center. Perhaps professionals will be able to find violations not only in the unit itself, but also in its other components. It is extremely unwise to delay diagnostics in this turn of events. This can lead to costly repairs in the future.

Causes of camshaft knocking

The appearance of a characteristic knock can be caused by many reasons. Since the camshaft includes many other parts, it is likely that a problem with one of them could affect the operation of the entire system. If knocking is heard strongly, the following factors may be the source of the problem:

Problems with the camshaft bed;
Violation in the lubrication system;
Mechanical damage or deformation of the camshaft;
Failure to regulate the fuel supply to the system;
The resource of the cams has been exhausted.

In most of these situations, it is quite difficult to cope with the problem on your own. Ill-proper repairs can lead to a worsening situation and serious problems.

The video will talk about troubleshooting the camshaft:

Published: February 28, 2018

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Play in the shaft bed. It is unlikely that you will be able to solve the problem on your own. This requires boring or honing of the bed itself, or a complete replacement of the unit;
Problems in the lubrication system. Even with a slight disruption of its operation, sound may appear. Moreover, the reason is not only in the quantity, but also in the quality of the lubricant;
Deformation and mechanical damage. Most often, the supports burst and the neck breaks;
Violations in the regulation of fuel supply processes;
Development of the resource of cams. If the problem is definitely in the camshaft, and the knocking noise appears even when it’s hot, then the problem is in the cams.

It is almost impossible to give an accurate forecast as to what exactly was the source of the knocking noises without conducting comprehensive diagnostics. Masters often talk about this in various videos where the problem under consideration is described.

In any case, the knock should alert you. Whether you have hydraulic compensators or not, it does not matter. The sooner you send your car for diagnostics, the higher the chances of getting by with little damage and spending a minimum of effort and money to fix the problem. All in your hands.

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Why is the camshaft knocking?

The camshaft of a car consists of a number of elements, and the malfunction of most of them leads to the appearance of a characteristic knocking sound during operation of the car engine. If you hear the camshaft knocking, you can assume one of the following reasons:

Problems with the camshaft bed. In such a situation, independent repair is impossible. It will be necessary to boring or honing the camshaft bed or completely change the part;
Lubrication system malfunction. Even a small deviation from the norm in the lubrication system can cause the camshaft to start knocking. In this case, the reason may be associated not only with the small amount of incoming oil, but also with its quality. If, as it passes through the units, coolant or other impurities enter the oil, it begins to cope with its tasks worse;
Deformation of the camshaft or mechanical damage to it (its parts). The most common problems include broken camshaft bearings and broken journals;
The fuel supply process adjustments are violated;
The life of the cams has been exhausted. This malfunction can be diagnosed if you are sure that the camshaft is knocking. If it continues to knock while the engine is running hot, then the problem is with worn cams.

The above are just some of the problems that can lead to camshaft knocking. The sooner a specific malfunction is identified using diagnostic equipment or visual inspection by specialists, the greater the chance of eliminating the problem before it begins to affect other elements of the unit.

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