The camshaft: How it works, buying it and changing it in the vehicle

The camshaft is a central component of most diesel engines and petrol engines. Here, the component is responsible for the correct sequence of engine control. Fresh mixture can flow into the combustion chambers at the right time, while combustion residues are removed at the right time. If the camshaft is damaged, it must be replaced with a suitable spare part.

Construction and function of the camshaft

The camshaft plays a key role in the internal combustion engine. Here, the component opens the intake and exhaust valves at the right time and ensures optimum combustion. The camshaft is located in the cylinder head and connected to the crankshaft in the engine block by means of a timing chain, toothed belt or gearwheels. In this way, the rotary motion is transmitted to the camshaft, which rotates at half the speed of the crankshaft.

In order to be able to open each valve at the appropriate time, the shaft is equipped with cams corresponding to the number of valves. At the right moment and in the right sequence, the shaft presses against the valve and opens it. Depending on the vehicle, this process takes place directly, via hydraulic tappets, rocker arms or other components. The valves are closed by spring pressure. The shaft in the cylinder head thus determines the stroke and the opening times of the valves. Their proper functioning is important in order to be able to use the car as intended.

How the defect in the camshaft becomes noticeable

Camshafts are not wear parts, and often last as long as the car itself. In cars with high mileage or due to other influences, a problem with the camshaft can nevertheless occur in individual cases. The driver is most likely to notice a broken camshaft through symptoms such as poor power delivery or a rough and jerky engine running.

Increased fuel consumption can also be a sign of a defective camshaft. If the camshaft has run in or the cams of the shaft are worn, the timing is often no longer correct. However, the symptoms mentioned can also be caused by other defective engine components. Therefore, it is usually necessary to have the camshaft checked in the workshop.

Possible symptoms of a defective camshaft

• Engine power has noticeably decreased
• Engine running is out of round or engine bucks
• Rattling or nailing when accelerating
• Fuel consumption has increased
• Exhaust emissions have deteriorated

Reasons for defective cams and camshaft inspection

Various causes can lead to a defective camshaft. The main reason for a broken camshaft is still increased wear due to high mileage. If the car has been driven a lot, the engine and the camshaft have also been loaded accordingly. Since the camshaft has to open each valve against the force of the associated valve spring, material can wear off the cam over time.

The bearing shells of the camshaft can also be broken for various reasons, thereby also damaging the camshaft. A common reason for defective camshafts is a lack of oil or incorrect engine oil in the oil circuit. Since the oil is needed to lubricate and cool the bearings of the camshaft, a break in the oil film can quickly lead to damage. Skilled car mechanics can assess the condition of the camshaft after removing the valve cover. The bearing points can only be checked after removing the camshaft shells.

How professionals can change the camshaft

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Replacing a defective camshaft is complicated and requires advanced knowledge of engines. Only expert car mechanics can therefore change the shaft themselves. Depending on the manufacturer, model and engine variant, the procedure for changing the car parts can also differ. Regardless of the manufacturer, however, the valve cover is removed first in order to have free access to the shaft.

Depending on the engine and vehicle, it is then necessary to lock the camshaft axle with a special tool to enable removal. The camshaft sprocket is then removed, which sometimes requires the removal of the toothed-belt-cover. The belt itself must also be removed beforehand. Some engines also require the cylinders to be brought into a certain position beforehand.

Once the preliminary work has been done, the bearing covers of the shaft can be removed after loosening the screw fastening. Depending on the engine variant and manufacturer, it may be necessary to follow a certain sequence. The defective shaft can then be removed and replaced with a suitable spare part. The new parts are then installed in the reverse order. Some older engines still require adjustment of the valve clearance.

Three tips for changing the camshaft

1. Replace other components: If the camshaft is replaced, other components can easily be replaced as well. These include, for example, the camshaft sprocket, the timing chain or the timing belt. Valves and hydraulic tappets can also be replaced when the camshaft is removed.
2. Buy a camshaft set: In addition to the camshaft itself, a camshaft set contains other spare parts such as valves, hydraulic tappets or other valve control parts. The price for the camshaft set is usually cheaper than buying individual spare parts.
3. Change the oil: After installing the camshaft or camshaft set, it is a good idea to also change the engine oil. This way, the new shaft can do its job optimally. Oil and oil filter should always be changed at the same time, regardless of the vehicle.

Finding the right camshaft for your vehicle

If the camshaft in the car has to be replaced, it is important to only install exactly matching spare parts. In this way, the correct functioning of the engine and good engine running are guaranteed. At Autoparts24 you will find suitable original car parts for numerous vehicle models from different manufacturers. Thanks to the practical search function, it is easy to find suitable parts such as a camshaft or camshaft set for your car.

Compare prices of different shafts with cams

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All suitable OEM parts for your vehicle are clearly listed at Autoparts24.eu. The overview provides important information such as mileage, OE number, year of manufacture or price. This enables a convenient price comparison of used car parts at a glance.

Advantages of buying a used camshaft

If you buy an original camshaft used, you can often save a lot of money. When buying online, you decide for yourself which car parts meet your requirements and what price you end up paying. When you buy used camshafts from car recycling online, you not only save money, you also reduce the burden on the environment at the same time.