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Camshaft: Function, Design & Types (Explained)

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Last Updated on: 7th September 2023, 12:38 am

The camshaft is a critical component of an internal combustion engine, it commands the flow of intake air and exhaust gases into and out of the engine.

This article will explore the design of the camshaft, its function, maintenance, and more.

engine camshaft

Design & Materials

Camshafts (also known as cams) are generally made from cast iron or billet steel, these materials known for their durability and resistance to wear during high stress operation.

The design of a camshaft is characterised by the placement and shape of lobes, which dictate when and for how long the engine’s valves open and close.

Types of Camshafts

There are primarily two types of camshafts:

  • Single Overhead Camshaft (SOHC)
  • Double Overhead Camshaft (DOHC).

SOHC designs have a single camshaft operating both the intake and exhaust valves, DOHC setups use two separate camshafts which can operate on different timing.

The choice between SOHC and DOHC largely impacts the engine’s power and efficiency.

SOHC vs DOHC camshaft

Function & Importance

The primary function of a camshaft is to control the engine’s valve timing, valves allow gases to enter into and leave the combustion chamber.

The intake valves control when the intake air enters the combustion chamber, while exhaust valves control when the exhaust gases leave.

Precise control of valve timing significantly affects engine performance, fuel efficiency, and emissions, which is why camshafts are so important.

Valve Timing and Its Importance

Valve timing refers to the precise moments at which the engine valves open and close during the engine cycle. Proper valve timing is essential to ensure optimal engine performance and fuel economy.

Interaction between Camshaft and Valves

The lobes on the camshaft interact directly with the engine’s valves.

As the camshaft rotates, these lobes open and close the valves at precise intervals, coordinating the flow of air and exhaust gases in and out of the engine.

Influence of Camshaft Design on Valve Timing

The shape, size, and placement of the camshaft lobes directly influence valve timing. A change in lobe design can alter the valve’s opening and closing times, significantly affecting engine performance.

parts of a camshaft

Signs of Failure & Damage

Symptoms of a failing camshaft might include loss of power, reduced fuel efficiency, or engine misfires. These can indicate that the camshaft is not accurately controlling valve timing.

Camshaft failure can stem from poor lubrication, excessive engine temperature, or manufacturing defects. Regular engine checks and maintenance can prevent these issues.

Regular oil changes, using high-quality engine oil, and timely engine checks are crucial for maintaining a healthy camshaft.

  • Andy Lewin

    Andy Lewin is a senior mechanic, ASE qualified master technician, and an experienced automotive engineer. He's passionate about serving the automotive community with the highest-quality and trustworthy information on all things automotive. He loves to write about car repairs, maintenance, car modifications and tuning, faults, and much more.

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