Function of Camshaft in Engines: How It Works & Why It Matters

The camshaft in an engine regulates the opening and closing of the valves in the engine to ensure airflow and exhaust emissions. This is crucial since the performance of the engine and its efficiency largely depend on this process.

In this blog, you will learn the camshaft function in the engine, its types and when a camshaft fails to work.

What is the Function of the Camshaft in Engines?

The primary camshaft function in the engine in an internal combustion engine is to precisely control the opening and closing of the intake and exhaust valves. The key functions of the camshaft:

1. Regulation of Valves: As the camshaft rotates, cam lobes contact either lifters, rocker arms, or pushrods, causing the valves to open.

2. Control of Valve Lift: The size of the lobe determines the degree to which the valve opens; thus, determining the quantity of air-fuel mixture entering the cylinder.

3. Duration Control of Valves: The design of the cam lobe controls the period during which the valve will be open, hence influencing engine performance at various speeds.

4. Conversion of Motion: It acts to convert the rotational motion of the engine to the linear movement needed for valve operation.

5. Synchronisation with the Crankshaft: It runs at half the rate of the crankshaft; hence is usually synchronised with it via a timing belt or chain.

Without proper camshaft function, an engine cannot effectively breathe. Resulting in poor performance or, in many cases, total engine failure.

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How does a Camshaft Work?

The camshaft works by controlling the valve action within the cylinder. It is essentially a metal shaft with bumps on it, known as cams or lobes, which turn rotary motion into linear motion by pushing the valves.

Here are some key points that explain how a camshaft works in an engine:

1. Rotational Motion: The camshaft is rotated through the crankshaft that operates inside an engine.

2. Lobe Action: Due to the rotation of the camshaft, the lobes present on the shaft create pressure against lifters or pushrods.

3. Valve Opening: With such pressure exerted by the lobes, the intake valve or the exhaust valve gets pressed, thereby opening.

4. Valve Closing: After moving past the point where the lobe was present, there is a return movement of the valve due to a valve spring action.

5. Synchronisation: A camshaft rotates with the help of the engine’s crankshaft. It rotates at half the speed of the crankshaft in a four-stroke engine.

Why is the Camshaft Important in an Engine?

The camshaft is important in an engine because it controls the opening and closing of intake and exhaust valves at the correct time. This process ensures proper air flow, fuel combustion, and exhaust release, directly affecting engine power, fuel efficiency, and performance.

A properly functioning camshaft helps the engine run smoothly under different riding conditions, and without it, the engine may suffer from poor acceleration, reduced efficiency and unusual noises.

What are the Types of Camshafts?

The main types of camshafts include Hydraulic Flat-Tappet Camshaft, Hydraulic Roller Camshaft, Solid Roller Camshaft and more. Each of these has distinct features and functions in the engine.

To know more in detail about the camshaft types, read the pointers below:

Hydraulic Flat-Tappet Camshaft

This camshaft uses hydraulic lifters to automatically set the valve clearance, resulting in quieter engine running and reduced maintenance. Therefore, the hydraulic flat-tappet camshaft is preferred for normal street motorcycles and vehicles. Nevertheless, it may be less stable at high RPM levels.

Solid Flat-Tappet Camshaft

This camshaft is called a solid-lifter camshaft because it does not use hydraulic lifters but instead uses solid lifters. The camshaft design allows greater high-RPM stability and performance, making it ideal for race cars and other high-performance vehicles.

Hydraulic Roller Camshaft

In a hydraulic roller camshaft, there are roller lifters, which help to decrease friction between the lobes of the cam and the lifters. This system provides increased durability and higher efficiency because there can be more radical profiles on the cam.

Solid Roller Camshaft

Solid roller camshafts are made for high-performance and racing engines. They utilise roller lifters in conjunction with solid lifters for increased lift and radical timing. These types of camshafts can run at high RPMs effectively, although they need more care and are not very suitable for rideable motorcycles.

Single Overhead Camshaft

A Single Overhead Camshaft system utilises a single camshaft located in the cylinder head for controlling the movement of intake and exhaust valves. The SOHC engine is relatively simple, lighter, and economical in nature, thus widely used in commuter bikes.

Double Overhead Camshaft

A double overhead cam system contains two camshafts: one camshaft to actuate the intake valves and another camshaft to actuate the exhaust valves. The main advantage of a DOHC engine is that it produces good airflow, high speed, and efficient fuel combustion.

Also Read: Crankshaft: Types, Stress, and Deflections

When Do Camshafts Fail to Work?

Camshafts typically fail due to inadequate lubrication, worn lifters, improper break-in, or mechanical interference. These issues often come from poor maintenance or contaminated oil.

Here are the key reasons for camshaft failure:

1. Insufficient lubrication is the number one cause, leading to rapid lobe wear and bearing failure. Dirty or degraded oil acts like an abrasive, destroying polished surfaces.

2. Sticking or damaged lifters or tappets create uneven pressure, wearing down the cam lobes, particularly during the break-in process of a new camshaft.

3. Failing to use a proper break-in oil or failing to use new lifters with a new camshaft can lead to premature failure.

4. Broken timing chains, snapped timing belts or seized cam phasers can cause the camshaft to fail or operate improperly. 

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How to Maintain Camshafts?

To maintain camshafts, ensure proper lubrication, replace lifters simultaneously and monitor valve lash. If you maintain the camshaft by keeping these factors in mind, it can last longer. Here are some of the tips to maintain camshafts properly:

1. Regular Oil Changes: Use good-quality oil and change it at the prescribed intervals to avoid the formation of sludge.

2. Lubricate Adequately: Camshafts should be oil splashed. It’s important to check that the oil pressure is maintained and that proper viscosity oil is used.

3. Proper Break-in: When fitting a new camshaft, apply zinc-lubricant and break it in with the engine running at 1,500 to 3,000 RPM for 20 to 30 minutes to harden the lobes.

4. Replace Lifters Together: Always change lifters (tappets) at the same time as camshaft installation. Old lifters will damage the new camshaft.

5. Valve Lash Adjustment: Adjust valve lash regularly to reduce undue pressure on camshaft lobes.

6. Check Timing System: Check timing chain, gear, or belt to avoid erratic operation of the camshaft.

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What are the Advantages and Disadvantages of a Camshaft in an Engine?

Advantages of a camshaft include ensuring efficient performance by regulating valves' opening and closing times, thereby enhancing fuel economy and power production. Despite being robust, the camshaft also has several downsides, such as mechanical complexity, wear and tear, and repair expenses.

Advantages

1. Regulates the precise timing of valve opening and closing, ensuring the four-stroke process is efficient.

2. Higher lobe lift enables more air and fuel mixture to enter the engine cylinder, thus improving performance.

3. Camshafts are designed for different purposes by modifying them through grinding processes to accommodate various needs, from high-speed racing engines to fuel-efficient vehicles.

Disadvantages

1. Continuous friction between the cam lobes and the valve parts demands continuous lubrication, and the parts can become worn out over time, potentially resulting in engine breakdowns.

2. The timing setup is intricate and requires precise alignment. A bad camshaft can cause poor performance, engine noise and misfires.

3. High-performance camshafts can sacrifice low-RPM torque for high-RPM power. This affects driving comfort in daily driving.

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Final Words

Understanding the camshaft function in the engine is important for maintaining smooth motorcycle performance, fuel efficiency, and engine durability. Learning how a camshaft works and understanding its types and proper maintenance can prevent costly repairs and performance issues.

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Frequently Asked Questions

What is the difference between a camshaft vs crankshaft bike?

The camshaft controls the opening and closing of engine valves, while the crankshaft converts piston movement into rotational motion. Both components work together to ensure proper engine timing and smooth motorcycle performance.

Can a car run without a camshaft?

No, a vehicle cannot run without a camshaft. It is because the intake and exhaust valves will not open and close correctly. This prevents the combustion process that is required for engine operation.

What is the lifespan of a camshaft?

A camshaft can last for many years, if maintained properly with regular oil changes, correct lubrication and timely screening. Poor maintenance and contaminated oil can significantly reduce its lifespan.

Is the camshaft repairable?

Yes, minor camshaft damage can sometimes be repaired through regrinding and polishing. However, severely damaged camshafts usually require complete replacement to maintain proper engine performance.

What is a camshaft in a bike engine?

A camshaft in a bike engine is a rotating shaft with lobes that control the opening and closing of intake and exhaust valves. It ensures smooth combustion and engine efficiency.

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