Camshaft vs. crankshaft: How they work and their differences

In a car engine, many components work together to produce power. Two such important parts are the camshaft and crankshaft. While the sounds of these two are nearly identical, they have very different functions. One regulates the opening and closing of the valves, while the other converts the motion of the pistons into rotational motion. Without either of them, the engine will not even start. That is why understanding how these parts work is important for maintaining your car properly and avoiding expensive repairs.

In this blog, let us get to know more about camshaft and crankshaft and the difference between camshaft and crankshaft.

What is camshaft?

A camshaft is an extended metal rod with egg-shaped lobes called cams. These lobes press on valve lifters or rocker arms to open and close the intake and exhaust valves of the car's engine at the right time. It rotates slowly, normally at half the speed of the crankshaft, which is controlled by a timing belt or chain. The camshaft decides when the engine takes in air and fuel and when it pushes out exhaust gases. As a result, the camshaft dictates engine timing, power delivery, smoothness and overall efficiency.

What is crankshaft?

The crankshaft is a durable, heavy-metal shaft located at the lower section of the engine, featuring offset crankpin journals. It is linked to the pistons through connecting rods.

As the pistons move up and down during combustion, this motion is converted into rotational movement by the crankshaft. That rotational force is then transmitted to the gearbox, ultimately driving the wheels. The crankshaft must remain perfectly balanced at all times to prevent vibration, where bearings and engine oil play an important role in its smooth rotation. Without a functional crankshaft, the engine cannot transfer power and the car cannot move.

How a camshaft works

The camshaft operates in a very precise, rhythmic pattern. Its main job is to control when the valves open and close so the engine breathes correctly. Here’s how it works:

• The timing belt or chain rotates the camshaft and keeps its movement perfectly synchronised with the crankshaft.
• Cam lobes press on lifters or rocker arms to open intake valves.
• The air-fuel mixture enters the combustion chamber.
• Other cam lobes open the exhaust valves to allow the burnt gases to escape.
• Valve springs assist in closing the valves once the lobes have passed.

How a crankshaft works

The crankshaft converts straight piston motion to rotational motion. The process, though simple, is important. Here's how:

• Fuel ignites inside the cylinder and forces the piston downward.
• The connecting rod transfers this force to the crankshaft.
• Its offset journals cause the crankshaft to turn.
• This turning motion drives the flywheel.
• The flywheel sends the power to the transmission.
• Transmission sends power to the wheels.
• Balanced crankshaft rotation ensures low vibration and stable engine RPM.

Key differences between camshaft and crankshaft

The table below explains camshaft vs crankshaft in detail:

Which is more important: Camshaft or Crankshaft?

Neither component can function effectively without the other. The crankshaft acts as the engine’s heart, creating rotational power that drives the vehicle. The camshaft functions like the engine’s brain, controlling the precise timing of valve operation. Without the camshaft, the engine cannot take in air or release exhaust properly and without the crankshaft, there would be no motion at all. Rather than one being more crucial, both work together and the engine relies on their coordination to operate smoothly.

Common problems associated with camshafts and crankshafts

Without proper maintenance, both the camshaft and crankshaft eventually wear out. The following are the typical issues you may look for:

• Worn cam lobes due to low-quality or badly lubricated oil.
• Incorrect valve timing due to a broken timing belt or chain.
• Damaged rocker arms or lifters that can cause noise and misfires.
• Crankshaft wearing that leads to knocking sounds.
• Crankshaft bent or cracked because of extreme heat or stress.
• Failure of the connecting rod may cause serious damage to the crankshaft.
• Low oil pressure, affecting both shafts, leading to rapid wear.

Impact on vehicle performance and engine efficiency

A well-maintained camshaft ensures proper valve timing, improving combustion and fuel efficiency, resulting in better power delivery. Once there is a timing error, it gives the impression of a weak, hoarse or noisy engine. A well-balanced crankshaft ensures smooth rotation, stable RPM and reduced vibration.

When the crankshaft is in bad condition, the engine loses its power, shakes and becomes more fuel-consuming. Together, these two components decide how smoothly the engine runs.

Why understanding engine components matters for car insurance

Understanding some basic engine components helps with car maintenance, preventing accidental breakdowns that could result in unsafe on-road situations. Though normal wear and tear of the mechanical parts is generally not covered by insurance, knowing such components helps in assessing when repairs are needed, maintaining service records and avoiding disputes at the time of car insurance online claims. Proper maintenance reduces the chances of a breakdown on the roadside, keeps your car safer to drive and may even indirectly help you in avoiding situations leading to insurance claims.

Conclusion

The camshaft and crankshaft are two of the most vital engine components that work together to keep your car running. One regulates the intake of the engine while the other converts energy from combustion into motion. Knowing the camshaft and crankshaft difference in how they work not only makes you an educated car owner but also can help you identify signs that might require expensive repairs.

While maintenance protects the engine mechanically, having proper third-party car insurance ensures legal compliance on the road.

FAQs

1. What materials are camshafts and crankshafts made from

Camshafts are typically cast iron or billet steel, while crankshafts are forged or cast steel for strength and heat resistance.

2. What role do sensors play in camshaft and crankshaft operation?

Camshaft and crankshaft sensors monitor position and timing, enabling the ECU to control ignition and fuel injection accurately.

3. How does poor lubrication affect these components?

Insufficient lubrication causes increased wear, overheating and potential damage to cam lobes, bearings and journals.

4. Do diesel and petrol engines differ in these components?

Diesel engines use larger crankshafts and different cam profiles to handle higher compression and distinct combustion characteristics.

Disclaimer: The information provided in this blog is for educational and informational purposes only. It may contain outdated data and information regarding the topic featured in the article. It is advised to verify the currency and relevance of the data and information before taking any major steps. ICICI Lombard is not liable for any inaccuracies or consequences resulting from the use of this outdated information.

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