Crankshaft vs Camshaft: The Definite Guide

Want to know about the Difference between Crankshaft and Camshaft? You’ve landed in the right place.

Check it out below.

What Is A Crankshaft?

Crankshaft vs Camshaft
The Crankshaft converts the power from the up and down motion of the pistons to rotating power to move your vehicle.

The Crankshaft or crank converts the power from the up and down motion of the pistons to rotating power to move your vehicle. The pistons are attached to the crankshaft. They create compression inside the cylinders when fuel is injected and then ignited. The power created in the cylinders by the pistons causes the cylinder to rotate the crankshaft. This in turns provides the power to make your vehicle run. When everything runs smoothly you get the performance your engine was designed to produce. Manufacturers use a sophisticated system of sensors to monitor engine functions.

Sensors send an electronic signal to the onboard computer, sometimes called an ECM, Electronic Control Module. This is where the data is analyzed and responds to that data to determine what the engine must do in order to continue to perform as it was designed to do.

What Is A Camshaft?

Crankshaft vs Camshaft have different structures, roles and functions, but they work together to make the car engine running
The crankshaft transfers the power created in the cylinders to rotational power to provide torque to the engine.

The Camshaft is a straight, usually steel, rod with small oval-shaped camshaft lobes that allow the spring-loaded valves on the top of each cylinder to open and close. Spring-loaded means the valves are designed to remain in the closed position until the camshaft lobe opens the valve by pushing down on it. The camshaft is designed in such a way that it synchronizes with the rotation of the crankshaft to provide power. Engine manufacturers design engines with two different configurations, single overhead camshaft SOHC or dual overhead camshaft DOHC. Most, if not all vehicles today use either.

In the past, there was a third option, the camshaft, and pushrod configuration. Today, engines are so sophisticated and fuel-efficient that the camshaft and pushrod configuration might only be found in specialized engines. This article will focus on the overhead camshaft configuration.

What Does A Camshaft Do?

The camshaft allows the correct valves to open and close at the correct time in each cylinder. This function is known as the firing order. The camshaft controls the firing order. There is only one correct sequence in the firing order of the cylinders in order for the engine to provide the torque to the crankshaft which is used to power the transmission.

A camshaft works in conjunction with the crankshaft to make sure the cylinders fire in one specific order only based on the engine specification. On the intake stroke, it opens the intake valve to allow fuel and air to enter the cylinder. It closes both the intake and exhaust valves on the compression and power strokes then opens the exhaust valve on the exhaust stroke. Although diesel engines do not have spark plugs, the camshaft performs the same function, which is to open and close valves to provide power. The internal combustion engine has come a long way from the old 20th-century engine that was made from steel and iron. The camshaft and pushrod configuration periodically needed a valve adjustment to ensure the proper valve clearance. The engines did not have the tight tolerances they have today. Aluminum, better grades of steel and other materials help the camshaft and crankshaft proved a smooth fuel-efficient ride.

What Does A Crankshaft Do?

The crankshaft transfers the power created in the cylinders to rotational power to provide torque to the engine. The power created in the cylinders then pushes the piston down which turns the crankshaft that provides the forces necessary for the transmission to operate. It works simultaneously with the cam. The crankshaft uses a timing chain attached to the camshaft on the top of the engine which provides power.

Here is a brief analogy. The crankshaft might be similar to a heart and the camshaft similar to the muscles which allow the heart valves to open and close so blood can flow. Both must operate correctly for your anatomy in order to maintain health.

If the camshaft is damaged it’s likely the vehicle will only operate for a limited time but the vehicle will run poorly, if at all. On the other hand, if the crankshaft is damaged, it’s very likely the engine will have to be replaced. If the engine cannot provide torque to drive the transmission, it will not move. This illustration shows a basic engine with dual overhead cams on the top and the crankshaft on the bottom. Notice that the diameter of the camshaft is much smaller than the crank. The camshaft is not as robust as the crankshaft because the camshaft operates delicate valves. The crankshaft operates from the power of huge pistons.

The Different of Crankshaft Vs Camshaft

Camshaft vs Crankshaft
Crankshaft and camshaft work together to power the car engine.

The camshaft and the crankshaft work together to power the engine. The camshaft operates the values which allow the piston to force the crankshaft to turn which provides power to the transmission. A timing chain would attach the crankshaft to the camshaft at the front of the engine.

CrankshaftCamshaft
Rod with specific indentures attached to pistonsStraight rod with small lobe cams to operates the intake and exhaust valves
Located on the bottom of the engineLocated on the top of the engine
Attached to the cam with a timing chainAttached to the crank with the timing chain
Powered by up and down motion from the pistonsPowered by the timing chain attached to the crank
Converts power from up and down motion of pistons to the transmissionProvides rotary motion to cam lobes to open and close valves

The key difference between the camshaft and the crankshaft is the camshaft regulates fuel flow and powers, while the crankshaft converts power to forward motion. The camshaft makes sure the valves function the way they were designed to function. The crankshaft provides the power to operate the vehicle. Both must work together for the vehicle to perform as designed. Is one more important than the other? Not really.

The main difference is if you have a damaged crank, you cannot drive. A damaged crankshaft is rare. It usually means time for a new engine. You can drive a car with a damaged cam, but it is not advisable. You will most likely risk further damage to the engine.

Read more: High Oil Pressure: Meaning, Causes, Symptoms, and Fix Guide

Tim MillerFounderOBD Advisor

I’m Tim Miller from Denver, Colorado. I’m the founder of obdadvisor.com, an automotive blog about "Diagnostic Tools and Auto Repair". My fan page is facebook.com/autozikcom. I've been working as an automotive mechanic and blogger for over 10 years writing articles to share my experiences and expertise.

Web: https://www.obdadvisor.comEmail: [email protected]
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