Camshaft – What Is It And How Do They Work?




You may have heard the word camshaft and cam’s thrown around by car owners, but never really understood what they were. Camshafts operate on relatively simple physical concepts and have been in use for well over 100 years in cars. They’re necessary for the function of internal combustion engines, and they can affect the performance of your vehicle. This is why it’s so important to know what camshafts are, and how they work. 

The Function 

A camshaft is essentially a metal rod that works to convert rotational motion into linear motion. In internal combustion engines for automotive vehicles, a camshaft is responsible for inputting fuel and expelling exhaust fumes. A few cams, or lobes are part of the camshaft and are used to move intake/exhaust valves. Camshafts are attached to crankshafts, which can be done using a few methods. This keeps the valves moving in relation to the movement of the pistons. Since internal combustion engines use multiple pistons, you need a rode covered with cams (or lobes) to work properly. The spacing and the placement of the lobes must be precise to ensure that the movement of the valves is properly calibrated. 

The Basics 

The size and shape of the lobes impact how the engine performs at various speed brackets. If there is a relationship that exists between these two factors, obviously you want a camshaft that encourages performance. The higher the RPM the faster the valves are closing/opening. With a four-stroke engine, the valves are opening and closing at about half the RPM range, so if they’re at a 2000 RPM range this happens 1000 times per minute. Because fuel intake and air are entering at such a high velocity at this point, if the intake valve were to close suddenly there would be no more input. 


If you own a Chevy vehicle, the placement of the cams is important in order to keep the intake valve open, especially considering you want the intake valve to stay open at higher RPM ranges. In a detailed review for Chevy owners, it’s explained that camshafts operate according to specific engine types. That means you need to have an understanding of what your engine block is before purchasing a camshaft kit for your vehicle. 

Configuration Of Camshafts 

Because there’s variation in how fast valves open at different RPM ranges, most camshafts will only function optimally at certain speeds. To circumvent this, automotive manufacturers have come up with varying camshaft configurations. Camshafts can be configured into multiple types, including single overhead cams, double-overhead cams, or pushrod engines. In single overhead cams, they may have one cam per head for cylinder engines but will have two cams for V engines. These operate based on springs and rocker arms. Double overhead cams operate on the same ratio as single overhead cams. That means for inline engines they will have two cams per head, while V-6/8 engines have four. Because the amount of valves is correlated to engine power, the advantage of these cams is to increase intake and exhaust input/output. 


Pushrod engines tend to use chains or gears as opposed to the belts used in overhead engines which are more likely to break. Pushrod engines utilize rods through the engine block, and these create a heavier engine. Due to the increased resistance to the springs, pushrod engines become limited in speed. This means that overhead cam engines can function faster because there isn’t an increase in resistance on the springs due to the rods. 

Performance Camshafts 

So know that we’ve dived a little into what camshafts do and what their configurations are, what’s the point of installing a performance camshaft? Well, stock camshafts may not have cams that work towards optimizing an engine’s performance. That is, the cams on a performance camshaft may allow more time for the valves to open and have a free exchange of gases. This doesn’t guarantee an increase in performance, as it may not be the camshaft itself that’s affecting engine power. It’s important to do your homework depending on your engine block and the type of camshaft kit you want to install. 


Camshafts have been in use for a long time, and they likely aren’t going anywhere as long as internal combustion engines are around. You can install camshaft kits to increase the performance of your vehicle. There’s a huge variation of cam size and proportion and they suit specific engine types, so you’ll need to know this information before looking for a performance camshaft. There you have it, now you’ll be able to understand what a camshaft is, and the function that it serves.