What Does Camming A Truck Do?

Dustin Hawley | Feb 11, 2021

The term “camming” refers to the modification of a truck’s camshaft. While it may sound justifiably complex, the process of changing out the camshaft allows you to build a custom engine that performs better within a particular RPM range.

camshafts and engine components

But why would you want to do this? And even with good reason, is it really worth your while? Let’s take a closer look at camming and what it does for your truck.

How Does A Camshaft Work?

A camshaft is a metal rod that drives an engine. There are one or more cams, or irregular lobes, that actuate parts of the machine along the rod. As the shaft rotates, the larger parts of the lobes can drive levers or pistons.

The earliest camshafts date back to the 13th century when Arabs used them to operate water mills. They quickly spread throughout the civilized world, but their use was limited until the industrial revolution. Since that time, camshafts have become an essential part of engine design.

In an engine with multiple pistons, such as a truck motor, the pistons don’t fire simultaneously. Instead, they fire in a sequence, one after the other, and the motor’s camshaft raises and lowers the pistons to determine the firing sequence.

The camshaft activates a cylinder’s intake and exhaust valves. One lobe will activate the intake valve, followed by a second lobe that activates the exhaust valve. As the shaft rotates, the valves will open and close in the appropriate timing.

Moreover, a camshaft determines the duration and nature of the ignition process. For instance, the intake valve may open for a longer or shorter period of time during the upstroke. A small change in this duration can make a big difference in how the engine performs.

Different camshafts will allow the vehicle to perform better under certain conditions. For example, allowing more fuel into the cylinder is wasteful at low RPMs, but provides more power at higher RPMs.

However, most stock camshafts are generalists and perform best during everyday driving. But if you have a heavy load or you’re racing, you may want a shaft that’s engineered for your specific purpose.

Why Install A Custom Camshaft?

Custom camshafts are designed with larger, wider lobes than factory shafts. As a result, the intake valves are open for an extended period. This provides additional power and efficiency at higher engine speeds.

While this may sound like an easy decision based on the benefits, camming a truck is not without its downsides. While increased fuel intake is helpful at higher speeds, it’s actually detrimental to your performance at lower speeds. Specifically, your low-end torque will suffer, which can prove problematic for a work truck or for towing since you need a lot of torque to get started with a heavy load.

That being said, many truck owners simply prefer a custom camshaft for aesthetic reasons. Yes, it’s inefficient at slow speeds, but it also provides a distinctive, aggressive rumble that makes the engine sound deeper and richer.

The downside here is obvious - your gas mileage and towing performance will clearly suffer. However, if you want a deep, roaring engine, camming may be a worthwhile option.

FAQs About Truck Camming

So, what can you expect if you cam your truck? Here’s a quick overview of truck camming basics.

Does Camming A Truck Make It Faster?

In most cases, yes, but it depends on the model of the truck and which custom cam you use. With that said, aftermarket cams are designed for high-end performance, so you can typically expect to experience faster speeds after camming a truck.

Are Bigger Cams More Powerful?

Yes. A bigger cam will open the intake valve wider, allowing more fuel and air into the cylinder. The larger the cam, the more fuel that is let in.

Does Cam Timing Make A Difference?

Yes. Adjusting the camshafts so the cams are slightly ahead or behind will alter the engine’s performance. 

Advancing the timing will cause the fuel intakes to open and close earlier, which improves low-end torque. Conversely, retarding the cam will improve high-end horsepower at the expense of low-end torque.

What Is A Lope?

A lope is a distinctive, rhythmic rumble that occurs when an engine is idling. It’s highly undesirable for performance, but the sound is much sought-after by gearheads who want their performance truck to sound like a performance truck.

A lope is caused by extremely large and wide cams. When cams are wide enough, they will overlap, so in other words, the intake on cylinder two will open before the intake on cylinder one is closed.

In addition to the unique sound, a lope is actually desirable when racing. At very high RPMs, the longer valve times will allow for plenty of fuel to enter the cylinders, even as the cam quickly rotates. As a result, the truck won’t lose power when approaching redline.

Why Are Cammed Trucks Louder?

The main reason that cammed trucks are louder is that there’s more fuel going into the engine, meaning a louder idle and more volume at any given speed.

While this is mostly true, the extra noise doesn’t just come from increased fuel intake. It also results from the larger size of the cams themselves. Steeper angles and wider valve openings create more mechanical noise. 

Why Do Camshafts Break?

Camshafts usually break because of a failure elsewhere in the engine. Connecting rods and other parts can break loose and strike the shaft. They can also fail due to defects in manufacturing, such as microfractures. In the rare instance that this occurs, failure usually happens relatively quickly.

How Much Does It Cost To Cam A Truck?

Assuming you provide your own new camshaft, most shops will charge between $600 and $1,000 to cam your truck. If you plan on doing the job yourself, make sure you set aside an entire weekend. Though it’s not terribly difficult, it can be very time-consuming.

Summary

Though it can bring many performance and cosmetic benefits, camming is not the right choice for everybody. In fact, for most purposes, your truck will perform best when using the factory camshaft. However, if you’re using your truck for performance-related reasons, like racing, you may want to consider installing an aftermarket shaft. To learn more about maintaining and modifying your truck, read more of our trusty guides!

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