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How To Choose a Camshaft for a Small Block Chevy?

Building a powerful engine involves choosing parts in a hierarchy based on their criticality. For example, choosing cylinder heads with high airflow and good chamber design is by far the best way to maximize an engine’s performance. Still, no matter how good cylinder heads might be, the camshaft will determine how well they perform on a given engine combination. So, How to choose a camshaft for small block chevy?

Choosing the right cam for small block Chevy is more crucial for engine performance than any other part since the valvetrain acts as the conductor for the engine. The airflow numbers in the cylinder head are meaningless if the valves aren’t opening correctly, at the proper height, and for the appropriate amount of time.

“It may take years of education and an engineering degree to gain a solid understanding of camshaft fundamentals. However, you may be able to qualify for the top 10% of rodders by picking your next camshaft the right way rather than by merely guessing and scrolling through part numbers. Understanding the basics is vital, and the most crucial factor is how those basics translate into your driving experience.”

Camshaft Overview

Several types of camshafts are available in the market. But how to choose a camshaft for small block chevy still is a crucial task. Valve closure and opening in piston engines are controlled by linear motion. During rotation, the rod’s lobes (cams) push against the valves on the engine pistons, causing the valves to close and open. Hence, a camshaft can be seen as a device used to open and close the valve for an engine’s piston. Camshafts are located above the engine’s cylinder head for modern machines.

Single overhead cam (SOC) engines and dual overhead cam engines are both available. In the DOHC engine, two camshafts are used (intake and exhaust), while in the SOHC engine, one camshaft is used. Furthermore, camshafts are usually forged from metallic materials such as cast iron or steel. This ensures rigidity. Since the shaft keeps rotating, regular intervals must be maintained for the valves to open and close. Discover how a typical engine’s camshaft works in the following paragraphs.

How does it work in the engine?

The piston engines are equipped with camshafts. They have more than one piston on each cylinder. However, a single cam cannot drive all the pistons. A camshaft is a shaft that has numerous cams on it. Having an understanding of the camshaft’s working principle involves knowing what happens when it rotates. The piston’s valves are pressed by the shaft rotation as various processes co-occur.

Specifically, they are the intake process, the exhaust process, the compression process, and the ignition process. During the same time frame, the camshaft controls valves take in fuel/air and shut down the exhausting ones. Consequently, the timing has to be near-perfect as much as possible.

Chains (to the crankshaft) or timing belts connect the camshafts to the engine to ensure accurate timing during each process cycle. A camshaft’s shape affects the opening/closing speed of the valves, as well. Therefore, a variable valve timing process refers to checking out the profile. One of the major things which bother many is how to choose a camshaft for small block chevy?

When does a camshaft need to be replaced?

Consider having the camshaft of your car replaced if it is beginning to make noises before starting. The lobe design of the camshaft can also wear out over time, which warrants a camshaft change. Therefore, a camshaft change is not often necessary unless there is an obvious fault. But be smart and aware of how to choose a camshaft for small block chevy.

“Despite apparent faults requiring a camshaft change, this is not the only reason for a replacement. Most modern engines feature camshaft lobes that are resistant to noticeable wear and tear. In addition, some camshaft’s lobes are not even visible from the top, so wear in the camshaft is often missed.”

Consequently, we recommend that you consider your budget when deciding whether to change your camshaft. Identify how much a replacement might cost compared to using what you currently have. The best solution is to have the camshaft machined by a machine shop with modern tools suitable for modern camshafts. Although, it would be best never to hesitate to get a replacement if you noticed signs of wear.

Which is the best street cam for Small Block Chevy?

The result is almost the same as having no engine at all if the camshaft is not suitable. Camshafts play an essential role in a machine because they are responsible for the flawless operation of valves. How to choose a camshaft for small block chevy? Choosing the proper camshaft for your small-block Chevy requires more than just consulting an engine builder.

“Many variables will influence the performance of your engine. Understanding camshaft design at the fundamental level is essential before you start comparing numbers. Knowing how each number affects your engine’s performance increases the likelihood of selecting the best camshaft based on knowledge rather than guesswork. The builder will be able to work according to your description if you know cams.”

We suggest you start by following these steps:

What you want must be realistic and honest

Even though this sounds simple, it is a rule that is often ignored, which leads to a lot of dissatisfaction between engine builders and customers. Be honest about the engine’s intended use if you wish to avoid over-camming a small block Chevy.

Make sure your car is compatible with the engine

To choose the right engine for your vehicle, you will also need to consider the average running requirements of the vehicle.

Do not build the engine around the camshaft

In contrast, you should always focus on the engine before the camshaft. Depending on the engine’s airflow capabilities, the right camshaft will open and close the valves at the right time.

Checklist before selecting a small block Chevy camshaft

After identifying the necessary factors to consider, you should select the proper camshaft for your small block chevy.

Price

It is essential to consider your budget, even when it is advised to always opt for the best quality. Considering how popular small-block Chevys are, there’s a high chance of finding one within your budget that’s both high and low speed-capable at the correct RPM.

RPM Range

The cam should always be designed around the engine, as we said earlier. The operating range of your engine determines the camshaft’s RPM range that will produce the most power.

Lift

The valve lift must be at the right level and not too low or too high for the engine to operate correctly. Having the perfect valve lift ensures air and fuel mix in the right proportion for optimal combustion.

Compression Losses

The best cam for your small-block Chevy should close very quickly and tightly too. The incorrect cam opens the exhaust valves too far and robs the engine of air.

Lobe Separation Angle

The centerline of the intake cam and exhaust cam is the angular relationship between them. An angle between the cam lobes of the intake and exhaust valves determines when the valves open.

Performance & Compatibility

To determine the cam choice that best fits your needs, you must first decide which torque value you want.

How to choose a camshaft for small block chevy?

Every hot rodder wants their street machines to sound the part, whether driven daily or on the street and strip. When you’re pulling up to a traffic light, there’s nothing better than the syncopated music of a choppy idle. Because race engines rely on high rpm operation, the sound is more of a side-effect. The camshafts of their engines need to be ground longer and with a higher lift to run at higher RPMs.

“However, in a streetcar, a common mistake is to choose a camshaft that isn’t well matched to the engine. The camshaft can also be selected by using camshaft selection software. You can also use the camshaft selection calculator before selecting cam for small block Chevy. This will increase rpm as the valve lift and duration increase. Finding the right balance between performance and drivability is what makes matching a camshaft easier with experience.”

What are the signs which show that your camshaft is damaged?

A camshaft has a device called a position sensor. An automobile’s Engine Control Module (ECM) receives real-time information from this sensor about your camshaft.

However, this camshaft sensor is essential for determining the state of the engine in conjunction with the crankshaft sensor. The sensor will report if your camshaft has already failed and is having issues. Unfortunately, sensors are susceptible to damage. Mechanics may be faulty, or wear and tear may be the reason for this.

Certain features may be exhibited when these sensors become spoiled:

  1. You might have trouble starting your car.
  2. The car becomes shaky when you drive it.
  3. Errors indicating that the engine light needs to be checked.

Camshaft Problems & How to Avoid and Fix them

There is no manufacturer’s error with most camshaft with small block Chevys, as some people believe. Instead, improper installation techniques and damaged cam parts are often the culprits.

Listed below are some of the most common causes of camshaft problems.

Applying Old Lifters on New Cams

The main caution here is not to use old lifters with a new camshaft. The best way to deal with this is to replace and install new lifters. Another consideration is not to use different lifters for different cams.

Lobe Wear

It’s important to note that using the wrong lubricants during installation is the significant cause here. Hence, applying only the manufacturer’s oil to the cam lobes, distributors, and camshaft gears is advisable.

Broken Camshaft

Having loose rotating parts in an engine is terrible. It might result in the camshaft being broken by another rotating part. Broken camshafts can also be caused by rough handling during purchase or installation.

Distributor gear wear

Using high-pressure oil can often lead to a reduced lifespan of the cams and distributor gear. Wears of this distributor gear can be mitigated by providing maximum up and down movement of 0.010 inches. Along with the currently listed issues, there are other possible camshaft problems, such as improper break-in methods, incorrect valve spring pressure, and mechanical interference.

Frequently Asked Questions

How do the right camshafts benefit the engine?

A camshaft is like the key that unlocks the door of an engine. To improve the engine performance and improve the fuel efficiency of your vehicle, you must choose the right cam for a small block Chevy. However, you’ll also benefit from increased torque and horsepower.

What are the differences between a small-block and a big-block Chevy?

Small block Chevys are lightweight and smaller than big block Chevys. Their weight makes them more maneuverable and able to accelerate faster than a big block Chevy. Compared to a small block, a big block Chevy is heavier, has more valves and bores, and produces more power. The piston strokes are also shorter on small-block Chevys.

What is the difference between a camshaft and a crankshaft?

There is a difference between them. Camshafts are mounted above cylinders and connected to a timing belt for smooth opening and closing of valves. Crankshafts, on the other hand, are mounted below the cylinders. During piston movement, they convert it into rotational motion for the flywheels. Using this rotational motion, the internal combustion engine can convert its torque ultimately.

What constitutes over-camming?

A valve that opens too wide and takes an extended amount of time to close indicates that your vehicle is over-cammed. Thus, compression losses occur, and the fuel/air ratio is affected.

How do I choose the best camshaft for a small block chevy?

It depends on the type of engine you’re going to run and some other essential factors what kind of camshaft you should pick for a small block Chevy. The exhaust gases cannot enter the intake valves when the cam lobes are separated by 107 degrees. This camshaft can be used with automatic and manual transmissions.

Conclusion

While the selection criteria for how to choose a camshaft for small block chevy is not so straightforward, you’ll agree that it’s not as difficult as it seems. The end goal is what matters: having a higher-performance engine that depends on how you intend to use it.

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