performance camshaft ultimate guide (What is the best camshaft type)

Unlocking greater engine performance and power requires the right modifications, and one crucial component to consider is the performance camshaft. By fine-tuning valve timing and openings, a performance camshaft can significantly enhance your engine’s capabilities.

In this article we go over key points, such as lobe lift, duration, and separation angle, which are essential in choosing the ideal performance camshaft for your needs.

performance camshaft

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what is a performance camshaft

An aftermarket or performance camshaft is a modified version of your engine’s stock or existing camshaft.

In the majority of cases, a performance camshaft will enhance engine performance by adjusting valve timing and openings.  This can be done by modifying the camshaft lobes in 3 main different ways including:

  • Lobe Lift
  • Lobe Duration
  • Lobe separation

what is a camshaft & what does a camshaft do

A camshaft is a fairly simple part, consisting of a metal rod or shaft with shaped lobes (cam lobes) located along it. 

When the shaft is rotated, the shape of the cam lobes allows it to put pressure on a valve or rod to the degree of its lobe shape, with the duration of action being controlled by the speed of rotation.

In a modern internal combustion engine, they are often located right above the cylinder banks (Overhead Camshaft (OHC)) or inside the engine block.(1)

Their calibration carefully controls the quantity and timing of valve opening. As a result, this regulates the amount of air that enters the cylinder and how effectively the exhaust gases from the prior ignition exit the chamber.

Because the opening and closing of the valves must be precisely and exactly synchronized with the motion of the pistons, they can have a major impact on performance.

The camshafts attach through a timing belt or chain to the rotation of the crankshaft, which is directly moved by the pistons inside the cylinder.  Furthermore, the form of the cams lobe is precisely engineered to regulate the rate at which the valves open and close.

performance camshaft lobe
Camshaft side view angle

How to choose the right performance camshaft

The following points are all the possible alterations or mods you need to take in account about your camshaft and its assembly.  They will explain what the different alterations are, how they work and what they do.

1. Performance Camshaft lobe lift

Lift is measured in fractions of an inch and represents the amount a cam lobe pushes a valve off its seat.

However, it’s crucial to understand the 2 different ways camshaft lift can be viewed and calculated.

  • Camshaft Lobe Lift
  • Valve Lift

The distance a cam lobe can moves a lifter/tappet for example will be measured in cam lobe lift, also known as Gross Lift. However, the actual valve lift (the amount the valve moves from its seat) is not the same as the “cam lobe lift”.

This is because a rocker arm can increase the movement of the valve. A cam with a lobe lift of .4 inch, for example, can move a valve .6 inches with a rocker arm ratio of 1.5:1 (1.5 x.4). (2)

Different rocker arm ratios will alter valve lift even if the cam lobe lift stays the same. You can thus enhance valve lift by increasing the rocker arm ratio.

More cam lift means the valve opens wider. By increasing cam lift, more air or exhaust can pass through an engine.

If you intend to upgrade your cam to improve lift, make sure your valve springs can handle the higher lift.

Additionally, the clearance between the piston and the valve can also be an issue. Before you pick up a new cam, be sure you have proper clearance.(3)

2. Performance camshaft lobe duration

Camshaft Duration is the length of time it takes for a valve to open and close measured in degrees of crankshaft rotation.

In other words, how many degrees of rotation the crankshaft travels during the open time of the valve.

Nearly all cam manufacturer rates camshafts based on duration. A duration specs of .050 inches is commonly used.

The majority of performance camshaft manufacturers agreed on a duration measurement standard so that all cams can be measured in a comparable manner.

The idea is to start measuring duration at .050 inches of the lifter/tappet movement. This can also be done using valve movement (again, .050 inches), however, the rocker arm ratio must be considered to ensure correct readings.

Finally, when someone refers to a “big” cam, they are referring to cams that have a longer duration. This leaves the valves open for a longer time, enhancing midrange and top-end power at the sacrifice of low-end torque.

A shorter duration performance cam has the opposite effect. A smaller cam increases low-rpm torque and drivability by not keeping the valves open for as long.

3. Performance camshaft lobe Separation angle

The Lobe Separation Angle (LSA) is the distance between the centerlines of the intake and exhaust lobes.

It’s measured in degrees of camshaft rotation. You’ll usually find the measurement between 104 and 118 degrees.(4)

This additionally indicates the location of the lobes on the camshaft.

The Lobe Separation Angle can drastically influence your performance camshaft effects on your engine even if the lift and duration stay the same.

Wide Performance camshafts LSA: A cam with a wider LSA (110-118 degrees) typically offers less overlap between intake and exhaust valve opening and closing movements.

This results in a broader rpm range, improved idle quality, and increased engine vacuum, but at the expense of decreased torque at low and medium rpm.

Narrow Performance camshafts LSA: A cam with a narrow LSA (104-109 degrees) produces more low and midrange torque but has a shorter operating range, choppy idle, and reduced engine vacuum.

Cylinder pressure rises as the piston draws air into the cylinder following the exhaust stroke. More air can be pulled into the cylinder if the intake valve opens earlier.

Camshaft lobe separation

4. The four types of camshaft

A standard in-block camshaft requires pushrods to reach the rocker arms connected to the valves. However, the pushrods and camshaft are separated by what is known as lifters.

A lifter’s primary role is rather straightforward. It sits on the camshaft and transfers the motions of the cam lobe to the pushrods.

Camshafts are classified into four categories based on the type of lifter used.

The different possibilities are a hydraulic flat tappet, a hydraulic roller, a solid flat tappet, or a solid roller.

5. Flat Tappet lifters vs Roller lifters

Flat Tappet Lifters

Flat tappets have a lengthy history of performance and reliability. Before the late 1980s, nearly every V8 engine had a flat tappet cam.

They are reliable and reasonably inexpensive. Finding a nice flat tappet cam for your street car is not difficult having hundreds of models to pick from.

Furthermore, flat tappet lifters are not flat. They feature a small crown on the lifter’s face.

The cam lobe is machined with a small taper, causing the lifter to ride the taper and spin as it rides the lobe.

It ensures that the lifter and camshaft wear evenly.

Flat tappet lifter

Roller lifters

Roller cams are hardened steel cams that use lifters with a roller, or wheel, that rolls over the cam lobes. The lobes of roller camshafts are also perfectly straight.

Roller lifters have a wheel supported by needle bearings and an axle mounted at the bottom.

This design significantly reduces valvetrain friction and wear, resulting in a longer service life. Furthermore, roller lifters are joined together or secured in some way to prevent them from spinning sideways and damaging themselves.

Roller cams allow for steeper lobes. This implies the valve opens faster and can stay at a higher lift for a longer amount of time.

This provides for greater airflow and power. Because of its superior performance and lower wear tendencies, roller lifters are now used in almost every engine.

6. Hydraulic or Solid?

Both flat tappet lifters and roller lifters and available as either hydraulic or solid form.

Here the difference between the two:

Hydraulic lifters

Hydraulic lifters are self-adjusting lifters. They use an oil-damped, spring-loaded plunger to self-adjust.

As the engine runs, the lifter’s body fills with oil, which, when paired with the spring, enables the plunger to move up and down as needed. This ensures that the lifters maintain zero valve lash (the distance between the valve stem and the rocker arm tip).

Hydraulic lifter cams are silent, need less maintenance, and deliver less shock to the valvetrain.

Their biggest disadvantage is that they can overfill with oil, causing the valves to float or stay open for too long at high rpm. Furthermore, when installed, hydraulic lifters may require an initial amount of preload.(5)

Solid Lifters

Solid or mechanical lifters are just what their name says: solid. It’s essentially a machined piece of steel without any moving parts.

Because of its simplicity, a solid lifter is incredibly reliable when set up correctly. However, because there is no internal self-adjusting mechanism, they require a small clearance to function effectively.

This clearance, also known as valve lash, and is critical for handling heat expansion.

Solid lifter cams are suited for more intense street and racing profiles because they are less susceptible to valve float at higher rpm. The disadvantages of using solid lifters are frequent valve lash correction and higher valvetrain noise.

Recommendations

Now that you know how camshaft specifications works and what are all the different types of camshafts we recommend you check out our other article: best aftermarket camshaft 2023: 5 brands you can buy now

We breakdown 5 different popular aftermarket camshaft brands so you can get the best quality on the market.

conclusion

In conclusion, a performance camshaft is an aftermarket modified version of the engine’s stock camshaft. It enhances engine performance by adjusting valve timing and openings.

There are three main ways to modify a camshaft: lobe lift, lobe duration, and lobe separation angle.

Lobe lift determines how far the cam lobe pushes the valve off its seat, while lobe duration measures the length of time the valve is open and closed. The lobe separation angle determines the position of the intake and exhaust lobes.

Choosing the right performance camshaft involves considering all three of these factors.

Additionally, camshafts can be categorized based on the type of lifter used: hydraulic flat tappet, hydraulic roller, solid flat tappet, or solid roller.