A camshaft is essential for optimal regulation of the engine’s valve timing. It directly impacts the engine performance, fuel efficiency, and emissions. With various types of valve arrangements, camshafts are customized to meet the specific engine requirements. It would start from the standard vehicles to high-performance motors.
Continue reading to learn every nook and cranny about the camshaft. Learn its types, common materials used to manufacture it, applications, and maintenance tips to ensure optimal engine operation.
What Is a Camshaft? Function Of the Camshaft
A camshaft is an important part of the engine component, designed to control the timing of the opening and closing of the engine’s valves. The shaft comes with the cams (lobes), which are responsible for the rotational motion.
In the internal combustion engines, the cam lobes push against the valves that regulate the intake of air and the exhaust of combustion gases. It is connected to the crankshaft with the timing belt or chain that ensures the valves operate at the right times. Such proper timing on the intended engine is important for the optimal performance of the engine with accurate emission of gases.
The Working Principle of Camshaft
The working principle of the camshaft is mainly determined by how it converts rotational motion into linear motion. It is mainly used to control valve timing in an engine. It does it through specially shaped lobes, or cams, that are mounted along the shaft.
When the camshaft starts rotating, each lobe pushes against a valve lifter or rocker arm. It helps open the engine’s intake or exhaust valve at a specific point in the engine cycle. Once the lobe completes the circle, the valve spring keeps the valve closed.
The complete spinning motion is directed by the crankshaft through a timing belt, chain, or gears. Both parts must move together at the right time so that the engine can run efficiently.
Some advanced engines utilize smart systems such as Variable Valve Timing (VVT). It mainly adjusts the valve timing dynamically and improves the performance. It even optimizes engine operation across various speeds and balances the speed.
Main Components Of A Camshaft
Lobes (Nok)
The lobe is often called the cams, which are the protruding parts attached to the camshaft. It is strategically designed to control the opening and closing of the engine’s valves. The shape and size of the lobes highly affect the timing and duration of valve movement. When the camshaft rotates, it starts running against the lifters, push rods, or rocker arms. It turns the valve open and closed.
Camshaft Journal
The camshaft journal is a cylindrical portion of the camshaft that works as the bearing surface. It is located along the shaft where the camshaft is connected with the engine block or cylinder head. The core purpose of this portion is to ensure a smooth surface for the camshaft that helps it to rotate within the engine without friction.
Timing Gear or Timing Sprocket
The timing gear in the camshaft mainly connects the two camshafts through a chain or belt system. The gear has teeth that engage with the chain or belt to transmit rotational motion. The goal is to ensure the camshaft and crankshaft rotate in sync and maintain the valve timing.
Camshaft Bearing
These are the actual bearings that house the camshaft journal. It is designed to provide support for the camshaft and reduce friction as the camshaft rotates. Through this, the camshaft remains properly aligned, especially when the engine is rotating at high speeds during engine operation.
Camshaft Locking Mechanism
This specialized mechanism holds the complete camshaft in a fixed position. It is a safety feature that ensures the camshaft rotates in the optimal direction and prevents it from shifting off the valve timing.
Push Rods
Push rods are long and slender rods that are used in certain engines and transmit motion from the camshaft to the engine’s valve lifters and rocker arms. It is commonly found in overhead valve (OHV) engine designs.
Rocker Arms
Rocker arms transfer motion from the push rods to the valves. Typically, they are pivoting levers that stand on the shaft or fulcrum and regulate the opening and closing of the valve. It maintains the correct timing in the engine cycle.
Valve Lifters (Tappets)
Valve lifters, also known as tappets, that directly contact the camshaft lobes. Theoretically, they are mainly the intermediaries between the camshaft and the push rods. The goal is to transmit the camshaft’s rotational motion into the linear motion that is needed to open and close the engine’s valves.
Types Of Camshafts Used In Different Industries
Based on Lifter / Tappet Type
Flat‑Tappet
A flat-tappet camshaft uses flat lifters that directly contact the cam lobes. It is typically made of steel or other strong materials and runs by sliding directly against the cam lobes.
Roller
The roller camshaft is the most commonly used part in the roller lifter, designed to reduce friction between the lifters and the cam lobes. It has a small wheel or roller at the contact point with the cam lobe.
Mushroom
A mushroom camshaft is found in the mushroom-shaped lifters that have a larger space compared to flat or roller lifters. It is used in applications where high lift and aggressive cam profiles are necessary, for instance, in performance engines.
Based on the Lifter Actuation
Hydraulic Tappet
A hydraulic tappet is a hydraulic lifter type that uses oil pressure to maintain constant clearance between the camshaft and the valve train components. It is mainly used to adjust the valve, ensuring that there is no excessive pressure on it.
Solid Tappet
Solid flat-tappet cams don’t have the hydraulic mechanism and require the manual adjustment of valve lash. It offers direct contact between the cam and the lifter. It has the fastest ever camshaft ramp profiles, which help enhance performance.
Hydraulic Roller
To reduce friction, hydraulic rollers offer a good combination of self-adjusting features with roller bearings. It is used for higher RPM operation that runs between ~7,000–8,000 RPM.
Solid Roller
Solid roller cams use the roller lifters and lack the hydraulic mechanism. It has a maximum RPM of 8,000+ RPM that offers superior stability at high speeds.
Based on Overhead Camshaft
There are three main types of camshaft drive:
SOHC (Single Overhead Cam)
The SOHC design uses a single camshaft per cylinder bank, which is mainly located at the engine’s head. This camshaft is designed to control both the intake and exhaust valves.
DOHC (Dual Overhead Cam)
The DOHC system utilizes two camshafts per cylinder bank—one is there for the intake valves and the other for the exhaust valves. These twin cams are better suited for high-performance engines.
Overhead Valve (OHV)
In the pushrod engine, a common camshaft is found in the engine block, which drives the valves through push rods and rocker arms.
What Are the Differences Between Single and Double Overhead and Overhead Valve (OHV) Camshafts?
Here is a quick table summarizing the difference between these common Single and Double Overhead and Overhead Valve (OHV) Camshafts:
| Feature | SOHC | DOHC | OHV (Pushrod) |
|---|---|---|---|
| Camshafts per Cylinder Bank | 1 | 2 | 1 |
| Valve Control | 1 cam controls both intake & exhaust | 1 cam for intake, 1 for exhaust | The camshaft in the block uses push rods |
| Valve Count per Cylinder | Typically 2 | 4+ | Typically 2-4 |
| Performance | Moderate | High | Moderate |
| Complexity | Low | High | Low |
| RPM Potential | Lower | High | Limited |
| Applications | Small cars, motorcycles | Sports cars, high-performance engines | Trucks, muscle cars, industrial engines |
Advantages and Disadvantages Of Camshaft
Here are the benefits and special considerations of using the camshaft in the application:
Pros
- Ensures the timely opening and closing of the valve
- Improves the engine performance, with the power output
- Offers efficient combustion, which leads to better fuel economy
- Customizable camshaft profile to meet specific performance needs
- Accurate camshaft timing reduces the harmful emissions
Cons
- Complex manufacturing
- Uncreases engine production costs
- Prone to frequent wear and tear over time
- Worn or improperly adjusted camshafts cause engine noise or vibrations.
- Not all camshaft designs are suited for high RPM ranges
What Material Is Used For Camshafts?
Camshaft is made from various materials. Here is the detailed overview of each material used in camshaft manufacturing, with the needed properties details:
Chilled Cast Iron
It is the most common type of camshaft material that is used for its impressive hardness at all surfaces. Through rapid cooling during the machining process, it creates a hard outer surface and maintains a more ductile inner core. You will commonly find it in the camshafts of standard production engines. This is like economy cars and light-duty vehicles, as well as some smaller designs.
Steel
These types of materials are made from carbon or alloy steel, which is processed with extensive heat treatment and increases its hardness. Steel camshafts are resistant to fatigue and can easily handle high-performance engines. It is used in performance engines, sports cars, and muscle cars. Sometimes you will see it in the heavier-duty trucks and industrial engines.
Alloy Steels
These types of steels are alloyed with some essential materials like chromium, molybdenum, and vanadium that enhance the strength and hardness. It offers superior wear resistance in the engine, even compared to the basic carbon steel. You will find it used in motorsport and performance street cars.
Billet Steel
This highly quality material is made from a single, solid block of steel, which is mainly used to shape the camshaft. It offers excellent strength that helps the camshaft to withstand any high mechanical loads and vibration. This camshaft is used in drag racing, rally racing, and many other high-end performance vehicles.
Forged Steel
Forged steel is manufactured by heating and then compressing steel under high pressure. It improves the material strength and makes it ideal for high-stress applications. You will find the camshaft in racing applications, muscle cars, and performance street cars.
Billet Steel
These steels are made from solid steel rods and used to manufacture the camshaft’s lobes and journals. It offers vast customization options for the camshaft profile. These types of camshafts are mostly found in racing and high-performance applications.
Nitriding Steel (EN40B)
Nitriding steel, such as EN40B, is a high-quality alloy steel that is manufactured under the nitriding process. This special process helps improve the material’s wear resistance and fatigue strength. It also improves the corrosion resistance of the camshaft and its application. You will find the camshaft used in racing engines, motorsport engines, and heavy-duty industrial engines.
Major Considerations to Select the Right Material for Camshaft
Durability and Longevity
Camshafts continuously face higher friction while performing. It is usually with the contact against the lifters, rocker arms, and valves. Choose the material that can withstand constant cyclical loads without failure. For instance, chilled cast is the best option that can last up to 150,000 miles in standard applications. In contrast, the billet steel can go over 100,000+ RPMs with proper maintenance.
Operating Conditions
Camshafts operate in high-temperature environments. Push engines experience different loads at various RPMs. So the material you will choose must withstand these fluctuations without deforming. For instance, alloy steels like EN40B can withstand temperatures up to 1,200°C.
Performance
Performance engine types found in motorsports need camshafts that can ensure higher RPMs. It should provide higher tensile strength and resistance to wear. Billet steels and forged steel are used to ensure higher RPMs, no matter how forceful the environment is.
Compatibility
Different engine types, such as SOHC, DOHC, and OHV, require different types of material. For instance, if you are using engines with more than two valves per cylinder, make sure you use the material that can handle more complex valve timing without fail. Chilled cast iron or steel is the best choice for its durability.
| Engine Type | Suitable Material |
|---|---|
| SOHC engines | Chilled Cast Iron, Steel |
| DOHC engines | Forged Steel, Billet Steel |
| OHV/Pushrod engines | Forged Steel, Alloy Steels |
Surface Hardening
Surface hardness of the chosen material is a must to ensure optimal performance of the camshaft in the specific engine. Nitriding material can increase surface hardness by 50% or more. Induction heating is mostly used here for hardening camshafts and making them more resistant to wear and fatigue.
Applications of Camshaft
Automotive
In automotive engines, the camshaft is the most important part to control the valve timing, maintain the engine power, and improve fuel efficiency. Plus, in modern vehicles where advanced camshaft designs are required, the DOHC camshaft offers better performance with optimal emissions control.
Motorcycles
Motorcycles use the camshaft as an integral part of engine design to control the valve timing and ensure high RPM operation. They are typically lightweight so that it can enhance the performance without adding unnecessary bulk.
Heavy Machinery
Heavy machinery, such as construction equipment, uses camshafts to handle the extreme loads and long operating hours. The camshafts used here are typically larger, with more industrial designs that can manage mechanical stress easily.
Aerospace
Both commercial and military aircraft utilize the camshaft to ensure precise performance in the turbine engines. Besides, spacecraft engines use a high-performance camshaft to control critical timing components.
Marine
Marine engines, including those in boats, ships, and submarines, highly optimize the camshaft to ensure the optimal valve timing and fuel efficiency. Marine camshafts are made from stainless steel or corrosion-resistant alloys that can prevent rust and wear.
Motorsport
In motorsport, camshafts are important to optimize the performance at high RPMs. It offers higher tensile strength and resistance to wear. For instance, Billet steel and forged steel are used due to their higher durability, ensuring camshafts can withstand the extreme conditions.
Industrial Engines
Industrial engines, often used in power generation, pumps, and compressors, demand a high-end performance-level camshaft. It is mainly to operate continuously for extended periods under varying loads. Here, camshafts optimize the timing of the valves in various machines like air compressors and water pumps.
Agricultural Equipment
Many agricultural equipment, such as tractors and other machinery that have internal combustion engines, use camshafts. It is used to open and close the engine’s intake and exhaust valves, ensuring an efficient engine operation.
Diesel Engines
Diesel engines tend to have more conservative valve timing than gasoline engines. The camshafts used here are designed differently to accommodate the high compression ratios. For example, the Cummins ISX 15-liter diesel engine uses longer valve overlap to have high torque output at low RPMs.
How to Maintain and Care for a Camshaft?
Regular Oil Changes
Due to long-term performance, it is common for the oil in the cam to get first, causing abrasive wear on cam lobes and bearings. Use high-quality engine oil and change it at the manufacturer-recommended intervals to maintain the lubrication.
Keep the Engine Clean
Dust and grime inside the engine block the oil passages around the camshaft. All you need to really flush your engine. You can use the air filters to ensure better oil flow.
Proper Lubrication During Installation
When installing a camshaft, make sure to apply an exact amount of lubricant to its journals and lobes. It helps to prevent dry contact at the initial stage.
Monitor Camshaft Timing
Regularly check the camshaft timing with the use of a timing light or diagnostic tools. Otherwise, there will be a chance of engine misfires, poor fuel efficiency.
Avoid Overheating
While running the engine, check and ensure the engine is also cooling optimally. For instance, check the radiator, thermostat, and coolant levels.
Regularly Inspect for Wear and Tear
Inspect the camshaft for signs of wear, such as pitting, scoring, or discoloration. It might be the result of excessive friction or lack of lubrication. Repair the issue as soon as possible to prevent the core engine failure.
Check Valve Spring Pressure
Always be regular in checking valve springs for any sign of weakened portions or wear. Use a valve spring tester and ensure they are within the recommended pressure range.
In Closing
If you want to get the best engine performance, the camshaft should fit your engine’s specific requirements. To ensure top-quality camshafts, with the expert suggestions and CNC machining services, RICHCONN is here for you.
We specialize in CNC machining to build high-performance engine components. Our CNC machining service is well-suited for automotive, motorsport, industrial engines, and more. Contact us to get the right camshaft material and design for your needs.
Frequently Asked Questions
What is the role of a camshaft in an engine?
The camshaft plays a big role in controlling the timing of the engine’s intake and exhaust valves. It helps engines to take in air and fuel and expel exhaust gases at the right time.
Can a camshaft be repaired if it gets damaged?
Yes, you can easily repair the damage to the camshaft, but it depends on the extent of the damage. Minor wear or surface imperfections can be machined, whereas you need to replace the whole part for severe damage.
How does camshaft material affect engine performance?
The materials used in the camshaft play a big part in determining how much strength, wear resistance, and durability it provides during operation. Stronger materials help to get higher RPMs, whereas softer materials limit the engine performance.
What’s the difference between a camshaft and a crankshaft?
The camshaft controls the timing of the engine’s valves. It ensures the right timing of opening and closing the valves. On the other hand, the crankshaft converts the up-and-down motion of the pistons into rotational motion. It helps to power up the engine to start.
How long does a camshaft last?
The factor depends on the maintenance and engine type. But with the optimal care, it can run many miles, often exceeding 150,000.
