Brake S Camshaft

What is Brake S Camshaft

The brake camshaft of a truck is a crucial component in the vehicle's braking system. Its primary purpose is to control the operation of the brakes, such as the brake drum or brake disc. When the brake camshaft rotates, it influences the movement of the brakes through its cam profile, achieving the braking effect. This design allows the brake camshaft to precisely manipulate the brake's action based on the vehicle's braking needs.

Advantages of Brake S Camshaft

Valve timing control
The primary function of the camshaft is to control the opening and closing of the engine's intake and exhaust valves at specific intervals. The camshaft is designed with cam lobes or lobes that are positioned to push against the valve lifters.
As the camshaft rotates, these lobes actuate the valves, allowing air and fuel to enter the combustion chamber during the intake stroke and allowing exhaust gases to exit during the exhaust stroke.

Valve lift control
The shape and size of the cam lobes on the camshaft determine the amount of valve lift. A higher cam lobe profile results in greater valve lift, allowing more air and fuel to enter the engine, which can increase engine power and performance.

Valve duration control
The duration for which the valves stay open and closed is crucial for engine efficiency and power. The shape and arrangement of the cam lobes on the camshaft determine the valve duration. Properly timed and balanced valve duration ensures optimal engine breathing, fuel efficiency, and power output.

Valve overlap control
In some engine designs, the intake and exhaust valves overlap during certain points in the engine's operating cycle. This valve overlap is controlled by the camshaft and can influence engine performance characteristics, such as scavenging exhaust gases and improving low-end torque.

Camshaft synchronisation
In engines with multiple camshafts, such as dual overhead cam (dohc) or overhead camshaft (ohc) configurations, the camshafts must be synchronised to work in harmony. Timing belts, timing chains, or gears connect the camshafts to the crankshaft, ensuring that the valves are open and closed at the correct times concerning the engine's pistons.

First 12 3 Last 1/3

Why Choose US

Our Factory

Fuhui Auto Parts Co., Ltd is located in the famous hometown of oversea Chinese-Quanzhou city of Fujian Province. Founded in 1986, Fuhui is a high-new technology company which is professional in R&D and manufacturing auto parts and engineering machine parts.

Our Product

Our main products are brake camshafts(S-camshafts) and equilizer pin for the axles of heavy trucks, semi-trailer, trailer and passenger car.

Our Certificate

The company through the IATF16949:2016 International Quality Management System Certification. Our self-invented new CNC convex wheel milling machine gained rewords and won the Paris International Silver Trophy on the 7th International Exhibition of Inventions, New Techniques and Products, Kunshan.

Our Service

We always stick to the concept of " Quality First, Credit First", and offer high quality products with reasonable price and considerate service for customers. We sincerely welcome new and old customers at home and abroad to contact us and seek cooperation for mutual benefits.

Materials for Making Car Camshafts

Camshafts come from quite a range of metals with the type of material used determining properties such as durability. Below is a list of materials camshafts you can consider:

Hardenable iron
This material falls under grade 17 cast iron and it also consists of about 1% chrome to produce a range of 5-7% carbide. Hardenable iron can serve as a substitute for steel camshafts. It is applicable in areas where there is an overflow of oil.

Chilled chrome cast iron
It also contains 1% chrome, like hardenable iron. This material is more compatible with the casting process of manufacturing camshafts and is suitable for manufacturing high-quality and large quantities of ohc operating camshafts. However, it's more expensive than the other types of cast iron, it has strong resistance to unfavorable conditions.

Carbon steel (en8/en9)
It is applicable for producing roller camshafts and hardened camshafts because of its excellent properties and hardened attributes.

Nitriding steel (en 40b)
En 40b is the best option for camshafts. It is the steel version of chilled iron known for its hard surface finish and is one of the few lightweight automotive part materials.

Parts of a Camshaft

Like other car parts, the camshaft comprises various parts, some of which include:

Parts of a camshaftCam: This is the most important part of a camshaft. It is responsible for the closing and opening of the valves.

Cam follower: The part of the camshaft that has been driven.

Driveshaft: This feature enables movement of the whole camshaft's structure, and we see it linked with a belt to another engine's part called the crankshaft or works autonomously.

Shaft: This is the supporting component of the camshaft, and it binds the other parts together. It can endure stressful workloads while the combustion engine is running.

Bearings: This part makes sure that the shaft is in its upright position. It is also an important component because it helps reduce friction when the camshaft is in operation. Additionally, it has a special tool for replacing the oil in the camshaft.

Lobes: This structure provides the camshaft with the opportunity to exchange fuel-filled gases. Also, the lobes' speed is relative to the engine's speed.

Chain sprocket: Has a connection to the camshaft at one end. In addition, the chain sprocket along with the timing belt help keep the timing between the camshaft and crankshaft in sync.

How to Check the Camshaft

● Check the oil feed pipe for any blockages.
● Clean and inspect the cam bearings for scratches and wear.
● Clean and inspect the cam lobes for damage.
● Check the shaft for cracks.
Measure the cam lift: you can do this using a digital caliper. Firstly, you'll need to measure the diameter of the cam base circle. Next, you will need to measure the largest diameter, known as the base circle and lobe lift. You can then calculate the cam lift by subtracting the base circle diameter from the base and lobe lift value.

Types of Camshaft Drive Mechanisms

Single overhead cam (sohc) - One camshaft per cylinder bank. These mechanisms were particularly popular in the 60's and 70's. Advantages: They are reliable, cheap to maintain, and lightweight.

Dual overhead cam (dohc) - Two camshafts per cylinder bank. Most modern vehicles use dohc mechanisms. Advantages: These engines have a higher horsepower, are quieter, and allow car owners to separately tune the intake and exhaust valve timing, increasing efficiency.

Overhead valve (ohv/pushrod) - Like ohc engines, the valves are located in the cylinder head, however, the camshaft is installed inside the engine block. They include long rods which reach up to the head to move the rocker arms and actuate the valves. Advantages: These mechanisms are often more compact, cheaper to produce, and some have a better low-end torque than ohc mechanisms.

How Does Camshaft Work

Here's a step-by-step explanation of the working of the camshaft:
Step 1: Installation
The camshaft is positioned inside the engine block and is supported by bearings. It runs parallel to the crankshaft and is driven by the engine's timing mechanism, which can be a timing belt, timing chain, or gears.

Step 2: Lobes
There are several lobes, each corresponding to a specific valve in the engine. The number and shape of these lobes depend on the engine's design and the number of valves it has. In a typical four-stroke engine, you'll find one lobe for each intake valve and one lobe for each exhaust valve.

Step 3: Valve lifters and followers
The camshaft lobes press against valve lifters (also known as tappets) or cam followers (also called rocker arms). These components are in contact with the engine valves. The lifters or followers transfer the motion from the camshaft to the valves.

Step 4: Valve timing - intake stroke
As the engine rotates and the camshaft turns, a lobe responsible for the intake valve approaches the corresponding valve lifter or follower. The lobe's shape is designed to lift the lifter or follower, causing the intake valve to open at the right moment during the engine's intake stroke.

Step 5: Valve opening - intake stroke
When the intake valve opens, the engine's piston moves down, creating a low-pressure area inside the cylinder. This allows the air-fuel mixture to be drawn into the cylinder from the intake manifold.

Step 6: Valve timing - compression stroke
After the intake stroke, the camshaft continues to rotate. The intake valve closes due to the shape of the cam lobe, sealing the combustion chamber.

Step 7: Valve timing - power stroke
As the engine piston moves up during the compression stroke, another cam lobe corresponding to the exhaust valve approaches its lifter or follower. This lobe lifts the lifter, opening the exhaust valve at the right time.

Step 8:Valve opening - exhaust stroke
With the exhaust valve open, the burnt fuel-air mixture is expelled from the cylinder and pushed into the exhaust manifold as the piston moves down during the power stroke.

Step 9: Valve timing - exhaust stroke
After the power stroke, the exhaust valve closes due to the camshaft's rotation, sealing the exhaust port.

Step 10: Repeating the cycle
The camshaft continues to rotate, repeating this process for each cylinder in the engine. This series of events happens rapidly, coordinating the intake and exhaust valve timings for optimal engine performance.

What Is the Construction Process of a Camshaft

Material selection
Camshafts are usually made from forged steel or cast iron. The selection of material depends on the engine's design and performance requirements.

Design and engineering
Engineers create a design for the camshaft based on the engine's specifications, intended performance, and other factors. This design includes the shape and profile of the cam lobes, their spacing, and the overall dimensions of the camshaft.

Camshaft blanks
The manufacturing process starts with obtaining camshaft blanks. These are typically cylindrical pieces of the chosen material that will be machined to form the final camshaft

Machining
The camshaft undergoes precision machining using computer numerical control (cnc) machines. This involves several steps:
-Turning
The camshaft blank is placed on a lathe, and excess material is removed to achieve the desired diameter and length.
-Cam profiling
The cam lobes are machined into the camshaft using specially programmed cnc machines. The profile of each lobe is based on the design specifications. This process is crucial, as the shape of the cam lobes directly affects engine performance.
-Heat treatment
After machining, the camshaft is heat-treated to improve its hardness and durability. The specific heat treatment process may vary depending on the material used.
-Grinding
After heat treatment, the camshaft undergoes precision grinding to achieve the final dimensions and surface finish. This step is essential for ensuring smooth operation and reducing wear.

Finishing
The camshaft may go through additional finishing processes to ensure the highest quality. This can include polishing, shot peening and balancing to eliminate any potential imbalances that could cause vibration.

Quality control
Throughout the manufacturing process, quality control checks are performed to verify that the camshaft meets the required specifications and tolerances. This is crucial to ensuring the camshaft's reliability and optimal engine performance.

Assembly
Once the camshaft is complete and has passed all quality checks, it is ready for installation in the engine. It will be positioned in the engine block and connected to the crankshaft via timing gears, belts, or chains. The camshaft's timing to the crankshaft is carefully set to achieve the desired engine performance.

Operating Conditions of Camshaft

The cam bearing is subjected to periodic shock loads. The contact stress between the cam and the tappet is very high, and the relative sliding speed is also very high, so the wear of the cam working surface is more serious. In response to this situation, the camshaft journal and cam working surface should have high dimensional accuracy, small surface roughness and sufficient rigidity, as well as high wear resistance and good lubrication.
Camshafts are usually forged from high-quality carbon steel or alloy steel, and can also be cast with alloy cast iron or ductile iron. The journal and cam working surface are polished after heat treatment.

How to Adjust the Camshaft Correctly

First, check whether the timing adjustment hole is on the left or right side of the engine. Open the large screw cover and use the sleeve to rotate the crankshaft. There is also a small screw cover on it, which is used to align the t point. Rotate the crankshaft, look in from the small screw cap, slow down when you see two vertical channels on the ci motor (note) and immediately see another vertical channel and an f, (for the ignition advance) don't worry, in turn, see t a finger apart, then stop. Align the vertical channel on the left of the t with the small cut on the box. Remove the mouth of the left cylinder and try it with a screwdriver to see if the piston is at top dead center. If there is no accident, it should be there, and then the piston is at the top dead center, and then the camshaft is installed.

Reinstall the camshaft and see what marks are on the chainring on the camshaft. It should have ex and in. Ex means exhaust and in means intake. The upper intake camshaft is horizontal with the in side rail, and the top exhaust camshaft is horizontal with the ex side rail.

First turn the piston of the left cylinder to the top dead center, and hold the screwdriver vertically to prevent it from accidentally jamming. The camshaft shoulder of one cylinder intake is placed nearly horizontally towards the carburetor. The exhaust camshaft shoulders are placed almost horizontally towards the exhaust port. One cylinder is right for the other, because it's all on the same shaft. At this time, the intake and exhaust valves should be closed, and the camshaft should not feel the pressure valve. When tightening, the bolts should be tightened evenly. This installation may require 1 to 2 teeth, don't be afraid, test the car first.

The Relationship Between Crankshaft and Camshaft

(1) The upper camshaft is placed on the cylinder head, which is commonly used in passenger car engines. Main advantages: Less moving parts, short transmission chain from camshaft to valve, high rigidity of the whole mechanism, suitable for high-speed engines. The main disadvantage is that the transmission distance between the camshaft and the crankshaft is long, and the toothed belt drive or chain drive is generally used.

(2) The central camshaft is located on the upper part of the cylinder block. Compared with the lower camshaft type: The push rod is reduced (or the push rod is shorter), thereby reducing the reciprocating mass of the valve train, increasing the rigidity of the mechanism, and more suitable for high-speed engines.

(3) The lower camshaft is located in the crankcase. Main advantage: The camshaft is closer to the crankshaft and is generally driven by a pair of gears. The main disadvantage is that there are many moving parts, the transmission chain from the camshaft to the valve is long, and the rigidity of the whole mechanism is poor, and it is mostly used in low-speed engines.

FAQ

Q: Why is it called S-cam brakes?

A: Air pressure pushes the rod out, moving the slack adjuster, thus twisting the brake camshaft. This turns the S-cam (it is shaped like the letter “S”). The S-cam forces the brake shoes away from one another and presses them against the inside of the brake drum.

Q: What connects the brake chamber to the S-cam?

A: The air pushes against the diaphragm and the push rod. The push rod is connected by a clevis and pin to a crank arm type lever called a 'slack adjuster'. This converts the pushing motion of the push rod from the brake chamber to a twisting motion of the brake camshaft and 'S' cams.

Q: What is a brake S-cam?

A: The “S” cam brake is the most common type of foundation brake used on commercial vehicles with air brake systems. This is a drum brake that uses air brake chambers and linkage to press the brake shoes against the surface of the brake drum.

Q: Is there a left and right S-cam?

A: To ensure you've got the correct camshaft, turn the S groove to face you. If the Left hand will fit in the groove, you're holding a left hand camshaft. If replacing a camshaft on the passenger side, you'll replace it with a Right Hand Camshaft.

Q: How to tell if AS cam is bad?

A: Some of the most common symptoms of a bad camshaft include a lit check engine light, power loss, and backfire in the intake manifold. The most effective solution for repairing a bad camshaft is replacing it entirely.

Q: Which way do S-cam seals go?

A: NOTE: Cam seals MUST be installed in the brake spider with the steel shoulder oriented toward the wheel, and the rubber wiper oriented toward the center of the vehicle.

Q: Where should grease be applied on an S-cam brake system?

A: At each service, squeeze grease into the brake slack adjusters, S-camshaft bearings and anchor bolts. Before greasing, clean the nipple heads carefully to prevent any dirt getting into the bearings.

Q: What is the function of the brake camshaft?

A: The brake camshaft is a part of the brake linkage for heavy duty truck air brakes. The camshaft is the component responsible for spreading the brake shoes apart. In air brake systems, the brake chamber expands and the operating rod pushes on the (brake) slack adjuster.

Q: What causes brakes to cam over?

A: It means either your brake shoes are so far worn that you automatic slack adjusters turned the s cam to the point the rollers fell off the tip and returned to the lowest position (the problem with that is now that it has cammed over it cannot return and you have no brake on that axle.)

Q: What connects the brake chamber and the S-cam?

A: In an S-cam brake system, the pushrod is connected to a lever called a brake adjuster (also called a slack adjuster). When actuated by air pressure in the brake chamber, the pushrod forces the brake adjuster outward.

Q: How to measure S-cam brakes?

A: First, you'll need to measure the length of the camshaft by measuring from just below the cam head until the beginning of the lock ring groove.
Next, determine the style of the head comparing it to the styles found here and determining the head width.

Q: Can an S-cam be used on either side?

A: Right- and left-hand S-cams can be used on either side of a vehicle. The S-cam is a component of the drum brake system in vehicles. It is responsible for applying pressure to the brake shoes, which in turn press against the brake drum to slow down or stop the vehicle.

Q: Why is it called an S-cam?

A: Explanation: S-cam drum brakes are called an S-cam because the shape of the cam resembles the letter 'S'. The S-cam is a mechanism that helps in the operation of the brake shoe in drum brakes.

Q: What are the components of the S-cam brake?

A: "S" cam brake components refer to the parts of a specific type of drum brake system commonly used in heavy-duty vehicles. In this system, the key components are camshafts and brake shoes.

Q: What is an S-cam on a trailer?

A: An S-cam is part of a braking system used in heavy vehicles such as trucks and wheeled machinery. It consists of a shaft, usually around 4 to 25 inches long, turned at one end by means of an air-powered brake booster and lever with an S-shaped cam at the wheel end.

Q: How long do camshafts last?

A: Camshafts should last the lifespan of the engine – at least 186,000 – 248,000 miles. Failing camshafts can lead to extensive and expensive engine damage which is why they need to be replaced immediately after failure symptoms have been identified.

Q: Where do most camshafts fail?

A: Valve train components and camshafts rely on a film of lubricating oil to operate correctly. When this film isn't present due to lack of oil, incorrect oil, oil breakdown/contamination, or overheating – failures occur. Blown head gaskets are a primary contributor to camshaft failure.

Q: When should a camshaft be replaced?

A: In the event that there is any visible wear, change the cam. Most of the wear isn't even visible so if you can see it, it's worse than you think. A worn cam can rob as much as 20 percent of your horsepower, not to mention significantly decreasing your engine's fuel economy.

Q: How often should you grease s-cams?

A: All S-cam tubes should be lubricated at 25,000 mile, re- gardless of brake brand. Fully lubricated brake S-cam tubes ensure that moisture and contaminants do not enter the cam tube, potentially causing corrosion, slow return, and seal damage.

Q: How do S-cam brakes work?

A: The S-cam forces the brake shoes away from one another and presses them against the inside of the brake drum. When you release the brake pedal, the S-cam rotates back and a spring pulls the brake shoes away from the drum, letting the wheels roll freely again.

We're well-known as one of the leading brake s camshaft manufacturers and suppliers in China. Please feel free to wholesale bulk high quality brake s camshaft at competitive price from our factory. For customized service, contact us now.

fa20 camshaft, Brake Camshaft For YORK, Brake Camshaft For STR