A car engine consists of many components that are used to transmit energy. Some auto parts have a more prominent role in the engine’s working, while others are connected components to enhance efficiency. The camshaft is an essential component; without it, the 4-stroke engine wouldn’t work.
Let’s go through the comprehensive guide on the camshaft mechanism, its parts, and what happens when the camshaft goes bad.
What Is the Function of a Camshaft?
Camshaft’s primary role is to control the opening and closing of the engine’s valves, ensuring the precise timing and duration of these events. The crankshaft rotates the camshaft into a reciprocating motion to open and close the valves. That said, it actuates the engine’s valves.
The camshaft functions through a series of lobes or cams positioned along its length. As the camshaft rotates, the lobes push against various engine valve actuation mechanisms (such as rocker arms, followers, or hydraulic lifters). It opens the valve and closes at specific intervals.
The timing of valve opening and closing is essential for the four-stroke engine. For instance, longer valve duration allows efficient intake and exhaust processes and improves engine breathing, power delivery and torque characteristics.
Driving Mechanism of the Camshaft
The driving mechanism of the camshaft depends on the engine design and can vary. The following are the driving mechanisms of the camshaft:
Gear Drive
Several engines use a gear drive mechanism to drive the camshaft. In this setup, the camshaft connects to the crankshaft through gears.
These gears have specific tooth profiles to maintain precise timing between the crankshaft and camshaft rotation. As the crankshaft turns, the gears transfer the rotational motion to the camshaft, controlling the valve operation.
Chain Drive
A chain around sprockets connects the camshaft and crankshaft in the engines that use a chain and sprocket arrangement. The chain’s movement transfers the rotation from the crankshaft to the camshaft, ensuring proper valve timing.
Belt Drive
In many modern engines, a car timing belt or chain drives the camshaft. This belt or chain connects to the camshaft to convert the motion of the reciprocating piston into a rotary motion.
The timing belt/chain is routed around various gears or sprockets, connecting the crankshaft and camshaft. It ensures synchronisation between the two shafts’ rotation. As the crankshaft rotates, it drives the camshaft through the timing belt or chain, causing the camshaft lobes to actuate the valves.
Parts of a Camshaft
A camshaft consists of several distinct parts that work together to perform this function. Here are the main components of a camshaft:
- Cam lobes
- Journal bearings
- Timing gear
- Camshaft position sensor (CMP sensor)
- Camshaft bearings
- Thrust plate
- Camshaft pulley
Different Types of Camshafts
Camshafts come in various types, each designed to optimise engine performance based on specific requirements. Here are some different types of camshafts:
Flat Tappet Cam
It is the most basic and commonly used type of camshaft. It has a flat surface on which the lifters or tappets ride. These camshafts require regular maintenance, including periodic replacement of the lifters and camshaft due to wear.
Roller Cam
Roller camshafts feature roller bearings on the cam lobes, allowing for reduced friction and wear. Compared to flat-tappet camshafts, they are more durable and can handle higher valve lift and RPM. Roller camshafts are common in high-performance engines.
Hydraulic Camshaft
These use hydraulic lifters that adjust the valve lash, ensuring precise valve operation and reduced maintenance. They are quieter compared to solid camshafts and provide smooth valve action. Modern passenger vehicles usually use these hydraulic camshafts.
Solid Camshaft
Solid camshafts have mechanical lifters with no hydraulic adjustment. They require regular adjustment of the valve lash to maintain proper valve clearance. Solid camshafts are found in high-performance engines where precise valve control is essential.
Mushroom Camshaft
Mushroom camshafts have a unique design with a rounded, mushroom-shaped cam lobe profile. They are commonly used in high-performance engines and offer improved valve lift and duration compared to traditional camshafts.
Variable Valve Timing (VVT) Camshaft
VVT camshafts can vary the timing of the valve lift events. They can adjust the valve timing based on engine speed and load conditions, improving performance, fuel efficiency, and emissions. Modern engines come with variable valve timing engine technology. Some examples of VVT engines are:
Symptoms of a Bad Camshaft
A bad camshaft can cause various symptoms in an engine. Here are some common signs that may indicate a problem with the camshaft:
Engine Misfires
A faulty camshaft can lead to irregular or incomplete combustion in one or more cylinders, causing car engine misfires. You may experience a rough running engine, hesitation, or loss of power.
Poor Performance
A damaged camshaft can affect the engine’s performance, causing a decrease in power, acceleration, and overall efficiency. The engine may feel sluggish and unresponsive.
Rough Idle
If the camshaft lobes are worn or damaged, it can disrupt the engine performance at idle. You may notice a rough or lumpy idle, with the engine shaking or vibrating excessively. It may also be a reason for the car jerking at an idle position.
Decreased Fuel Efficiency
A faulty camshaft disrupts the proper timing and duration of valve opening and closing, leading to inefficient combustion. It decreases fuel efficiency, causing the car to consume more fuel than usual.
Stalling or Difficulty Starting
A severely damaged camshaft can affect the engine’s ability to start or keep running. The engine may stall frequently, especially at idle, or have difficulty starting altogether. It may also be a malfunctioning camshaft position sensor symptom.
Loud Ticking or Knocking Noise
Worn or damaged camshaft lobes can cause the lifters or valve components to make noise. You may hear a loud ticking or knocking sound from the engine, especially during acceleration. Besides, other problems can also cause noises in the engine or car. You can use the five senses to identify car problems, such as noises or smells.
Check Engine Light
If the camshaft position sensor detects irregularities in the camshaft’s rotation or timing, it may trigger the Check Engine warning light on the dashboard. In this case, the engine control module (ECM) stores specific engine diagnostic trouble codes related to the camshaft position or timing.
Therefore, using an onboard diagnostic (OBD) scanner can help identify the malfunctioning code and fix the problem.
Replacement Cost of the Camshafts
The replacement cost of the camshafts depends upon the damage. Some components of the camshaft can be replaced at a minimal price. However, complete camshaft damage can cost up to AED 3,000 to 5,000 in the UAE.
That wraps the comprehensive information about the camshafts. When you buy a used car in the UAE, ensure checking all the components for the effective and efficient performance of the vehicle.
Stay connected with the dubizzle autos blog to learn more about different car parts and what causes their malfunction.
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