What is a Camshaft in Cars: A Detailed Guideline You Need To Know

What is a Camshaft? To understand what is camshaft, it is a rotating shaft that converts rotary motion into reciprocating motion. It is used in internal combustion engines to open and close the intake and exhaust valves.

A camshaft is a metal horizontal bar. It is made of iron or steel. It sits on top of the cylinders above the engine. The camshaft mixes air with fuel. It moves them out of the combustion structure. It transforms rotational motion into linear motion.

Parts of A Camshaft

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

Cam: 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.

The driveshaft enables the camshaft's movement. It links via a belt to the crankshaft. Or it 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.

The chain sprocket connects to the camshaft. It also helps keep timing in sync. This includes the camshaft and crankshaft. The timing belt assists with this.

Working Principles of A Camshaft

The camshaft opens and closes valves. It controls intake and exhaust valves. This happens at proper times. The camshaft connects to the crankshaft with a belt. The crankshaft's speed is twice the camshaft's. A four-stroke engine has four categories. These are intake, compression, ignition, and exhaust.

In the intake stroke, the valve opens. Air and fuel enter the cylinder for combustion. The crank rotates, moving the piston up. Both valves are closed. This is the compression stroke. The spark plug projects crank motion. This happens before the top dead center (BTDC). The piston reaches top dead center (TDC). Then, thermal expansion and combustion occur.

At high speeds, the flame fires across the piston. Thermal energy works on the piston. This acts on the connecting rod. It also impacts the crankshaft journal. This converts linear motion to rotational motion. When the crankshaft returns, the piston moves up. This expels hot, fuel-mixed air. It goes through the exhaust valve. Cam lobe actions cause this valve movement. It works against the pushrod and rocker arm. It also affects the lifter and valve stem.

Types Of Camshafts In Car Engines

There are different types of camshafts each categorized based on the following:

• Based on lifters used by the camshafts
  Based on the camshaft’s shape

Based On Lifters Used By The Camshafts

In car engines, there are two major types of camshafts based on the lifters used; they include:

• Flat-tappet Camshafts

• This camshaft is a very old technology that has been in the automobile industry for years. They are, however, very affordable, produce a high amount of power, and do not wear out over time, which means there is no need for special maintenance. In addition, this type of camshaft must work with hydraulic lifters or followers. It also makes use of an oil-coated plunger to protect the valves.

  In terms of appearance, the flat tappet camshafts look flat at first glance, but with further inspection, their complex geometry becomes noticeable. Moreover, the face of the hydraulic lifters on the flat tappet has a big circular cross-section. On the other hand, the taper makes sure the lobe is well confined. This makes the tappet run well during rotation.

• Roller Camshafts

• As the name implies, this type of camshaft uses a roller wheel (cam follower) and a tappet for its operations. It literally only rolls across the lobe of the camshaft. Roller camshafts are more expensive than flat tappets, but they also produce more power and last longer.

  In addition, roller camshafts can reduce friction and produce a more curved ramp in the camshaft, which increases the time frame. In contrast to flat-tappet camshafts that require break-in processes, roller camshafts do not need break-in.

  When it comes to prices, mechanical camshafts are cheaper than hydraulic roller camshafts, and they also produce quite a bit of power, which makes the industry consider them a standard power generator. But its disadvantage is that it requires constant maintenance.

Based On the Camshaft’s Shape

• Cylindrical Camshafts
• From its name, it is cylindrical in shape, and it is also known as a barrel or drum cam. Its surface has a groove cut into it, which the cam follower makes use of for motion.
• Radical Camshafts
  
• This can also be known as a “disc clam.” It has an axis that is directly normal to the follower’s movement path. Also, radical Camshafts possess a shapeless contour plate that transforms the motion of the cam into that of the cam follower.
• Conjugate Camshafts
  
• A conjugate camshaft comprises two rollers that connect the cam follower or driver together. These rollers restrict the motion of other parts, which results in the elimination of noise for quiet machine processes. They are most suitable in areas that require the silent operation of the camshaft.
• Spherical Camshafts
• They are spherical in shape. A groove is located on the curved design. In this type of camshaft, the speed of the cam follower is perpendicular to the rotational part of the spherical cam.
• Wedge camshafts
• Their endpoints are very sharp, along with a wide basement. However, in wedge cams, the driver moves in a sliding manner in relation to the camshaft.

Failure of  Camshaft and Possible Solutions

Camshafts have downsides, like other machine parts. A worn camshaft can damage other car parts. These include the cylinder head and crankshaft. Here are ways to recognize camshaft failures:

Flashing check engine light

• This is a type of warning light that comes on when the car’s technology discovers a problem that might lead to serious damage or misfire. The check engine light serves as a diagnostic tool for checking the problems in the engine of a vehicle.

Noisy Tapping Sounds

• This is one of the most significant symptoms of a bad camshaft. The valve train starts producing strange sounds when it starts failing. However, the strange sounds are mostly because of reduced efficiency in hydraulic lifters than problems associated with the cam lobes.

Metal Particles in the Engine Oil

• A failed camshaft can lead to the spread of metal debris across the car’s engine. Most of the time, the metal debris is not visible on the dipstick, but after pouring the oil out, there may be metal particles or debris.

Cylinder Misfire

• This causes a car with a worn camshaft to fail due to inefficiency in the engine. The common signs of a cylinder misfire are sudden loss of power in the car, shaking in a forceful manner, and sometimes, overconsumption of fuel can be a result of a cylinder misfire.

Increased Gas Emissions

• When a camshaft is damaged, it results in misfires in the car’s engine, which also lead to an increase in emissions.

Visible Signs of Damage

• Worn lobes and scored journals are all visible signs of failed conditions that have spoiled the camshaft.

Solutions

A damaged camshaft is fixable especially when you know how a camshaft work. However, it is always better to consult a professional for appropriate repairs. This is a result of detecting the problem and providing the best solutions to fix the camshaft’s issues. However, based on the damages caused by wear and tear, the following are possible solutions:

Get a New Camshaft

• Aside from knowing how the camshaft and crankshaft function, the best solution when you have a damaged camshaft is to get a new one. Getting a new camshaft will remove the tendency of past problems. However, it can be quite expensive to buy a new camshaft. You should consider getting a new one when you have a broken lobe, the wear on the lobe is excessive, the case hardening depth is too small, or the camshaft has a bent shape.

Have Your Damaged Engine Camshaft Properly Machined

• Having your damaged engine camshaft properly machined is a far less expensive solution compared to the first. However, the degree of damage can determine whether the method is viable and the price of remanufacturing. Proper rebuilding is possible for camshafts with worn lobes.

Weld the Damaged Camshaft

• Welding is suitable for rebuilding a camshaft with wear (although not too much). It involves adding a harder material to fill in the worn part and grinding it to meet the proper specifications.

What is a Camshaft in Cars: A Detailed Guideline You Need To Know