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      Camshaft Types and Components

      When it comes to the smooth functioning and performance of an internal combustion engine, the camshaft is one of the most vital components. To ensure that the former does its job properly, the latter has to work seamlessly with the crankshaft. Because of this, there is no room for error when machining a camshaft. That is particularly true in the case of performance vehicles.

      Below is a concise guide to what camshafts are, how they operate, the different kinds of camshafts on the market, and their pros and cons.

      Overview of the Camshaft?

      In an internal combustion engine, the camshaft is that part of the valve train that is responsible for regulating fuel input and getting rid of fumes. It typically comes in the form of a cylindrical rod or shaft with egg-shaped cams that rotate to generate power.

      Camshafts can be made of a variety of metals and are normally situated above the cylinder at the top of the car’s engine. Once you’ve located it, you should be able to see the timing chain and belt connecting it to the crankshaft.

      One of the most important jobs of the camshaft is to drive the opening and closing of the valves (both intake and exhaust). This is why it plays such an important role in the engine’s performance, particularly when the car is accelerating.

      • The typical camshaft consists of three parts:

      • The driver member that is called the cam.
      • The follower, i.e. the member that's being driven
      • The supporting member, which essentially consists of a frame-like structure that supports both the driver and the follower.

      Depending on how they are configured, camshafts are able to generate both high-end and low-end torque. They are also useful to enhance the dynamic capabilities of the valve-actuating mechanism.

      Different Types Of Camshafts

      Let us now take a closer look at the various types of camshafts and their pros and cons:

      Flat Tappet Camshafts

      This type of camshaft is among the oldest technologies in motoring history. They have been the industry standard for more than 40 years and still enjoy solid support from motoring enthusiasts. Their popularity and success can be ascribed to the fact that they are relatively cheap, generate a good amount of power, and do not need a lot of routine maintenance. Flat tappet camshafts have to be combined with hydraulic lifters since the latter uses a spring-loaded, oil-damped plunger to automatically help support valve lash.

       If one looks at the lobe interface, a flat tappet might at first seem to actually be flat. On closer inspection, you will, however, notice that the flat tappet’s geometry is much more complex than that. A flat tappet lifter’s face has a relatively big curvature radius, while a taper keeps the lobe grounded. This enables the tappet to skate during rotation, instead of scrubbing across the lobe as many people think.

      Roller Camshafts

      As you probably deduced from the name, hydraulic roller camshafts make use of a tappet combined with a roller wheel that serves as the cam follower. It basically just rolls across the camshaft lobe. While these are undeniably more pricey than their flat tappet counterparts, they also generate more power.

      Apart from reducing friction, it is also possible with roller cams to manufacture a steeper ramp into the cam, which boosts duration. And unlike the vital break-in process needed in the case of flat tappet camshafts, roller models do not need break-in. On top of that, they are also more durable than their competitors.

      The good news is that, when it comes to price, mechanical roller camshafts (which are regarded as the industry standard when it comes to power generation) nowadays compete quite favorably with their hydraulic roller counterparts. They also offer longer duration and steeper cam ramps than the latter. However, like many other performance parts, they require regular maintenance to keep them working properly.

      Different Camshaft Configurations

      There are quite a few camshaft arrangements but the following are the most common:

      OVH - OverHead Valve

      In a OHV engine the camshaft is installed inside the engine block and valves are operated through lifters, pushrods and rocker arms (an OHV engine also known as a "Pushrod" engine).

      OHC - OverHead Camshaft

      OCH or SOHC Cam

      In a SOHC engine the camshaft is installed in the cylinder head and valves are operated either by the rocker arms or directly through the lifters

      DOHC- Dual Overhead Camshaft

      DOHC CAM

      A DOHC setup is used in most of newer cars. Since it's possible to install multiple valves per cylinder and place intake valves on the opposite side from exhaust vales, a DOHC engine can "breathe" better, meaning that it can produce more horsepower with smaller engine volume.

      Single Overhead Camshaft

      This is the oldest type of camshaft on the market. As the name indicates, it features a single camshaft for every head. Most SOHC engines have two valves per cylinder. In these engines, the timing belt or chain has to be examined and adjusted on a regular basis because if it is misaligned or damaged it could break, in the process causing major damage.

      Double Overhead Camshaft

      These are popularly known as twin-cam engines. In this case, there are two camshafts for every bank. Engines with more than four valves for every cylinder often feature double overhead camshafts.

      One of the biggest benefits of a DOHC is that it has the ability to significantly boost engine power. The reason for that is quite simple: with a double overhead camshaft, you can use more valves (both intake and exhaust). This in turn means bigger openings for gas flow.

      Pushrod Camshaft

      Also often referred to as OHV or overhead valve camshafts, these engines also feature valves in the engine’s head, on top of the cylinder. In contrast to SOHC and DOHC engines, however, where the camshaft is located in the cylinder head, in this case, the camshaft is right inside the engine block.

      In pushrod camshaft engines there is a gear chain that drives the camshaft. This makes the whole configuration more reliable and less likely to experience problems. The downside is that, to a certain extent, an OHV camshaft limits the engine’s speed potential.

      HYDRAULIC VERSUS SOLID

      When considering different types of camshafts, an important consideration is whether to choose one with a hydraulic or solid lifter. Both flat tappet and roller shafts are widely available for either hydraulic or solid lifter configurations.

      Hydraulic camshafts have been the industry standard for large engines for many years. These shafts auto-adjust to ensure there’s no valve lash. The result is a long-lasting, quiet valve train requiring no adjustment or maintenance.

      In a performance vehicle, the same hydraulic mechanism that works so well in a production car could, however, places a limitation on power, and might become a source of instability. Reasons for this include high spring loads, deflection, and flex in the valve train. While a solid lifter could experience the same problems, it doesn’t have a hydraulic mechanism that could be a source of control loss.

      In an engine that has been tuned for high performance, a solid camshaft might therefore be a better choice.