The intake and exhaust valves are opened and closed by the camshaft, a spinning shaft with blades or cams. Therefore, a malfunction in this component—which typically results from inadequate lubrication—is critical.
An automobile engine functions due to the interaction of numerous components, each of which is essential for achieving peak performance. In that way, the camshaft is significant to the combustion process.
But what exactly is a camshaft, and what does it do? The cams or blades are part of a rod or rotating shaft.
The intake and exhaust valves of the cylinders, where the entire process of burning the fuel-air mixture to provide the energy that moves the vehicle, are designed to open and close as the shaft spins periodically.
To maximize combustion and prevent malfunctions or misalignments, valve actuation must be as swift and accurate as possible.
A spinning shaft with separate cams for the intake and exhaust valves is known as a double camshaft and is occasionally employed.
What is the camshaft’s mechanism?
The crankshaft, connected to it by a timing belt or chain, powers the camshaft. This enables it to assist the gasoline pump and aid in oil distribution throughout the engine.
When we turn the ignition key in the car, an electrical impulse is created that causes the crankshaft to rotate.
As a result, the pistons inside the cylinders are pulled and pushed by the connecting rods, compressing the air-fuel combination and producing the spark that lights the spark plugs in the combustion chamber (provided we are talking about a gasoline engine, of course).
The intake valves open to let the air-fuel mixture pass, and the exhaust valves open to allow the extraction of the gases produced by combustion at the end of the cycle, simultaneously as the camshaft begins rotating as it is connected to the crankshaft through the timing belt or chain.
Various camshaft types
There are different sorts of camshafts depending on where they are located in the engine:
SV type
Inside the engine, the valves are positioned laterally about the cylinders. The compression chamber for this system must be more significant than usual, and there isn’t enough room for the valve heads to be as big as they may be.
OHV type
In this scenario, the cylinder head houses the valves while the camshaft is positioned in the bottom portion of the engine block.
Additionally, a more direct system of sprockets or a short-travel chain is employed to link to the crankshaft instead of a traditional chain or timing belt.
Although the system has more components and can only turn the engine at a limited number of revolutions, this implies that maintenance is essentially nonexistent.
Lastly, the engine’s temperature contributes to the tappet clearance being higher than usual.
OHC type
The camshaft in an OHC-type engine is situated in the cylinder head next to the valves, making it the most prevalent engine type in use today.
This technology reduces the number of components needed to connect the camshaft to the intake and exhaust valves, which leads to quicker operation and a faster engine speed.
But since the timing belt or chain must be longer, complexity, cost, and wear and tear will increase. The performance is better, though.
The latter system comes in two variations: SOHC and DOHC. The DOHC uses a double camshaft for the intake and exhaust valves, whereas the former uses a single camshaft for all the valves.
What are some reasons a camshaft might fail?
As we said at the beginning of this article, mechanical issues with the camshaft typically result from inadequate lubrication, which has the unintended consequence of causing premature wear of the bearings and bearings.
Additionally, if a camshaft component is destroyed, we will need to replace the whole part, one of the most expensive breakdowns a car user can experience.
Additionally, a bearing may stop distributing lubricant properly, causing the engine housing to become loose. This is possible.
How can we determine whether our car might be experiencing camshaft failure? The following are some indications that can warn us and, as a result, avert a more significant financial outlay:
The car won’t start
When a car doesn’t start, little can be done because the camshaft has seized and needs to be changed.
Loss of power
The shaft support may have seized, the cams may be broken or loose, or both.
A loud squeaking sound
It indicates that the camshaft may be about to seize up, so we must examine the supports.
Rattling
If there is rattling, the gears may be disengaged, or the bushings and supports may be too worn.
FreeValve
In 2015, the Swedish company Koenigsegg unveiled the “FreeValve” system, which does away with mechanical timing, including a camshaft and a timing chain or belt.
Instead, it uses an electronic system developed in partnership with the Chinese manufacturer Qoros, which substitutes an electric, hydraulic, and pneumatic actuator for the camshaft to provide autonomous and as-needed control of the opening and closing of the intake and exhaust valves.
Along with removing the need for maintenance and timing kit replacement, this method also enables increased power and decreased usage.
Although this technology is not currently in a production-ready state, Koenigsegg and Qoros intend to start incorporating it into their upcoming street vehicles.
