As you can imagine, the timing of the inlet and exhaust valve has to be very accurate and precise for proper functioning of the engine. Even a slight delay in the opening or closing of either of these valves can result in failure of the engine, if not worse. Today, we are going to understand the timing belt and how it functions inside a standard internal combustion engine. If you want to know more about the timing belt, stick until the end of our guide where we will talk about the symptoms of a bad timing belt and how you can replace it yourself. Before we dive deep into the topic, let’s get familiar with the timing belt itself and see how it works inside an engine.
Timing Belt: How Does it Work?
The timing belt, as the name suggests, is a simple belt drive that transfers the motion of the crankshaft to the valves to adjust the timing of their rotation. The belt controls both, the piston as well as the valve to ensure proper working of the engine at all times. As for the construction, the belt is quite simple as it is made up of rubber with an internal teeth-like structure that locks onto the teeth of a gear. As you may already know, the crankshaft and valves are the components that must always be synchronized with precise delay in rotation to achieve perfect inlet and exhaust in the engine. When the engine is activated, it pulls the piston downwards creating a vacuum in the combustion chamber which is then filled with a mixture of air and fuel. For that, the inlet valve must open at the exact moment when the piston has reached its lowest position. After that, the piston is pushed upwards to compress the mixture and decrease its ignition point as low as the temperature of a spark. At this moment, both of the valves must be closed to avoid loss of pressure. Once the air-fuel mixture is compressed, the spark plug generates a spark which results in a controlled explosion of the mixture, creating excessive pressure and pushing the piston downwards. This chemical reaction leaves a combination of carbon and other gases that should be removed from the engine. At this point, the exhaust valve opens and the residue gas is pushed out. For that, the exhaust valve has to open at the precise moment or the pressure level inside the combustion engine might increase above the design limit. Now that you know how important the functioning of the inlet and exhaust valve is, let’s take a look at how the timing belt manages to keep the function in perfect harmony. As you already know, the timing belt is directly connected to the crankshaft as well as the camshaft which controls the engine valves. Thus, the motion of the crankshaft is directly connected to the valves, keeping them in sync with the process. Therefore, a timing belt must operate with optimal performance to guarantee the proper functioning of the engine.
How To Identify a Bad Timing Belt?
Now that you know how important the timing belt is for the overall operation of the engine, it may not be too difficult to realize what would happen if the belt does not work properly. First of all, it would mismatch the functioning of the valves which will severely degrade the efficiency of your engine. Either the air-fuel mixture intake won’t be in the right proportion, or the exhaust valve will fail to create an opening for residue gases to leave the chamber. Further delay in the timing might also cause excessive pressure increase in the chamber which can result in unfortunate incidents. However, such situations can be easily avoided if you can detect the signs of a bad timing belt early on. Generally, the timing belt does not fail or break easily. So if the belt is damaged, you will start to notice a few anomalies in your engine’s performance. Once you start noticing these factors frequently, you can take a look at the timing belt and assess the condition beforehand. So if you do not wish to find yourself stranded with an out-of-order engine in the middle of nowhere, make sure you keep an eye out for the following symptoms of a bad timing belt.
1. Improper Idling of The Engine
When you let go of the accelerator of your car, the engine does not stop right away. Instead, it keeps on running at a low speed which is called “idling”. Even at the time of idling, the timing belt keeps on transferring the motion of the crankshaft to the valves, maintaining a slow but steady movement of the camshaft. If the timing belt has started to wear, it will start slipping in-between the driving and driven gears, causing a slight mismatch. You will get an idea about it if you notice a non-uniform exhaust sound from your car at the time of idling. If the belt starts to slip further, the engine will not be able to maintain the idling process and will shut off after a certain period of time.
2. Misfire of The Engine
The firing rate of the engine can also be affected due to a bad timing belt. It gets instantly affected if the belt teeth are slipping from the gear teeth. The slippage causes the inlet/exhaust valves to open and close at incorrect timing which generates misfire. If the exhaust valve opens too quickly, the air-fuel mixture might escape the chamber before it is combusted, causing a shorter power cycle. On the other hand, an excessive inlet of the air-fuel mixture will cause improper combustion, causing excessive pressure buildup inside the engine. If your engine is misfiring, it means that the belt has worn out a lot and might need a replacement very soon. Failing that, it might cause irreversible damage inside the combustion chamber, affecting all included components such as the valves, piston, piston rings or even the connecting rod of the crankshaft.
3. Unusual Smoke Coming Out of Exhaust
An unusually high amount of smoke coming out of your exhaust pipe or the engine itself is never a good sign. Apart from various other anomalies, it can also be caused due to the inefficiency of a bad timing belt. There are rarely any instances where the smoke is actually water vapor. The majority of the time, it indicates a critical problem with the overall functioning of the engine. If the smoke is caused by a bad timing belt, you will definitely notice a strong smell of fuel which indicates improper combustion. You can also check the color of the smoke to be sure. If it is darker than usual, it means that the engine is burning an excessive amount of fuel. As you can imagine, it will bring down the mileage of your car quite low. This is caused by a worn-out timing belt as it misses the closing time of the inlet valve, allowing too much air-fuel mixture into the combustion chamber. And with the excessive fuel inside the chamber, the combustion is also louder and the residue gases are also denser. Thus, you see a denser exhaust coming out of your tailpipe.
4. Reduction in Oil Pressure Level
As you may already know, the combustion chamber of the engine has a certain amount of oil inside it. This oil is called engine oil and it is introduced to maintain lubrication between the piston and the cylinder. The oil also maintains the temperature levels inside the chamber given that there is constant combustion occurring inside. For optimal performance of the engine, the engine oil has a certain pressure level which should be maintained at all costs. However, it changes if the timing belt is not performing well. Due to non-uniform valve timing, there are improper combustion levels on the inside which causes wear and tear of the internal parts. Generally, it breaks the camshaft and the pieces and it mixes with the engine. Due to that, the engine oil pressure level drops. Most cars have a built-in sensor that alerts you when the oil pressure level drops significantly. If you are also noticing low engine oil pressure, it may indicate problems with the timing belt.
5. Broken Piston or Inlet/Exhaust Valve
As we mentioned before, the timing belt can also cause wear and tear of the piston or any other critical part inside the engine. It can also be considered as the worse symptom as it indicates irreversible damage of the timing belt. In the majority of cases, it causes severe damage to the piston or valves, creating the need for a replacement. If the problem continues, the timing belt might break. This will result in the crankshaft operating completely out-of-sync and the valves might get permanently damaged.
How Much Does Replacing a Timing Belt Costs?
Now that you understand the severity of problems caused by a simple timing belt, you must know how important it is to replace the damaged unit as early as possible. But, you might be wondering whether it’s gonna cost you a fortune to get the job done. Well, while it may not cost a lot, the cost of the job depends upon the type of vehicle you own. The larger the vehicle is, the harder it is to reach the engine and replace the timing belt. Thus, the cost of replacing a timing belt on heavy loading vehicles is certainly higher than a commercial car. For economical cars that operate on a compact engine, the labor cost should be quite cheap. But, as the job for such cars is so easy, you can even get it done yourself without needing any professional help. In the next section of our guide, we will tell you how to replace the timing belt by following a simple set of instructions.
When Should You Replace The Timing Belt?
Before we discuss how to replace the timing belt, you need to know when you actually have to do it. Generally, your automobile manufacturer already has a schedule where there is a maintenance procedure that includes the replacement of the timing belt. You can get more info about the same from the manufacturer of your car. According to standards, the replacement period is scheduled between 70000 to 100000 miles. But, the above-mentioned schedule might not be the same for everyone. If you own an off-road car, then you might have to replace the timing belt much sooner. Also, if you need to drive through a relatively bad road on a daily basis, the timing belt will get damaged quickly due to the effect of external factors. In such a case, you need to monitor your vehicle carefully and schedule a replacement as soon as you notice any of the symptoms we have mentioned above.
How To Replace a Timing Belt?
Coming to the most important part of the guide, let us discuss how to replace the timing belt properly. Make sure you follow the instructions, especially if this is the first time you are accessing the internal parts of an engine. We will still recommend getting the job done by a professional and observing the procedure so that you can do that yourself next time it is required. Here is how you can replace the timing belt:
First of all, you need to get access to the timing belt. As this is an internal part of the engine, it won’t be easy to do so. To get access to a timing belt, remove the accessories covering the engine. Then, remove the engine cover which will expose the internal components of the engine. Now, you should closely observe the parts and check which parts need a replacement. Sometimes, it might be the pulley or the camshaft which might get damaged and cause problems with the timing belt. If you are certain that the timing belt is damaged, remove it from the engine. After that, you can install the new timing belt inside the engine. Installing the new timing belt might be a little tricky and you may have to apply a little tension on the belt to fit it over the pulley. Once the timing belt is installed, close the engine and put all the accessories back in their place. When you test the engine, you shall not notice any irregularities in the valve timing, nor should there be misfiring of the engine.
Conclusion
An engine is quite an intricate part of your car which includes a lot of additional components such as the timing belt, chain drive, or working fluid. In this guide, we have covered the timing belt of an engine and explained what it is and how it works inside an engine. You will also find detailed information on bad timing belt symptoms and what you should do in case you notice any or all of these anomalies. If you are unsure about the information present in our guide, you can reach us via the comment section and bring your query to us and we will definitely try to resolve it as soon as possible. Comment * Name * Email * Website
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