What is Timing System and Timing Belt?
The timing belt, also known as the camshaft belt and timing belt, is one of the most critical parts, which is vital for the engine safety and performance of our vehicles.
The timing belt transmits the motion it receives from the crankshaft to the camshaft, enabling the valves to open and close, and is also responsible for the engine coolant. In most of today’s vehicles, the timing belt moves the water pump, allowing the engine coolant (antifreeze) to circulate within the cooling system. In summary, the timing belt provides the movement needed for the rotation of both the camshaft and the circulation water pump. However, in order to ensure this movement, it can proceed in a certain order.
So, in what order does it work while providing this movement?
How the timing belt and shafts are aligned is determined by the car manufacturers. The crankshaft and camshaft gears are adjusted according to this alignment determined by the automobile manufacturers, and then the timing belt is attached to the notches on these shafts. As it turns out, fitting the timing belt to the specified alignment ensures that the valves are opened and closed at the right time so that the engine can timing correctly.
What Are Timing System Parts?
Timing Belt: The timing belt obtained from a rubber material is the part that transmits the movement it receives from the crankshaft to the camshaft.
Tension Ball (Tensioner Bearing): It is used to stretch the timing belt to maintain the correct alignment between the crankshaft and the camshaft.
Circulation Water Pump: Since vehicle engine units are exposed to excessive heat, it needs heat balance. The circulation water pump also provides the heat balance required by the engine units by allowing the engine coolant (antifreeze) to circulate within the cooling system.
What is Timing Chain?
There is also a chain version of the timing system, which varies according to the vehicle brand and model. The timing chain (timing chain) connects the camshaft sprocket with the crankshaft sprocket. It has a very durable hardened metal structure as the motor moves fast and rapidly during operation. The timing chain is located behind the front engine cover. The circulation water pump in the timing system is also responsible for the engine coolant while performing its function of the timing chain. It can also include the operation of the part called the timing chain, the oil pump, into its role.
If we examine the connection between the timing chain and the oil pump; The timing chain needs engine oil to perform its function, and this need is met by the oil pump that pumps the engine oil in the crankcase with the action of the camshaft. The oil pump has other important tasks, apart from reducing the friction and minimizing the heat by pumping oil to the regions in need. Another of these tasks is to analyze the return of the oil pumped. So this means that; The oil pump will filter the dirt generated during the return of the pumped oil and minimize the dirt as much as possible in the oil it will pump again. Another important mission undertaken by the oil pump is to keep the engine performance stable for a long time. So as we will understand briefly; The timing chain, which plays a major role in the healthy and performance of the engine, and the oil pump are two very critical parts for the timing chain to function properly.
When and How often should the timing belt and timing chain be replaced?
We mentioned in detail that the timing belt and timing chain are important for engine life and performance. It is also necessary to pay attention to the times and intervals of absolute change of such critical parts. First, let’s consider the change intervals of the timing belt in terms of time and mileage. The reason why two different types of questions are asked about timing replacement is due to the fact that timing belt life is determined in two different ways. This means that; The timing belt has an expiration date according to both the duration of use and the mileage used. According to the reference values recommended by automobile manufacturers, the timing belt replacement time and change mileage vary on the basis of vehicle brand and model. However, if we give an average reference year and kilometer, we can specify it every 4 years or every 60 thousand – 100 thousand kilometers. Whichever of these two criteria occurred first, it should be based on. In other words, even if your vehicle has not reached the mileage of the timing belt replacement and your vehicle has not detected any obvious damage to the timing belt, if 4 years have passed, the timing belt must be replaced.
Now, if we examine the same situation for the timing chain, the replacement time and change mileage will be even longer. The reason for this is that it is more durable since it is made of hardened metal material compared to the timing belt made of rubber material. The timing chain can be used up to 150-160 thousand kilometers without having to change it. There is no year-based change criterion as in the timing belt, but it should change when the timing chain makes a noise close to the mileage.
What happens if the timing belt and chain break?
The timing belt / timing chain, which is the heart of the engine, needs to act in a certain order in order to timing the engine correctly, but if it fails to fulfill this task in the event of a malfunction in the timing system, it will cause serious damage to the engine. If the timing belt / timing chain breaks, the camshaft, crankshaft and valves will be damaged simultaneously and engine bankruptcy will occur.
In case of timing belt break;
It will not be able to transfer the movement from the crankshaft to the camshaft and consequently it will not be able to open and close the valves.
Since the engine cannot timing correctly, the valves that should be closed remain open and the piston hits the open valves.
As a result of the piston hitting the open valves, the valves are bent and the pistons are damaged.
Difficulties occur in all parts affected by valves and pistons.
There is a big noise caused by the breakage of the timing and the engine can not perform its duty in any way by stopping.
What Should Be Done When Timing Belt and Timing Chain Break?
If the timing belt or timing chain breaks while driving, it is necessary to pull the car to a suitable place and park it. Because, as seen in FIGURE 4, when the timing belt breaks, the valves remain open and the pistons hit the valves and cause the valves to bend, so that the engine operates in this state will cause greater damage to the engine. If you think there is a problem with your vehicle, but you are not sure whether your timing belt or timing chain is broken, pull your vehicle to a suitable place again, turn off the ignition and open the hood and check. When you open the hood, if you can see the ends of the timing belt or the parts of the broken tire, you can see that your timing belt has broken. At the same time, the engine sounds very different and loud. Apart from all these, the fact that black smoke comes out from the exhaust may also indicate the breaking of the timing belt or timing chain.
Points to Consider While Replacing Timing Belt and Chain?
For timing belt and timing chain replacement, which are vital in terms of engine health and performance, first of all, the instructions for the year of change and mileage described in the heading “When and How Often should be replaced?” In addition, other issues to be considered during both timing belt and timing chain replacement; It is the replacement of other parts associated with these two critical parts. Now let me examine what are the connected parts that need to change.
What Are The Parts That Should Be Changed When Replacing The Timing Belt?
Circulation Water Pump: We learned that one of the tasks undertaken by the timing belt is that it enables the engine coolant (antifreeze) to circulate within the cooling system by moving the circulation water pump. Due to this function of the timing belt, it is necessary to change the absolute circulation water pump, if necessary, during the replacement. Because when the timing change of the vehicle comes in years or kilometers, the circulation water pump will also have done the same year and kilometer.
In other words, if you do not change the circulation water pump in order to reduce the costs by replacing the timing belt, you will have to pay labor costs for the removal of the timing assembly again due to the deformation of the circulation water pump shortly after waiting for the next timing belt maintenance. Moreover, if the defective circulating water pump is not replaced, sufficient amount of antifreeze will not be able to circulate in the cooling system and the possibility of the engine overheating will increase. Apart from this, water leakage may occur in the seals and gaskets in the circulation water pump, thus the vehicle may decrease water. For all these reasons, you should have the condition of the water pump checked in vehicle maintenance without skipping over and replace it if necessary.
Engine Coolant (Antifreeze): In case of a change in the circulation water pump, the antifreeze in the vehicle will be discharged accordingly, so the absolute antifreeze changes according to the liter that the vehicle will take.
Charging Belt: In other words, this part, also known as V-Belt or fan belt; It is the part that transfers the power needed by the water pump, alternator and ventilator to the engine power. The charging belt (V belt & fan belt) transmits this power from the camshaft by means of various gears by the rotation of the wheels on the parts such as the water pump, the dynamo and the fan. V belt replacement period can be changed at intervals determined by automobile manufacturers on the basis of brand and model. If we give mileage for V belt replacement, we can say an average of 60 thousand kilometers. Other factors that will trigger the V-belt (Charge belt & fan belt) replacement are; Noise from the charging strap is the formation of cracks on the strap and the strap loosens. If any of these reasons are observed during the timing change, it must be changed without waiting for the change kilometer. If the V-belt should be replaced but not replaced; The V belt will break, causing the circulation of the water pump to stop, and thus the alternator that produces electricity with water will not be able to fulfill its function.
With the alternator being dysfunctional, the vehicle will run for a while with the energy in the battery charge, but you will encounter a problem such as staying on the road because the battery charge will run out in a short time.
Charging Belt Tension Ball (V Belt Tension Ball): It is the part that keeps the belts in the vehicle taut. While the serrated tension ball is used due to the toothed timing belt in the timing system, a flat tension ball is used because the V-belt has a flat structure. If a charge belt replacement is required while the timing system is being renewed, the charge belt tensioner ball must be replaced accordingly. If the v-belt tensioning ball, which keeps the charging belt (v-belt & fan belt) taut due to its duty, is not replaced, the ball that has completed its service life is disintegrated and the belt becomes unable to rotate. The air conditioning compressor connected to the charge belt, the alternator, the circulation pump and if your vehicle has power steering, the steering pump will be disabled due to the fact that the charging belt does not rotate.
Tension Ball (Tensioner Bearing): The tension balls that keep the timing belt angularly taut must be changed during the timing belt replacement. Just like the V-belt tensioner ball, if the change of the tensioner bearing is foreseen and not changed, the tensioner roller will disintegrate, causing the timing belt to loosen and then the belt to break. We learned that the negativity to be experienced in case of timing belt breakage is engine bankruptcy. Therefore, these balls, which keep the belts tight, must be replaced.
What Are The Parts That Should Be Changed When Replacing The Timing Chain?
As with the timing belt, the water pump must be replaced in the timing chain. At the same time, the oil pump part must be replaced in vehicles whose oil pump is connected to the timing chain. We talked about the close relationship of the timing chain with the oil pump that pumps the engine oil it needs to fulfill its function. In addition, we explained in detail the other important functions of the oil pump part in our “What is Timing Chain” title. Apart from all these, the oil pump can also be called the timing chain cover.
Based on all this information, we can say that; The oil pump will do the same distance as much as the distance traveled by the timing chain. In other words, if the timing chain is used for 150 thousand kilometers, the oil pump will also make 150 thousand kilometers, so the oil pump part must also be changed during the timing chain replacement. Otherwise, if only the timing chain changes but the oil pump does not change, the oil pump will make 2 times the mileage until the next timing chain and the oil pump will stop lubricating after about 20 thousand-30 thousand kilometers. If the oil pump stops lubricating, the problem that will be experienced in the scenario will cause the engine to lack oil and, in industrial terms, the engine will lead to bearing winding, that is engine bankruptcy. If the oil pump is changed, the oil pump seal should also be changed accordingly. Because if the old oil pump gasket is installed on the new oil pump, oil leakage problem will occur and oil loss will be seen in the vehicle.
Depending on the oil pump change, oil pump seal change, external engine oil and oil filter must also be changed. Because, due to its oil filter function, it transfers the engine oil in the crankcase by filtering it into the engine block. The oil pump is filtered by the oil filter and pumped the engine oil sent to the engine block in a pressurized manner, allowing the pistons in the engine block to work without difficulty. As can be seen from this relationship, the new engine oil and the new oil filter must also be changed to the new oil pump.
There are other parts that may require replacement during timing chain maintenance; such as front crank seal, circulation water pump, antifreeze (engine coolant) charging belt, charging belt ball. The Front Crank seal is located inside the engine behind the crankshaft pulley and is located just below the outward projection of the crankshaft. The task of this seal, just like the oil pump seal, helps the oil stay in the system by preventing the leakage of engine oil, which is vital for engine health. The front crank seal is actually a rubber seal in form and contains a spring inside. If engine oil does not leak out, it is caused by the spring stretching of the tire. As the vehicles travel with kilometers, the form of the springs deforms and loosens and becomes unable to tighten the tire. Subsequently, the engine will suffer great damage with the engine running without oil due to the inevitable last oil leakage problem. Therefore, during timing chain maintenance, if it is expected to change, it must be replaced with a new one.
In timing belt maintenance, we mentioned why the replacement of the circulation water pump, antifreeze (engine coolant), charging belt and charging belt balls is needed. For the same reasons, if necessary, the circulation water pump, antifreeze, charging belt and charging belt ball must be replaced in the timing chain.