Thursday, April 12, 2012

Timing Belt and Timing Chain


Timing belts, (also known as toothednotchcog, or synchronous belts) are a positive transfer belt and can track relative movement. These belts have teeth that fit into a matching toothed pulley. When correctly tensioned, they have no slippage, run at constant speed, and are often used to transfer direct motion for indexing or timing purposes (hence their name). They are often used in lieu of chains or gears, so there is less noise and a lubrication bath is not necessary. Camshafts of automobiles, miniature timing systems, and stepper motors often utilize these belts. Timing belts need the least tension of all belts, and are among the most efficient. They can bear up to 200 hp (150 kW) at speeds of 16,000 ft/min.



Timing belts with a helical offset tooth design are available. The helical offset tooth design forms a chevron pattern and causes the teeth to engage progressively. The chevron pattern design is self-aligning. The chevron pattern design does not make the noise that some timing belts make at certain speeds, and is more efficient at transferring power (up to 98%).
Disadvantages include a relatively high purchase cost, the need for specially fabricated toothed pulleys, less protection from overloading and jamming, and the lack of clutch action.

Timing Belt vs Timing Chain
Some people quite proud to have a timing chain vehicle without knowing that most of the advantages are on the timing belt side. Thus, I'm going to share some facts of the timing belt and timing chain itself. Timing chain technology on a car is 10-20 years ahead of the timing belt but after doing some survey, i found that it is better to have timing belt compare to chain. The reason why car manufacturer like Toyota and Nissan build such a car with timing chain is to prevent the timing belt from breaks because timing chain use a more reliable metal instead of fiber material. The metal chain will last longer than the timing belt and it is the only advantage of timing chain over timing belt.


Nowadays, most of the material for the fiber has been improved and can withstand any pressure and tension for longer times up to 100 km of trip. The cost timing belt is cheaper depending on the models of the car. While timing chain is designed to fit forever on the engine due to its reliability. Only when your chain sounds noisy which will require you to replace the new one and the cost is expensive definitely. 
In many cases, a timing belt makes more sense than a timing chain. For all its advantages, a timing chain is noisier, less efficient, and more expensive than a timing belt.

Timing Belt Features

  1. Much quiter than timing chain
  2. Timing belt just only need light support rather than timing chain
  3. Timing belt do not require silencer as timing chain does.
  4. Engine can be to high RPM without having to worry about excessive momentum chain.
  5. Must be changed every 70,000 to 100,000 km with the Tensionerand water pump (if driven by a timing belt).
  6. Does not require lubrication such as timing chain
  7. Timing belt will stretch a little but not so as to cause timing drift.
  8. Timing belts reduce the energy loss due to friction of the belt because it has more    contact   area.
  9.  Reduce the energy loss due to vibration (basically a belt equipped with shock absorber).
  10.  Damage does not interfere with timing belt drive system and cause little damage and danger from timing chain.
  11. Timing belt replacement easier than timing chain.
  12. Only a small amount of energy required to move the lightweight belt against the heavier chain while reducing fuel consumption.
Timing Chain Features

  1. Timing Chain needs tensioner when used with SOHC* engine /DOHC** with a silencer, but most of them combine with both at once. So two tensioners used silencer
  2. Timing chain does not need to be changed, such as timing belts (some can be used up to 400 000 km), it can only be adjusted when there is loss of power or out of the engine noise (some manufacturers recommend inspections every 100 000 km)
  3. Chain is usually more severe and require a strong support structure.In some cases, the chain stretched when it comes a time and make quick tensioner hairy. The sound engine will also be uncertain.
  4. Timing chain is usually reliable and require regular inspectionsMostmodern ECU timing chain capable of finding problems that increase the reliability of the entire system.
  5. Timing chain is usually placed in the engine cover and constantly lubricated.
  6. Timing chain tidak akan menegang tetapi akan haus pada satu ketika.
so choose which is best for you..
Either timing belt which should be changed every 70,000 to 100,000 km and energy saving or timing chain that requires only a regular inspection and needs to be changed when there's a  noise out of the engine.


*SOHC - Single OverHead Cam.
**DOHC - Double/Dual OverHead Cam.

1 comment:

Driveparts Direct said...

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