Timing Belt Vs Timing Chain

The flow of air through your engine is controlled by a series of mechanisms that are driven by either a timing belt or timing chain, but what is the difference between them?

Timing Chain:

Timing chains were used exclusively throughout the early ages of the automotive industry due to their ruggedness, durability and simplicity. Most timing chains are roller chains made out of steel, similar to the type you would find in a bicycle or motorcycle. Steel’s hardness, tensile strength, and modulus of elasticity makes it a perfect material for a long lasting timing drive system in an engine.

In an engine application the chains require a lubrication system to reduce wear and friction from the metal to metal contact between the rollers and the sprockets. The rollers themselves also need the lubrication to perform their key function (roll) as the chain rotates around various sprockets. This helps to reduce friction and increase the efficiency of the drive system. Typically, a roller chain has an efficiency of around 97% which means that if it takes 9.7 horsepower to turn the camshaft(s) in your engine at a certain speed, then it will actually take 10 horsepower because some of the power is absorbed within the timing chain due to friction in the rollers.

Timing Chain Advantages:

  • Lower cost – the camshaft sprockets for timing chains and the actual chains are easier to manufacture than timing belt components which means lower costs for the car company and you
  • Longer life – they typically last at least 150,000 miles because of the properties of steel and the continuous lubrication system which means less maintenance for your vehicle compared to a timing belt

Timing Chain Disadvantages:

  • Weight – timing chains are heavier than timing belts because of their all steel construction which requires more power from the engine to overcome inertial forces
  • More expensive replacement – generally, a timing chain is more expensive to replace because the whole chain system is encased by a timing chain cover and valve cover to contain the lubrication system.
  • Noise – chains are always louder than belts because of the metal to metal contact

Timing Belt:

Timing belts were introduced to increase the efficiency of engines and reduce noise. It consists of steel wire-reinforced rubber that has cogs (semi-cylinder teeth) that fit in the corresponding grooves of the camshaft and timing pulleys. The rubber belts can naturally flex around the pulleys as it rotates and the rubber to metal contact requires no lubrication system. Torque is transferred through the cogs to eliminate slippage and minimize friction. Timing belts are also very efficient at power transmission – up to 98%. Their main downfall is longevity.

Timing Belt Advantages:

  • Quiet operation – no mechanical linkages that are constantly bending and no metal to metal contact
  • Lightweight – less inertial forces means more overall engine power and responsiveness
  • Lower timing belt replacement costs – valve cover removal is not necessary and the pulleys are easier to access

Timing Belt Disadvantages:

  • Longevity/Reliability – they only last up to 100,000 miles because rubber wears faster than steel. The belts are also more susceptible to breakage which may lead to extremely expensive engine repairs.
  • Durability – the rubber in the timing belts is more sensitive to weather conditions and will not last as long in extreme conditions.

Timing Belt Replacement: Symptoms That Indicate That You Need One

The timing belt of a car’s engine is a very important part because it serves as a connection between that camshaft and crankshaft. Because of this, it controls and monitors the opening and closing activities of the valves of the car’s engine. This shows that getting a timing belt replacement when needed is vital. The timing belt ensures that the engine works properly and smoothly. Cars that have four stroke engines are designed in a way so that their engine valves open and close during each revolution of the crankshaft. This serves as another proof that timing belt replacement needs to be done as soon as possible if it’s needed.

Symptoms That Indicate That Timing Belt Replacement Needs To Be Done

In general, a timing belt last for a long period of time. However, over a certain period of time, you need to get it replaced. This leads us to the question “How will I know that my car needs a replacement?” There are certain symptoms that will tell you that you need to get one done for your car. These are actually very easy to recognize. Let’s take a look at them:

Difficult Ignition

Most cars that have a good mileage suffer from ignition problems when their belt gets damaged. Oftentimes, the car won’t start quickly and you need to hold the key for a long time just so you can start your vehicle.

Shaking Engine

You will feel your car shaking because it’s belt has already gone wrong. The timing with the pistons and valves are set accurately. So, when it gets damaged, the timing can go wrong causing the car to tremble while it’s operating.

Excessive Firing

Excessive firing, going over the amount of exhaust will cause problems to your car later on. Damage to the belt is one of the reasons why this happens.

Engine Overheating And Leaking

Hot weather conditions can sometimes cause damage to the belts. Thus causes the car’s engine to overheat and to start leaking.

Once you confirm that your car needs a belt replacement, you need to take it to a reputable auto repair shop. You should also get a good idea as to how much this service costs. On average, the price for this service usually ranges from $300 to $800. In some cases, cars need maintenance repairs for other parts which causes the overall cost of the repair service to increase.

How to Maintain and Replace Your Car’s Timing Belt

Belts in the car play such an important role but they are rarely considered whenever it is time for maintenance and repairs. Still, paying attention to the belts can ensure the smooth functioning of all the vehicle parts and your safety on the road.

What is a Timing Belt?

The timing belt is the piece that synchronises the functioning of valves and pistons. The camshaft and the crankshaft are connected by it. The lack of perfect synchronisation will make it impossible for the car engine to run smoothly. The timing belt is the one piece responsible for achieving the goal.

The lack of tension will speed up its wearing out. Excessive tightness will damage bearings. When maintaining and repairing your car’s timing belt, you will have to achieve precision for optimal functioning of all parts.

Checking the tension is a monthly necessity. A car timing belt kit can be purchased and used for that purpose. It will save you both time and the money that you will otherwise have to spend on a professional service. When inspecting, make sure that the engine is not running. There is a serious risk of accidents in such instances.

Equipment Needed for Maintenance and Repairs

If you are interested in doing vehicle repairs on your own, you will have to invest in the right kind of equipment. The most commonly needed pieces for the maintenance include:

· Torque wrench

· A good screwdrivers set

· Socket set

· Combination wrenches

· Jack and jack stands

· Drain pan

Bolts, pins and obviously a new timing belt will be needed, whenever you have to replace the old piece. Keep in mind that the equipment and the specifics of the procedure will very often depend on the vehicle kind and the model. There is no universal solution and you should learn more about the specifics of your car and its engine functioning.

Causes of Problems and What to Look for

If you are used to working on your own car, you have certainly seen the timing belt. Do you, however, know what to look for in order to determine whether it is in good condition or in need of replacement?

Cracks, excessive slack and shredding are all causes of concern. If you notice such signs of aging, you should consider replacing the old piece.

The engine itself gets quite heated during functioning, which will cause natural damage to the timing belt. Other factors that will affect its condition and speed up the damage include oil leaks that could cause belt corrosion, infrequent driving and excessively dry climates that will damage the material that the belt is made of.

You will have to replace the timing belt at least once during your ownership of the vehicle. Routine inspections of its condition will give you an idea about when that might be. Having a car timing belt kit ready beforehand, will only be a convenience for you when the time comes. Taking a look on a monthly basis will prevent you from experiencing problems on the road, while you are away from home.

Avoid Used Cars Not Having Certified Mileage; A Broken Timing Belt Can Flatten Your Wallet

Premature failure of a rubber timing belt can easily cost two or three thousand dollars of repairs, possibly including a new engine. Therefore knowing the true mileage of a used car is imperative. Off lease Cars having 4 or 6 cyl. engines may have rubber timing belts and should be avoided.

Be warned

Five years ago an international oil company survey found that 50% of off-lease cars had their odometers illegally turned back and suggested consumers avoid buying off-lease (used) cars, or leasing used cars having uncertain mileage. If the cars really had 50,000 miles, and the odometer read 30,000, then the timing belts would fail long before the new owners expected them to fail.

What is an “interference engine”?

Rubber timing belts are usually used in “interference” engines in which the
valves open further and project further into the combustion chamber than in a “free-running” engine. This allows outside air at atmospheric pressure to flow faster into the combustion chamber through the larger valve openings, allowing the engine to inhale more air, be smaller and still create as much power while reducing its manufactured cost and guaranteeing future repair business for the dealer.

If a rubber timing belt breaks while engine is running, some of the valves stuck in their
open position will smash into the top of the pistons, thereby breaking or
irreversibly damaging one or the other or both.

How to find out if the engine is an “interference engine”.

The salesperson may not know; ask the Service technician. Better yet, go on any search engine and type in “interference engine list” because asking the Dealer’s service technician may not be reliable. If he says it does not, have the Dealer’s Sales Manager (not the salesperson) say so on the purchase order and personally sign and thereby guarantee his assertion. For recommended replacement mileage of rubber timing belts, connect on the Internet to Gates Rubber Company, a worldwide manufacturer of such belts. On its web site, click on Replacement parts/automotive. Look for “timing belt replacement Guide”.

Get a written guarantee to cover premature failure of the car engine’s timing belt.

Because most rubber timing belts on car engines should be replaced at 60,000 to
70,000 miles to avoid the engine self destructing, insist on a written guarantee from the seller to guarantee replacing the timing belt at no charge if it fails within another 20,000 miles. If the seller won’t guarantee it then he’s admitting that the mileage may be inaccurate and by implication may have been turned back. Consider a compromise, such as a $300 price reduction on the vehicle. If not acceptable, walk away.

Replacement cost

Simply replacing a rubber timing belt even at recommended mileage can cost $400 + dollars. Before buying any car, especially 4-cylinder foreign cars, or even a 6-cyl. BMW, be aware of the unavoidable cost of $400-$800 to replace a rubber timing belt at recommended intervals based on mileage or car age.

That’s assuming the timing belt didn’t break. If it breaks (always while the engine is running) then internal engine damage will take place catastrophically. If a timing belt on an interference engine is not replaced at recommended intervals, the repair cost when the belt breaks could increase to $3,000 to $5,000 to replace the entire engine. The sales person will invariably not mention that an interference engine powers the vehicle and may not even know what one is.

The sad part of this problem is that it is not possible to detect timing belt wear without substantially tearing down the engine. The timing belt is literally a “sleeping time bomb”.

Therefore, always buy the cars with “free-running” engines…