Advanced Inspection Technologies introduces a new line of flexible micro borescopes that are incredibly thin. The new micro borescopes will be able to inspect the interior of castings, machined parts, turbine components and other parts that were previously impossible to inspect. In addition to the availability of small diameters of 0.35 to 3.8 mm the new micro borescopes are flexible. Rigid micro borescopes are limited by the ability to only inspect in areas with a straight pathway for access. The new flexible micro borescopes from AIT allow inspectors to snake through passage ways and turn corners to view areas that were previously inaccessible.

"The new micro borescopes are so thin that they are nearly the size of a human hair," said Paul Fitzgerald, President and CEO of Advanced Inspection Technologies. A Human Hair is only 0.1 mm in diameter, so you would only need three and a half to equal the size of the smallest micro borescope.

Micro borescopes are commonly used to examine inside the smallest bores, tubes, channels and accesses on a variety of castings, machined parts, turbine blades or vanes and other manufacture components where the strictest quality control is essential. Micro borescopes view into these tight spaces to look for debris, burrs, cracking, corrosion, blockage and a variety of other defects. The new small diameter flexible micro borescopes from AIT allow inspectors to examine areas that were impossible to access in the past.

The new flexible micro borescopes are capable of the highest resolution images possible. The new super thin flexible borescopes are constructed of the most advanced quartz image bundle. The quartz image bundle allows for incredibly high resolution in the small diameter scopes. The number of pixels of the new flexible micro borescopes can be as high as 30,000 depending on the diameter.

The new flexible micro borescopes from AIT are compatible with standard light sources and video systems. This allows manufacturers that have existing borescope cameras and light sources to use the new small diameter flexible micro borescopes with their existing equipment.

Headquartered in Melbourne, Florida, AIT is the industry leader in the sales and rental of Remote Visual Inspection equipment such as borescopes, videoscopes, fiberscopes, thermal cameras, pipe inspection cameras and foreign object retrieval tools. AIT’s products have been used to improve the inspection process in all industries where image quality, safety, security and accuracy are of the highest concern, such as aviation, electric power generation, petrochemical, manufacturing, predictive maintenance and infrastructure.

» Read More...

RF welding is a basic technology, and the basic devices necessary to affect such a weld have not changed since the inception of the process. Today, as in 1942, we need a generator to provide RF, a transmission line to transfer power, a press to apply force and an electrode in the desired geometric pattern to be welded.

The terms "Radio Frequency (RF) Welding or Sealing" are often used interchangeably with "High Frequency (HF) or dielectric welding or sealing." When matter is brought into contact with an electromagnetic field, some portion of the electromagnetic field will go through a change of energy state. As a result, it will be converted to heat and dissipated within the contacted matter. The degree to which this con-version will occur, or the efficiency of this conversion of energy state is dependent on the atomic and molecular structure of the matter, the frequency of the electromagnetic field, and the field potential (Volt-age/cm). The term dielectric heating correctly describes this phenomenon at any frequency while RF or HF heating describes the process over the lim-ited frequency range from 1 to 200 megacycles/sec (megahertz/sec).

The area where most of the technological changes have taken place is in the components from which the individual devices are constructed. Solid state components have replaced mercury vapor rectifier tubes. Digital timers have replaced industrial timers. Programmable Logic Controllers (PLC) have replaced relay logic.

When a PLC is used with linear and optical encodes, precise control can be achieved over the various functions that determine the specific characteristics of the weld. Using these types of devices it is possible to monitor and control functions of time, pressure, current and voltage and their profiles.

When modern material handling systems are used in conjunction with these devices, high speed automatic production systems can be built. Many hundreds of such systems are in use throughout the U.S. These systems manufacture a wide variety of products for the automotive, stationary products, and medical industries.

The continuing stream of new RF responsive materials being brought to the market further impact the industry. In addition, additives and RF responsive adhesives are continually being developed for specialized applications. It is now possible to bond materials that in the past were considered unsuitable for the RF process. These changes are opening up a new range of products that can now be manufactured by this time proven technology. This will have a great effect in the medical industry, as it tries to eliminate the use of vinyl.

Both electron beam and laser welding, when initially discovered, were thought to be possible replacement technologies. However, these technologies have been found to be more applicable for spot or seam welding of metals or other rigid materials where welding times are measured in minutes and hours. In RF welded products, welding times are measured in seconds or fractions thereof. Guideline believes the likelihood of these becoming competing technologies is very low. In Guideline's opinion there is nothing on the horizon that will replace RF welding in the next 5 to 10 years. Its place will be as secure as it is today, not only as the economically preferred way to weld certain materials, but in many cases the only feasible method.

» Read More...

RF welding is a basic technology, and the basic devices necessary to affect such a weld have not changed since the inception of the process. Today, as in 1942, we need a generator to provide RF, a transmission line to transfer power, a press to apply force and an electrode in the desired geometric pattern to be welded.

The terms "Radio Frequency (RF) Welding or Sealing" are often used interchangeably with "High Frequency (HF) or dielectric welding or sealing." When matter is brought into contact with an electromagnetic field, some portion of the electromagnetic field will go through a change of energy state. As a result, it will be converted to heat and dissipated within the contacted matter. The degree to which this con-version will occur, or the efficiency of this conversion of energy state is dependent on the atomic and molecular structure of the matter, the frequency of the electromagnetic field, and the field potential (Volt-age/cm). The term dielectric heating correctly describes this phenomenon at any frequency while RF or HF heating describes the process over the lim-ited frequency range from 1 to 200 megacycles/sec (megahertz/sec).

The area where most of the technological changes have taken place is in the components from which the individual devices are constructed. Solid state components have replaced mercury vapor rectifier tubes. Digital timers have replaced industrial timers. Programmable Logic Controllers (PLC) have replaced relay logic.

When a PLC is used with linear and optical encodes, precise control can be achieved over the various functions that determine the specific characteristics of the weld. Using these types of devices it is possible to monitor and control functions of time, pressure, current and voltage and their profiles.

When modern material handling systems are used in conjunction with these devices, high speed automatic production systems can be built. Many hundreds of such systems are in use throughout the U.S. These systems manufacture a wide variety of products for the automotive, stationary products, and medical industries.

The continuing stream of new RF responsive materials being brought to the market further impact the industry. In addition, additives and RF responsive adhesives are continually being developed for specialized applications. It is now possible to bond materials that in the past were considered unsuitable for the RF process. These changes are opening up a new range of products that can now be manufactured by this time proven technology. This will have a great effect in the medical industry, as it tries to eliminate the use of vinyl.

Both electron beam and laser welding, when initially discovered, were thought to be possible replacement technologies. However, these technologies have been found to be more applicable for spot or seam welding of metals or other rigid materials where welding times are measured in minutes and hours. In RF welded products, welding times are measured in seconds or fractions thereof. Guideline believes the likelihood of these becoming competing technologies is very low. In Guideline's opinion there is nothing on the horizon that will replace RF welding in the next 5 to 10 years. Its place will be as secure as it is today, not only as the economically preferred way to weld certain materials, but in many cases the only feasible method.

» Read More...

Over the years, a number of people have expressed an interest in careers in underwater welding, but were unsure how to get started. Welders, students, divers, and other interested men and women have contacted the American Welding Society (AWS) for guidance. In order to help those prospective underwater welder-divers, the D3B Subcommittee on Underwater Welding has provided answers for eight commonly asked questions.

This article was prepared by the American Welding Society's D3B Subcommittee on Underwater Welding.

The answer to the questions presented in the article are not intended as recommended practice nor as endorsement of any definitive means of pursuing underwater welding as an occupation. Rather, the aim is to provide enough useful information to assist those interested, as well as define some of the mis-conceptions associated with the trade. For additional information and/or a need for specialized training, the subcommittee recommends ANSI/AWS D3.6, Specification for Underwater Welding, as a comprehensive reference and resource for industry-accepted practice.

1. What skills are prerequisite to entering the field of underwater welding?
The skills suggested for entering the field of underwater welding can best be defined by the following typical description of a welder-diver from the AWS D3.6 Standard and the qualifications generally recognized.

"Welder-diver: A certified welder who is also a commercial diver, capable of performing tasks associated with commercial subsea work, weld setup and preparation, and who has the ability to weld in accordance with the AWS D3.6, Specification for Underwater Welding Specification for Underwater Welding (i.e., wet or dry), and other weld-related activities (see item 7.0)."

By description, an experienced welder-diver must possess: commercial diving skills (i.e., be familiar with the use of specialized commercial diving equipment, have an understanding of diving physiology, diving safety, rigging, the underwater environment, communication, etc.); weld setup and preparation skills (i.e., the ability to perform tasks typically assigned to a fitter or rigger, such as materials alignment and materials preparation including beveling, stripping of concrete, fitting a steel patch or repair plate, etc.,); and the ability to certify to a required underwater weld procedure.

2. I am a certified surface welder, what other training do I need to qualify as a welder-diver?
The majority of work performed by an average welder-diver does not involve the welding operation itself, but rather executing the tasks that lead up to and follow the actual welding activities. Except under special circumstances, a welder-diver in most cases must posses both certified welder skills and commercial diving skills.

It is suggested that if you have no prior commercial diving experience you should attend one of the recognized commercial diving schools. Commercial dive schools vary insofar as duration of course, cost, etc., however, most offer a basic commercial diver certificate upon successful completion. The candidate may be required to pass a diving physical prior to school acceptance and in some cases a written exam. It is suggested that a dive physical be taken regardless, to avoid going through the expense of training only to later find you have a disability that prevents your entering the profession. A listing of U.S. commercial diving schools accredited by the Association of Commercial Diving Educators can be obtained by contacting: Association of Diving Contractors International (ADC), 1960 FM 1960 W., Suite 202, Houston, TX 77069; (281) 893-8388; FAX (281) 893-5118.

As a general rule, candidates seeking underwater welding as a career will decide whether or not they are comfortable with their career choice after completing basic commercial dive training.

Once that basic commercial diver training is completed, it is common practice to apply for employment at one of many commercial diving companies that offer underwater welding as a service. An interview with the company of your choice is recommended to express your career goals in underwater welding and past welding experience. Expect to begin your career as a diver tender (apprentice diver) initially. As a diver tender you will gain valuable practical experience while learning the trade.

Before performing on-the-job underwater welding, most diving contractors will require that you achieve sufficient skill in wet and/or dry underwater welding to pass qualification tests and be certified in accordance with the requirements of ANSI/AWS D3.6, Specification for Underwater Welding. The time required to advance to welder-diver varies subject to supply and demand of welder-diver personnel, skill, motivation, experience and other factors. Most commercial diving firms have their own policies and procedures regarding this matter.

3. I am already a certified diver, what other training do I need to qualify as a welder-diver?
The welding processes, classes of weld and qualification tests associated with underwater welding are described in ANSI/AWS D3.6. We recommend the specification as a reference for weld procedure and welder qualification. It is also a good source of other helpful information.

If you are already certified as a "commercial diver" and work for a company that offers underwater welding services, it is recommended that you communicate to your company your career objectives and ask what welder skills they are looking for. If you are unemployed or do not work for a company that offers underwater welding services, it is suggested that you communicate with the commercial diving firm of your choice that offers underwater welding services and train to its requirements.

If you are certified as a "scuba diver" (e.g., NAUI, PADI, etc.), it is suggested that you attend a commercial diving school. Sport dive training does not include the safe use of commercial diving equipment, offshore commercial work environment/safety, and other education as recommended by the Association of Diving Contractors Consensus Standards for Commercial Diving Operations.

Underwater welding is a skill you also have to master once you obtain the basic commercial diving skills required. Again, it is suggested that you communicate with the commercial diving firm of your choice that offers underwater welding services, and train to its requirements. Each commercial diving firm has its own policies and procedures regarding this matter.

4. What are the age limitations of a welder-diver?
There is no age restriction on commercial welder-divers. There are, however, physical requirements. It is recommended and generally required that all commercial divers pass an annual dive physical. ADC has an industry-accepted dive physical format that is used by many of its members in the United States and other countries (e.g., some companies may have other requirements, subject to the regulations of the country where they are located, etc.).

The commercial diving profession is physical demanding. It is rare to see an active commercial welder-diver over the age of 50.

5. What is the availability of work for an entry-level welder-diver?
This is a difficult question to answer. It is more appropriate to ask the company with whom you seek and/or gain employment. There are a number of diving procedures that serve the various types of underwater industrial requirements, each of which have different underwater welding needs. Like many professions, work availability is always subject to: supply vs. demand, the economics of a given industry, whether you are free to relocate outside your place of residence (including overseas), what other related skills you have in addition to diving and welding, etc. A number of welder-divers have established a reputation of high-quality workmanship and/or productivity and are asked for by name. The company you choose to work for is also a factor.

The answer to the question is that there is work available for entry-level welder-divers; however, the amount of work available is subject to the aforementioned variables.

6. What salary can I expect to make as a welder-diver?
An average salary vs. grade index would be interesting to look at if there were one, but the truth of the matter is that salaries for welder-divers cover a wide range. We know some welder-divers earn $15,000 per year while others earn in excess of $100,000. Because the majority of welder-divers are paid on a project-by-project basis, salaries are subject to the same variables as work availability. In addition, other factors such as depth, dive method and diving environment affect pay rates. The company with whom you gain employment should be able to tell you the salary range you can expect to earn.

7. What other skills are recommended to supplement my qualifications as a welder-diver?
The commercial diving and underwater welding industry is as diverse as the customers it serves. The welder-diver qualifications required for a given assignment vary from project to project. Ideally, a diving contractor would like its welder-divers to be "a jack of all trades and a master of them all!" Practically speaking, possessing the skills that are common to underwater welding operations, in addition to welding and diving, are recommended. Primarily these skills are: underwater cutting (oxyfuel, abrasive water jet, mechanical cutting equipment, etc.); fitting and rigging; inspection and nondestructive testing (visual, magnetic particle, ultrasonics, radiography, eddy current, etc.); drafting; and underwater photography (still photo and video).

Not all welder-divers posses the variety of skills that may be required to complete an underwater welding project. Diving contractors typically combine personnel resources to satisfy the capabilities required. Hence, the more skills the welder-diver maintains the more valuable he becomes in meeting project qualification requirements. The most desirable underwater welder-divers are those who are qualified to: assist the diving contractor in pre-job planning (e.g., having the ability to photograph/video, draft and report on work requirements prior to the actual underwater welding operation); cut, clean, rig, install, and fit up the sections they will weld; and work with personnel responsible for inspecting the completed welds.

Formal training is recommended for whatever skills you wish to qualify for. Many diving contractors, and the customers they serve, work under quality programs that demand evidence of training and/or qualifications. Therefore, it is recommended that the training you receive be accredited or offer a certificate of completion (e.g., a welding certificate, a diving certificate, an ASNT Level II or CSWIP ultrasonic certificate, riggers certificate, etc.). Maintaining the qualifications you obtain is just as important as receiving them as there has been many a job lost to a welder-diver who has let his certification lapse.

8. What future career opportunities are there for an experienced welder-diver?
There are a number of career opportunities for experienced welder-divers. Many go on to become engineers, instructors, and diving operations supervisors, fill management positions, qualify as AWS Certified Welding Inspectors (CWI), and serve as consultants for underwater welding operations and other related fields.

Ideally, a career as a welder-diver should serve as a stepping stone to other opportunities for those who choose the profession.

Industry has and will continue to demand higher quality standards for underwater welds and more certification of underwater welding systems and personnel. These demands will challenge the underwater welding community to meet more complex technical specifications, safety standards, welding criteria, inspection methods, environmental factors, and other considerations. To meet these challenges, tomorrow's welder-divers will rely on the knowledge and experience of their predecessors who have gone on to become welding engineers, welding engineer divers, supervisors and instructors. These individuals will provide the technical support needed for coming underwater welding operations.

A career as a welder-diver can be an exciting and rewarding profession. It cannot be overstated that safety through training is paramount to any welder-diver candidate.

The majority of work performed by an average welder-diver does not involve the welding operation itself, but rather executing the task that lead up to and follow the actual welding activities. Except under special circumstances, a welder-diver in most cases must possess both certified welder skills and commercial diving skills.

» Read More...

White smoke: White smoke is caused by water and or antifreeze entering the cylinder, and the engine trying to burn it with the fuel. The white smoke is steam. There are special gaskets
head gaskets are the primary gaskets) that keep the antifreeze from entering the cylinder area. The cylinder is where the fuel and air mixture are being compressed and burned. Any amount of antifreeze that enters this area will produce a white steam that will be present at the tailpipe area.

If white smoke is present, check to see if the proper amount of antifreeze is inside the radiator and the overflow bottle. Also check to see if antifreeze has contaminated the engine oil. You can look at the engine oil dipstick, or look at the under side of the engine oil filler cap. If the oil is contaminated with antifreeze, it will have the appearance of a chocolate milkshake. Do not start the engine if the oil is contaminated with antifreeze, as serious internal engine damage can result.

How did antifreeze get in the oil or cylinder in the first place? The engine probably overheated and a head gasket failed due to excessive heat, thus allowing antifreeze to enter the cylinder (Where it is not meant to be).

Blue Smoke: Blue smoke is caused by engine oil entering the cylinder area and being burned along with the fuel air mixture. As with the white smoke, just a small drop of oil leaking into the cylinder can produce blue smoke out the tailpipe. Blue smoke is more likely in older or higher mileage vehicles than newer cars with fewer miles.

How did the engine oil get inside the cylinder in the first place? The car has many seals, gaskets, and O-rings that are designed to keep the engine oil from entering the cylinder, and one of them has failed. If too much oil leaks into the cylinder and fouls the spark plug, it will cause a misfire (engine miss) in that cylinder, and the spark plug will have to be replaced or cleaned of the oil. Using thicker weight engine oil or an oil additive designed to reduce oil leaks might help reduce the amount of oil leaking into the cylinder.

Black Smoke: Black smoke is caused by excess fuel that has entered the cylinder area and cannot be burned completely. Another term for excess fuel is "running rich." Poor fuel mileage is also a common complaint when black smoke comes out of the tailpipe. Black smoke out the tailpipe is the least cause for alarm. Excess fuel will usually effect engine performance, reduce fuel economy, and produce a fuel odor.

How did the fuel get into the cylinder in the first place? Some of the causes of excess fuel are a carburetor that is out of adjustment, a faulty fuel pump, a leaky fuel injector, or a faulty engine computer or computer sensor. If black smoke is present, check the engine oil as in the white smoke example to make sure excess fuel has not contaminated it. Do not start the engine if a heavy, raw fuel smell can be detected in the engine oil. Call your mechanic and advise him of what you have found.

» Read More...

White smoke: White smoke is caused by water and or antifreeze entering the cylinder, and the engine trying to burn it with the fuel. The white smoke is steam. There are special gaskets
head gaskets are the primary gaskets) that keep the antifreeze from entering the cylinder area. The cylinder is where the fuel and air mixture are being compressed and burned. Any amount of antifreeze that enters this area will produce a white steam that will be present at the tailpipe area.

If white smoke is present, check to see if the proper amount of antifreeze is inside the radiator and the overflow bottle. Also check to see if antifreeze has contaminated the engine oil. You can look at the engine oil dipstick, or look at the under side of the engine oil filler cap. If the oil is contaminated with antifreeze, it will have the appearance of a chocolate milkshake. Do not start the engine if the oil is contaminated with antifreeze, as serious internal engine damage can result.

How did antifreeze get in the oil or cylinder in the first place? The engine probably overheated and a head gasket failed due to excessive heat, thus allowing antifreeze to enter the cylinder (Where it is not meant to be).

Blue Smoke: Blue smoke is caused by engine oil entering the cylinder area and being burned along with the fuel air mixture. As with the white smoke, just a small drop of oil leaking into the cylinder can produce blue smoke out the tailpipe. Blue smoke is more likely in older or higher mileage vehicles than newer cars with fewer miles.

How did the engine oil get inside the cylinder in the first place? The car has many seals, gaskets, and O-rings that are designed to keep the engine oil from entering the cylinder, and one of them has failed. If too much oil leaks into the cylinder and fouls the spark plug, it will cause a misfire (engine miss) in that cylinder, and the spark plug will have to be replaced or cleaned of the oil. Using thicker weight engine oil or an oil additive designed to reduce oil leaks might help reduce the amount of oil leaking into the cylinder.

Black Smoke: Black smoke is caused by excess fuel that has entered the cylinder area and cannot be burned completely. Another term for excess fuel is "running rich." Poor fuel mileage is also a common complaint when black smoke comes out of the tailpipe. Black smoke out the tailpipe is the least cause for alarm. Excess fuel will usually effect engine performance, reduce fuel economy, and produce a fuel odor.

How did the fuel get into the cylinder in the first place? Some of the causes of excess fuel are a carburetor that is out of adjustment, a faulty fuel pump, a leaky fuel injector, or a faulty engine computer or computer sensor. If black smoke is present, check the engine oil as in the white smoke example to make sure excess fuel has not contaminated it. Do not start the engine if a heavy, raw fuel smell can be detected in the engine oil. Call your mechanic and advise him of what you have found.

» Read More...

A timing belt, or cam belt (informal usage) is a part of an internal combustion engine that controls the timing of the engine's valves. Some engines, like the flat-4 Volkswagen air cooled engine, and the straight-6 Toyota F engine use timing gears. Timing belts replace the older style timing chains that were in common usage until the 1970's and 1980's (although in the last decade there has been some reemergence of chain use). The term "timing belt" is sometimes used for the more general case of any flat belt with integral teeth, although such usage is a misnomer since there is no timing or synchronization involved.


Engine applications

In the internal combustion engine application, the timing belt connects the crankshaft to the camshaft(s), which in turn controls the opening and closing of the engine's valves. A four-stroke engine requires that the valves open and close once every other revolution of the crankshaft. The timing belt does this. It has teeth to turn the camshaft(s) synchronised with the crankshaft, and is specifically designed for a particular engine. In some engine designs, the timing belt may also be used to drive other engine components such as the water pump and oil pump.

Gear or chain systems can also be used to connect the crankshaft to the camshaft at the correct timing. However gears and shafts constrain the relative location of the crankshaft and camshafts. Even where the crankshaft and camshaft(s) are very close together, as in pushrod engines, most engine designers use a short chain drive rather than a direct gear drive. This is because gear drives suffer from frequent torque reversal as the cam profiles "kick back" against the drive from the crank, leading to excessive noise and wear. Fibre gears, with more resilience, are preferred to steel gears where direct drive has to be used. A belt or chain allows much more flexibility in the relative locations of the crankshaft and camshafts. Timing belts or chains are also able to even out wear, since they can be made such that the number of teeth on the belt is coprime to the number of teeth on the crankshaft and camshaft sprockets, thus ensuring that each tooth on sprocket does not end up on the same tooth on the belt repeatedly.

While chains and gears may be more durable, rubber composite belts are quieter in their operation (in most modern engines the noise difference is negligible), are less expensive and are mechanically more efficient, by dint of being considerably lighter, when compared with a gear or chain system. Also, timing belts do not require lubrication, which is essential with a timing chain or gears. A timing belt is a specific application of a synchronous belt used to transmit rotational power synchronously.

Timing belts are typically covered by metal timing belt covers which require removal to carry out visual inspection. Engine manufacturers recommend replacement at specific intervals.[1] The manufacturer may also recommend the replacement of other parts, such as the water pump, when the timing belt is replaced because the additional cost to replace the water pump is negligible compared to the cost of accessing the timing belt. In an interference engine, or one whose valves extend into the path of the piston, failure of the timing belt (or timing chain) invariably results in costly and, in some cases, irreparable engine damage, as some valves will be held open when they should not be and thus will be struck by the pistons.

Indicators that the timing chain may need to be replaced include a rattling noise from the front of the engine.[2]
Timing

When an automotive timing belt is replaced, care must be taken to ensure that the valve and piston movements are correctly synchronized. Failure to synchronize correctly in an can lead to problems with valve timing, and this in turn, in extremis, can cause collision between valves and pistons in Interference Engines. This is not a problem unique to timing belts since the same issue exists with all other cam/crank timing methods such as gears or chains.
Failure Modes

The usual failure modes of timing belts are either stripped teeth (which leaves a smooth section of belt where the drive cog will slip) or delamination and unraveling of the fiber cores. Outright snapping of the belt, because of the nature of the high tensile fibers, is very uncommon.[citation needed] Correct belt tension is critical - too loose and the belt will whip, too tight and it will whine and put excess strain on the bearings of the cogs. In either case belt life will be drastically shortened.


Construction & Design

A timing belt is typically rubber with high-tensile fibres (e.g. fiberglass or Twaron / Kevlar) running the length of the belt as tension members.[3]

Rubber degrades with higher temperatures, and with contact with motor oil. Thus the life expectancy of a timing belt is lowered in hot or leaky engines. Newer or more expensive belts are made of temperature resistant materials such as "highly-saturated nitrile" (HSN).[citation needed] The life of the reinforcing cords is also greatly affected by water and antifreeze. This means that special precautions must be taken for off road applications to allow water to drain away or be sealed from contact with the belt.

Older belts have trapezoid shaped teeth leading to high rates of tooth wear. Newer manufacturing techniques allow for curved teeth that are quieter and last longer.


Aftermarket timing belts may be used to alter engine performance. OEM timing belts "will stretch at high rpm, retarding the cam and therefore the ignition."[4] Stronger, aftermarket belts, will not stretch and the timing is preserved.[5] In terms of engine design, "shortening the width of the timing belt reduce[s] weight and friction".[6]


Usage History

The first known timing belt was used in 1945.[7] The German Glas 1004 was the first mass produced vehicle to use a timing belt in 1962. The first American vehicle to use a timing belt was the 1966 Pontiac Tempest. In 1966, Vauxhall started production of the Slant Four overhead cam four-cylinder design which used a timing belt, a configuration that is now used in the vast majority of cars built today.

» Read More...