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...

Hole punches are one of the most versatile office products you can buy. A hole punch offers an inexpensive way to bind your documents using three-ring binders and it can also prepare them for storage in file folders. Swingline produces some great hole punches, including a wide range of heavy-duty models. One of these is the Swingline LightTouch heavy-duty hole punch. If your office punches a lot of paper and you need a hole punch that can produce several different hole patterns, this is one machine you should definitely learn about. So to do just that, please continue reading.

The Swingline LightTouch hole punch is a machine that is easy to use and has a lot of different punching settings. It is capable of producing several different punching patterns from two-hole to seven-hole. This gadget can punch up to 40 sheets of paper at once, so it's perfect for offices that need a machine with a high punching capacity.

The punching heads on the LightTouch are top-of-the-line and produce beautifully clean 9/32" holes in your document. The whole unit is well-constructed and it has a top-loading system that makes it easy to load your document. You'll also be able to save space in your crowded office thanks to the punch's locking lever. The chip tray has a transparent cover so you can see when it's getting full and know when to empty it. This hole punch also has a unique, contemporary look so it will blend in with whatever decorating scheme you have in your workplace.

Perhaps the best thing about the LightTouch - aside from its adjustable pin configuration and its 40-sheet punching capacity - is its usability. The LightTouch is incredibly easy to use, even if you have medical issues that make it difficult to use certain office machines. The LightTouch has a pull-down lever that's easy on your muscles and joints. (This hole punch even won the Ease-of-Use award from The Arthritis Foundation.) In fact, the LightTouch is so easy to use, you'll use 50% less effort than you would if you were using a different punch. The LightTouch is also a jam-proof machine, which only adds to its user-friendliness. It also comes with a limited lifetime warranty.

The Swingline LightTouch has one final perk: it's pretty affordable and can be yours for less than $100.00. This is a great price especially when you consider what this gadget has to offer, such as its punching capacity, unique space-saving design, and the semi-adjustable punching patterns. It's also great that the LightTouch can be used by anybody, even those with joint problems. Not a lot of hole punches are as user-friendly as the LightTouch, it's safe to say.

If your office needs a heavy-duty hole punch, the Swingline LightTouch should definitely be up for consideration. It's affordable, well-made, and everyone will find it easy to use. Plus, it offers several different punching patterns and it can help you achieve more in less time, thanks to its punching capacity. Get a Swingline LightTouch heavy-duty hole punch for your office and enjoy more punching power!

If you are thinking about purchasing the Swingline LightTouch heavy-duty hole punch, you should really check out MyBinding.com. They offer a great price on this machine and carry the full line of Swingline Hole Punches. Plus, they offer free shipping on all orders over $75. Check them out today!

» Read More...

There are different forms of transport that people can use. Among those is the electric hybrid car
. The various models of electric hybrid car afford people the choice of having a stylish-looking vehicle which at the same time conserves gas.

Furthermore, the environment is kept more pollution free by these electric hybrid cars. The types of hybrid cars which you see included in the range of electric hybrid cars will be the popular SUVs, sports cars and pickup trucks. You will have the chance to see those latest electric hybrid cars which are due to come on to the market. As there are many types of electric hybrid cars you should look to see whether there are any performance reviews available.

This knowledge will help guide you when you are trying to make up your mind about which electric hybrid car to choose. You will need to realize that some of the electric hybrid cars will not be that easy to repair or have their parts replaced. This is one factor that you should keep in mind while you are shopping for the electric hybrid car that suits you.

There will be times when you will not be able to find the exact model of electric hybrid car that you want. In order to diminish this frustration, make a list of several different electric hybrid car types, (include some of the best known electric hybrid car types).

You may also want to make a list of the other most important qualities that you are looking for from an electric hybrid car. Don’t forget that you should visit the car showrooms to see the electric hybrid car of your choice, as I’m sure you may appreciate seeing what sort of cars are available before you buy one.

As there will be times when you will not be able to get hold of the details of all of the electric hybrid cars on the market, you should find some other way of getting this information. Of the different ways that you can look up the many models of electric hybrid car, the Internet can provide you with pictures, specifications, descriptions and reviews of the different makes of electric hybrid car. For example, you can access the information for the current stable of hybrid Honda cars or the previous models too. Among the many details that you can find are: the number of seats and the safety and engine specifications of these hybrid cars.

There are, as we all know, many different types of hybrid car that can be bought. These will, for the most part, be well-known car brands. You will find that Honda which is a world-famous manufacturer of cars with modern technology also has their version of a hybrid car. The electric hybrid car is one of their hybrid cars that is very popular with the public.

» Read More...

I think many of us with vehicles seriously overestimate or underestimate what we could tow with it. You might look at a boat, utility trailer, or travel trailer and ask yourself “I wonder if my car could handle that?”

Now where would you go for that kind of information? Most people would go straight to the owner’s manual of their car. The problem is, the information in that manual will be so watered down and generic that you can’t really trust it.

It’s going to say something like this: “towing capacities are calculated under the assumption of a standard equipped vehicle, normal driver, and trailers. Any other equipment or passengers will reduce the amount of weight your vehicle can handle.”

Huh? So how on earth can you evaluate your real towing capacity? The first thing you have to understand the vehicle manufacturer is using a completely stripped down version of the car or truck to beef up the towing rating. Makes sense right?

They’re trying to sell cars, and if you’re a family with a tent trailer, seeing a super high towing rating on that little station wagon could be the factor that gets you to buy. That’s why you need to bring a skeptical eye to that owner’s manual.

The last thing you want is to load up your trailer with a few quads or motorcycles, head up to the mountains, and then have your transmission go out because you trusted the manufacturer’s published towing capacity. That could be a very expensive getaway.

Here are some terms you want to be familiar with in evaluating your actual towing capacity:

Unloaded Vehicle Weight (UVW)
You know all those times you’re headed down the interstate near the border of the state you’re entering or leaving? One of the best ways to find out your unloaded vehicle weight is to stop at one of them, pay the $5 or $10 fee, and have them weigh your car or truck.

If you do stop at one of those weigh stations, try to have your gas tank as full as possible to make the measurement more accurate.

Gross Vehicle Weight Rating (GVWR)
This is the maximum weight your tow vehicle can be without wrecking your car, truck, or suv. There are a few places you might find this number – it might be under the hood in the engine compartment, or on a sticker in a door frame, or maybe even in the owner’s manual. It’s important to know this number because the foundation for safe towing is not attempting to pull something that is just too heavy for your car.

The bottom line when towing is not to overdo it. When you buy a vehicle, if you know it’s going to be used for towing, be realistic about the capacity of the car or truck you’re buying.

The lightweight family sedan you’re buying is probably not intended to pull a 20 foot boat, or a large travel trailer. If you know you’re going to be doing lots of traveling, camping, RVing, and other recreation, be honest about what type of tow vehicle you’re going to need.

I would recommend buying a solid 8 cylinder engine with a transmission calibrated for heavy duty jobs. I would rather overkill on the vehicle than risk doing thousands of dollars in damage to my car or my trailer. Not to mention the people I’m sharing the road with.

Jeremy teaches people about installing a trailer hitch and also advises them on the right way to set up trailer hitch covers.

» Read More...