TIMING CHAINS vs. BELTS - Differences, Evolution, History and more

What's wrong with engine heads today? We'll take a look at

timing

belts

and

chains

, compare one to the other, and then delve into the details of these two critical automotive components, while also presenting objective data on both, so no. The typical generalizations like

belts

are quieter but

chains

last longer and that's it, no, there is much

more

and we will try to hide it. We will also take a look at the

history

of belts and chains and how one dominated over the other in different periods of automotive

history

and how this influenced the

evolution

of these components and how it affects you as a car owner, but First the basics: what does a spoke

timing

chain do really well?

The key word here is timing the strap task. or chain is to maintain the timing of the engine and by timing we mean the relationship between the pistons and the valves or the crankshaft and the camshaft this relationship must be kept constant at all times now the crankshaft is physically connected to the camshaft a through a belt or chain and what the belt or chain does is drive pulleys or sprockets. A belt drives pulleys and these chain sprockets. Now both the pulleys and the sprockets do the same thing, together with the belt or chain, they maintain the synchronization of the engine and a camshaft pulley or sprocket will always have twice as many teeth, so double the teeth of a crankshaft pulley or sprocket to ensure that for every two r

evolution

s of the crankshaft, the camshaft makes one revolution, so what's the problem?

Both timing structures and distribution chains do the same thing. They just look different and use different materials, one is metal, the other is rubber, and this topic deserves a video? Well, yes, it does because, in addition to having different materials, using a timing belt or timing chain has implications for the design of the entire engine, as well as the frequency of its maintenance and its durability, so one thing It's obvious: metal is stronger than rubber, which means that a metal chain is stronger than a belt with rubber teeth and if you had to hang a lot of weight from a chain and a belt the belt would probably break first , but who cares, this is a stupid example because hanging weights is not what motors do, what motors do is spin, they spin a lot and start spinning from the moment you turn the key and during a typical day of use, a motor will rotate

more

than a million times, which means that during a month of use, a motor will rotate more than 30 million times, that is a lot of rotations, so this means that the problem here is in tensile strength of the chain or belt the problem is how well the chains and belts resist wear again chains seem to be the winner here because metal resists wear better than rubber, but there is a problem: metal resists wear wear better than rubber only when lubricated and this brings us to our first big difference between chains and belts: belts dry out, but chains need oil to prevent them from wearing out quickly and this means that a chain should be sealed away from the middle environment to prevent oil leaks and the easiest way to tell if your engine actually has a belt or chain, look at the engine if it has plastic covers it probably has a belt, if it has metal covers on the front , it likely has a chain and because of this, a chain motor generally requires a little more space in the engine compartment compared to the same belt motor because they are more durable than belts.

Timing chains have much longer service intervals. Some timing chains don't even have a service interval. They last the entire useful life of the engine. engine which is always a good thing, on the other hand you won't find a belt that can last the life of the engine, even if you don't use the engine at all you will still have to replace the belt every four to ten years depending on the engine and This is because rubber naturally deteriorates over time, even if it is stopped it will degrade. Timing belts are also sensitive to oil and coolant spills, so a leaking engine will wear its belt much faster than a leaky engine. no leaks, rubber belts don't like high temperatures, rising temperatures increase rubber wear and as we all know things can get quite hot in the engine bay, now a typical modern engine has a belt service interval of around 60 to 80,000 miles now I say modern engine because sometimes in the mid to late 90's the timing materials received a significant upgrade in general the timing belts feature a rubber with reinforcing fibers, these fibers are usually Kevlar or fiberglass and increase the tensile strength of the belt. the rubber itself is usually welded urethane or molded urethane or neoprene or something like that but in the mid to late 90's rubber strap started to include hsn which stands for highly saturated nitrile and this is a material that is quite strong at high temperatures and increased significantly.

The service interval for timing belts, older engines with timing generally had a service interval of around 15 to 35,000 miles for the belt when it comes to timing chains, when they have a service interval it is around 80 to 120,000 miles and although metal is stronger than rubber, rubber is much softer and lighter, which means that belts generally run quieter than chains and also have less friction and less inertia, which This means they are easier to spin, which reduces parasitic horsepower losses. Rubber is also excellent at absorbing vibrations and harmonics. of an engine, resulting in an engine that can feel smoother and, although timing belts are generally very similar in design and do not differ much from each other, timing chains come in two different types, the silent chain and The roller chain, the silent chain as the name suggests is silent and no matter how much you question it, the silent chain actually reduces the amount of noise generated by the chain and sprocket assembly.

Silent timing chains are quite common, you can find them on many engines and manufacturers love them because they are simple and cheap to make. A silent chain consists of multiple links joined by pins. The profile of the links fits the profile of the teeth on the chains. sprockets and rests the chain rotates makes the sprocket rotate yes, pretty simple now on the other hand the rover chain uses rollers on these pins and as the chain rotates the sprocket the rollers rotate on the teeth of the sprocket, this of course reduces friction, which is good because it reduces parasitic horsepower losses but also reduces localized wear on the chain.

Now roller chains are more expensive compared to silent chains. When it comes to Rover chains, there is another problem and they are actually a little louder compared to silent chains. Roller chains also come in two different types, with single and double rollers, and as you already know. I suppose the double roller type is stronger, more durable, extremely difficult to break, but it does offer a disadvantage because it creates more friction because it has more surface area, which means more loss of prosthetic horsepower. Another difference between silent chains and roller chains is that rubber chains are a little more sensitive to contaminants in engine oil, so the chains are lubricated with engine oil.

Now this is both a strength and a weakness. It is a strength because lubrication reduces wear. It's a weakness because lubrication is only as good as the oil inside. engine and the reason for premature chain stretching and failure is almost always one of the following three: the oil was not changed on time the oil was of the wrong viscosity or the oil was of very low quality any of these three can significantly shorten the Chain life spans expand and create a risk of chain failure. Now roller chains are particularly sensitive to oil that has been in the engine for too long.

This type of oil will have more contaminants and these contaminants can become trapped between the rollers and chain pins. which accelerates chain wear, so as long as you use the right oil and change it on time, chains are the best option after all, a chain is more durable, less likely to break than a belt and change the supply or maintenance costs, and this is what the average buyer wants and needs for the chains to win, well, actually no, they don't, and to see why they don't, we have to start the historical segment of our video because it will demonstrate how chains and straps evolved over time and how things are.

It's not always as it seems in the 50s and 60s, all car engines were chain driven. Belts didn't exist and back then chains lasted the life of the car. There are two reasons for this reason, number one is that the cars didn't really work. Covering the miles that a car with 200,000 miles on the clock does today was pretty rare and reason number two is that the engines weren't as twitchy as they are today, but more on that later, the first engine that used a rubber band. The tube he built was a special racing engine built by Bill Devon in the early 1950s.

He used to use Norton Manx motorcycle cylinders which he installed in a paneled crankcase and the engine was an overhead cam design and cylinders horizontally opposites, which meant using a chain for this. The engine was simply impossible with the technology available at the time, so Devin used a rubber timing belt and this car with this engine won the Sports Car Club of America championship in 1956. The first mass-produced car to feature a rubber belt driven motor. It was the West German Glass 1004, it hit the market in 1962 and had an engine that generated 42 horsepower at 5000 rpm. The interesting new engine was designed by Leonard Ischinger, who was a former BMW employee.

Interestingly, BMW bought glass in 1966, not because they wanted the cars or the brand, but because they wanted access to the timing belt patents. '66 was actually a great year for timing belts because in this year Fiat introduced the first twin cam engine driven by a romper belt and in the same year. America also got its first belt-driven engine in the form of an overhead camshaft from Pontiac's straight 6. So what do all these pioneers in timing construction have in common? You guessed it, they are all overhead cam engines compared to a pushrod engine, the distance between the crankshaft and camshaft are much greater in an overhead cam engine so you would need a much larger chain. long to connect the cam to the crank and with the technology available in the past, this meant that the use of chains and overhead cam motors had rather poor results. many chains on these engines spun and rattled, got too loose and wore out too quickly and did all sorts of undesirable things, so many manufacturers opted for timing belts for their overhead camshaft engines, now this doesn't mean In the 60s and 70s there were no good chain driven overhead cam engines, but the number of belt driven engines on the market began to increase with the number of overhead cam engines on the market and this number began and by the mid-1980s, timing belt-driven engines outnumbered chain-driven engines in many parts of the world.

The dominance of timing continued through much of the '90s and even the early 2000s in some parts of the world, but belt-driven motors also got a bad rap now. most spell driven engines were totally fine and never had problems with their belts, but some engines like to break a belt before it's even time to replace it and when this happened on an interference engine, the The results were almost always catastrophic for both the motor and your wallet, so it's no wonder belts get a bad rap because when you compare them to chain driven motors that have never broken a chain, they seem like an inferior option and I really can't Blame the average consumer for seeing the new strap. boosted engines as an additional maintenance cost and additional risk, but in the mid-2000s manufacturers began to return to chains mainly because they couldTechnology had improved new coatings new heat treatments better chain engineering technology all meant manufacturers could make chains lighter than ever before. reduce friction, they could reduce parasitic horsepower losses, they could improve wear resistance, so many manufacturers simply went back to using chains for their overhead cam engines and it was really a win-win: buyers would get the promise of greater durability and lower maintenance costs and manufacturers would improve In sales, the chain came back with all my chains, but the second time, unfortunately, there was a problem.

Old and new chains seem to be two different things to demonstrate. Let's look at a concrete example. Two different engines. An old chain driven overhead camshaft engine. and a new chain-driven overhead cam engine, they are quite different, they don't even use the same type of fuel, but bear with me, the comparison will make sense. Our old engine is the Nissan L24. It is definitely old, made from '69 to '84. It can be found in Nissan 240z among other cars and is a 2.4 liter in bugs. Our modern engine is the BMW and 47. It can be found in several different BMW and Mini cars.

It was manufactured from 2007 to 2014 and has. two different displacements and it's an inline four turbodiesel so they are quite different but they are both overhead cam chain driven engines and as you can see the bmw and the 47 make more power with less displacement and fewer cylinders, In fact, the BMW M47 was the first mass-produced diesel engine to achieve a specific power of over 100 horsepower per liter of displacement, an astonishing achievement for a diesel and definitely an amazing engine and it is even quieter, smoother, it is everything more than the L24 and it does everything. with less fuel than the l24 which is not surprising because it is much more advanced and much more modern but unfortunately the n47 is famous for something that the l24 is not the n47 is famous for breaking chains, on the other hand, find an l24 with a snap chain is almost impossiblethe chain may rattle and wear but it will almost never break so why is the n47 which has access to newer and better technology worse in chain durability compared to the old l24 and the answer to this is that the n47 has To tick many more boxes compared to the L24, it has to please a much more demanding car buyer.

Over time, car buyers' expectations have increased exponentially. The modern car buyer wants his engine to do virtually everything he wants, the power he wants, the torque he wants. They want the engine to be quiet, they want the engine to be smooth but they also want good miles per gallon and low emissions, as you can see a lot of these things are in direct opposition to each other and making one engine that does it all is impossible but still So car manufacturers have to sell cars, so they have to try to please the modern car buyer. On top of all this, the modern car buyer also wants low maintenance cost, so BMW gave the m47 a timing chain to reduce maintenance costs, but the n47 also has to make power, so BMW gave it a single roller timing chain to reduce friction compared to the double roller timing chain on the L24, but even this was not enough because the modern car buyer does not want to change the oil too often, so BMW gave it the n47. an oil change interval of 15,000 miles compared to the L24's oil change interval of 5,000 miles, so the N47 has to do more of everything with less fuel and old oil.

It's like an athlete trying to win the Olympics on a diet of junk food something has to break but let's not make BMW the only scapegoat here here's some honda k series b series b series was the oldest main engine had a belt timing the k series is the most modern honda main engine has a timing chain the belts on the The b series almost never broke, even in the hands of lazy owners who refused to change them on time, on the other hand, the series k had timing chain tangency problems, even with very low mileage, the consequences were not as horrible as on the n47.

The K series chain wouldn't break completely, but it would stretch a lot, causing a lot of annoying problems, and if left unattended, it would stretch so much that it would jump a tooth on the sprocket, causing the engine to It would work completely. horribly, so yeah, what am I really trying to say here? Well, first of all, I am trying to say that you should not be fooled. These are just two examples and there are many modern engines with timing chains that have no problems, but the timing chains. They no longer guarantee the kind of durability and low maintenance costs that they used to have in the past due to the stresses and demands placed on modern engines, belts and chains are even, it is now a matter of case by case and when choosing a engine should Really research that specific engine so you can predict the maintenance cost and see if it fits your needs, preferences and your budget, because today a chain could mean more maintenance costs than a timing belt.

Basically, things have changed, so what is the future of sync builds? and chains, well the future is that they could disappear completely if free valve becomes commonplace, but that's a topic for another video and this video is practically over. I hope you enjoyed it and found it useful, informative and maybe even a little entertaining if you like. have any other questions, ideas, comments, suggestions, any comments section just below, as always, thanks so much for watching and we'll see you soon with more fun and useful stuff on the d4a channel.