Not that it is hard for these companies, if they decide.

But their business model focusses on providing (or at least trying to provide) better driving experience and features through novel (novel, not necessarily proven) techniques without considering the reliability and cost. If something (like DSG) can transform the customer experience, they won't hold it until they develop it's reliability.

While conceiving the products, advertising, pricing, selling as well as servicing too, they target high net worth individuals as their customers. They expect customers for whom 25-50k for routine service is peanuts and 5 - 10 lakhs for a major repair looks ok. For whom, keeping one car standing at the service station for a month isn't a problem. For many of whom, it is not even their own money to maintain the car. In return, they offer to provide socio-economic differentiation for their customers.

If we opt for this better driving experience and socio-economic differentiation without realising the costs during the life cycle, then we are in for trouble.

Most in the neo rich class are (financially and mentally) prepared to bear the cost of acquisition but not the cost of maintaining.

In petrol vehicles timing chain breakage / slippage will not impact the engine, these engines are called non interference engines. In these engines, the pistons and valves don't occupy the same space, so if the timing chain jumps or the timing belt snaps, no valve or cylinder damage occurs. Most petrol vehicles are non interference engines.

If it is a diesel vehicle, the valves in the head directly sits on the pistons, so breakage of timing belt will immediately bend the valves in the engine head, thereby damaging main engine cylinder head, pistons, piston rings and camshaft. diesel engines are mostly interference engines.


Also your car is close to 1 lakh kms, didn't you get your timing chain kit replaced? I'm not sure about your car, but most of the cars have 1 lakh km replacement life. In our Toyotas, timing belt is changed at 1.5 lakh kms. But I still suspect some foul play by your dealer, get engine compression test done if the engine cranks, don't keep your vehicle in service center for too long, they might steal your parts and even charge you exorbitantly for parking if you wish you take it elsewhere for repairs. Get an inspection and quotation from FNG if you wish to get it repaired without getting fleeced by predators like Skoda service centers.

Sorry, but the notion that all petrol engines are non interference and diesels are interference engines is totally wrong. Nothing to do with the kind of fuel. Feel free to google list of interference engines.

E.g.
http://yourcarangel.com/2014/07/inte...complete-list/

Jeroen

TSI - Gasoline direct injection with Turbo, everything is staring right at the top of the piston.

They use a timing chain in this case, they are good for a few 100,000 kms and does not need replacement like a timing belt, provided the inspection is done as per schedule. Inspecting the chain and tensioner after having to rip a large amount of things from the engine bay is probably not always done.

True, it is not because of the fuel.

But why do valves in a petrol engine need to interfere with the swept volume when these don't need compression ratio of the order of a diesel engine?

They allow the engine to “breath” more effectively. The valves open earlier, close later and open wider.
Which potentially means more air, thus fuel, thus power and better fuel efficiency.

It also allows for a slightly more compact design and thus lighter engine.

In cars, petrol and diesel the majority of engines these days are interference engines.

Jeroen

Correct, I mentioned this in my earlier post. On some engines it can be relatively easy to measure chain wear. You can measure the difference in timing alignment between crankshaft and camshaft. Just as I showed in my timing chain replacement story.

As the chain wears it effectively becomes longer and that means the timing between camshaft and crankshaft changes. Ideally you need to have taken readings every 25-35.000 km. Not sure if anybody does it. But it used to be part of normal services with earlier Mercedes models for instance.

Doesn’t work with belts. They hardly stretch, but just snap!

Also, the use of duplex chains over simplex chains has increased the lifespan of distribution chains.

Jeroen

I hope the damage is minimal.
The timing belt on my Punto had given away when I was driving at not-so-high speed. My FNG showed me the damage it had caused to the engine blocks. He had quoted 90k for its rebuild but I got only the upper engine rebuilt for around 30k. He was transparent that the car will run but is only a stop-gap solution. There was a noticeable loss in performance and I just sold the car off by also being transparent to the buyer.

Damage is not necessarily limited to the head only. If anything at least one piston will be damaged. The crankshaft bearings and respective drive rod bearing needs inspecting and replacing/ overhaul if damaged.

Which still means taking just about the whole engine apart. On most cars this is an engine out operation, in order to get access to the crankshaft and pistons.

Jeroen

Thanks for sharing, that is the reason why I mentioned most petrol engines, instead of all engines, atleast in India, majority of gasoline vehicles (which my mechanic said) with 8V, 16V are non interference engines, I did not have a correct idea about 1.8 TSI, so I did not mention it directly.

OT: In the link you posted, they mentioned that all Nissan engines are interference engines, during last service of our Nissan Sunny Diesel, the SA asked us to change timing belt as it is already 8 years old, but with only 34 K on the odo, do you think I should change the belt along with the timing kit or can I run it till 1 lakh kms? The SA told me that the belt would have become hard and might have developed cracks internally due to age, is that analogy true? I searched on google but couldn't get a satisfying answer on the same.


Thanks for sharing, yes timing chain doesn't need to be changed like timing belts, which wear out or can break sometimes. But the authorised service center mechanics should have atleast checked it when the OP gave his vehicle during the 98 k kms service. As you said, they might have to open lot of other components to inspect the chain and tensioner, so they might have avoided this step.


In our Toyotas, we get a timing belt light at exactly 1,50,000 kms and we promptly changed the belts. The belt lasted 7 years and 150 k kms on Innova and 4 years and 150 k kms on Qualis and another belt was replaced exactly after 6 years and 300 k kms (total) on Qualis, now it is running on it's 2nd timing belt and is close to 16 years and 4,23,000 kms, probably we need to change it at 4,50,000 kms. I'm not sure if skoda provides a timing chain light on the instrument cluster when it is due for replacement.

In all honesty, I have not heard of replacing belts ahead of their scheduled interval which is always based on km, not years. The SA story might have some truth in it, but to what extend I don’t know. At some point in time, these sort of things can become a bit of a burden on your mind, so you might as well go ahead and change it.

On my Mercedes there is no official guidance for replacement of the timing chain at all. It is simply not mentioned in the maintenance schedule. So the internet is awash with stories and arguments ranging from every 50K km over 100000km to never change it all. My approach was better safe than sorry. The parts tend to be not that expensive. In the western world it is the man-hours that makes it expensive. As I do all of my own maintenance, that is not a consideration or a concern for me.


If it is not mentioned in the official maintenance schedule, it is not going to be inspected, no matter what the internet thinks of it. Would be interesting if people could check what their owners manual says about chain/belt inspections and changes! I suspect very little no nothing on inspections! For the reasons discussed earlier.

Thanks for sharing. I was not aware of these timing belt change indications. They must be set for exactly 1,50.000 kms!

Just one more thing on the non interference engine. If the chain or belt snaps on such engine their will be less damage. Obviously, the valves will not smash into the pistons. Even so, there might be other damage. Especially with a chain. If a chain snaps at several thousands of RPM, it is going to be whiplashing thought the front of the engine. It can seriously damage the tensioners, the sprocket wheels. Also, all kinds of metal bits will be all over the engine. So you need to, at least open up the sump clean everything out, make sure no bits are stuck in cracks, the oil pump etc. On many engines with a chain, getting access to the main tensioner will also mean removing the front cover, which again is a big job. Removing sump and or front cover often means an engine out job to start with.

With the belt there is less change of damage when it snaps and whiplashed around. Belts tend to be on the outside of the engine, usually under some cover. But at least you can get access to all components fairly easy.

Jeroen

The timing chain on the engine looks to be different in construction, compared to the simplex / duplex / triplex chains we use in the industrial transmission.

Here is how the timing chain on the M16A petrol engine of my SX4 looks. It looks to be a quadruplex (4 fold) chain. I am happy to see a strong chain, which cannot easily elongate. MSIL has not recommended any replacement interval for this chain.

Attached Thumbnails

 

I assume you are referring to the photographs of my Mercedes Timing chain? Yes, that is a very simple simplex chain. Later version of this particular engine, M102, when it made it into the Mercedes W124 had already a duplex chain.

That looks like a very sturdy chain indeed. Even the chain om Jaguar V8 is just a simple duplex.
Looks like they are doing some work on this one though? Is it your car? Interesting to see how you can get access with the engine in the car.

You can clearly see the tensioners, although the chain is just hanging at this point, to the left of it

Jeroen

Isn't it a bit surprising that they did not put an electronic sensor to warn you of loose chain?.

I know if lot of industrial applications where tension needs to be maintained , textile and paper printing for instance and depending on application, specific sensors are used. For instance in a paper printing machine a laser sensor (used in a closed loop control) keeps the paper taut. For a timing chain an inductive proximity would do the job just fine. Even in a open loop it can produce a warning light.

Just wanted to highlight that while engines get so complex with sensors for starting your wipers in case of rain , they overlooked a critical part.

The timing chain tensioners in the EA888 1.8/2.0TSI engines circa 2010 are ticking untimed bombs. Question of when not if. One of the consequences : "When the timing is off because of a failing timing chain, the engine pistons smash into the valves, and the entire engine can be damaged beyond repair"

Here is a thread that has good pics and comparisons of the old and the new ones.

https://www.audizine.com/forum/showt...e-Thread/page2

I found this while searching about frequency of oil top-ups in the 1.8 TSI engines, and out of panic got the part replaced at 60K itself. I asked my FNG to do this. He didn't see anything wrong so wondered why I wanted to do it. He called his contact at a Skoda service centre, and they told him "karna hai to karo, jaroori nahi hai". So either they were clueless or didn't care or didn't want to admit.


The older part no is 06H 109 467 (N/AB)
The newer safer one is 06K 109 467.

SAVW should be putting out an advisory to all TSI engines that don't have the latest one.