Engine "loosening up" - real or bullpoo?

[Item]

So as I approach the first 10000km in my new VRS, I have felt over the last week or two that the car seems slightly quicker/more eager on hard acceleration. I also seem to be getting slightly more out of a tank - around 60-70km.

 

Is this just placebo effect/faulty butt-dyno and the application of some unnoticed external factor causing this or is there truth in the whole "engine loosening up" theory that seems to persist?

[Wakey]

It's true.

 

If you think about all the moving parts in the engine and gearbox that make contact when moving - all this contact results in resistance. 

 

As a car mileage increases the parts bed in due to slight wear and the resistance decreases allowing the engine to work with less resistance. Things move more freely.

 

Imagine a block of ice cream in a bowl and then you using a spoon to stir it - as it melts it becomes easier and faster

 

Also, the piston rings bed in and make a better seal in the cylinder liner and compression and therefore torque (and power) improves.

[Gerrycan]

It certainly was true in the 'bad old days', when there were carburettors, contact breakers and things, but is much less of an issue nowadays with much tighter manufacturing tolerances.

I have never noticed any marked improvement in consumption on any new car I have purchased that I could not account for by improved driving technique as I learnt the characteristics of the engine/transmission.

However others will swear differently and I respect their own experience.

I actually hope it is true because I'm always striving for improved consumption.

Some days a car can seem to run better than others for no apparent reason, but it is so subjective, it could be just my mood?

 

A relative of mine in the UK works for a major car manufacturer and they make the jigs and patterns (whatever they are called?) for the engine assembly. During last summers very hot weather they were struggling to make them to the required very tight tolerances because the factory was not air conditioned and the metal expansion limited production to cooler periods of the day/night. Gives some idea of the tolerances they work to these days.

Edited 30 September, 2016 by Gerrycan

[Gabbo]

I think these days the mechanical part of an engine "loosening" is much less noticable then before.

Parts are machined with very tight tolerences & measured components are often matched to give optimum fitting.

I'd imagine that over 1000km or so the components which bed in would be nicely fitting.

 

However, there was another thread on here where several users (not just one or two) seemed to suggest that after hitting a certain mileage (I cant remember the exact number) the average economy or miles per tank suddenly jumped 10%.

This would suggest some kind of software based engine protection.

 

However, in my car following the fuelly average I see no real change over the last 60k km.

[Jono]

My opinion is that it's mostly a myth.

 

It's a very big industry and so there would be some credible evidence by now if it were true.

 

I'd welcome being proved wrong* I like learning things.

 

 

 

*Anecdotes are not evidence. The plural of anecdote is not evidence.

[Sheldon.Cooper]

At 16,000 miles I suddenly got 8mpg better. Couldn't feel any difference in acceleration, carrel no different, journey's were the same, pretty much overnight at that mileage a constant 8mpg. Maybe a software switch but not a mechanical loosening up....that would be more gradual.

[flybynite]

Well I used to think the overnight consumption drop was an urban myth until it happened to mine. Not sure it happened at any particular mileage but a marked change (for the better) in average fuel consumption calculated brim to brim. Same driving, same routes same temperatures and it has not gone back to previous levels to-date.

 

Seems like it was just a touch overfuelled to begin with. Not an unreasonable thing to do with a new engine IF it were the case. If they can program a defeat device into the system, not particularly out-there as a possibility either.

 

I have changed oil at around 1000 miles on new or rebuilt engines since the days when they needed it. They all made metal to some extent when new. With a hundred tubes of plastigauge I could not get the tolerances they get in production today, but I still change the oil.

 

It would have been nice to see if the Octy did make metal when I changed the oil at 1000, however metal does not stick to the cheap **** plastc sump plugs so I am blissfully ignorant.

 

I have changed oil in other modern engines (with proper magnetic sump plugs) at 1000 miles and they have nearly all made something. Nothing like what they used to make but when I look there is something there.

 

Whether that has much of an effect by 10K miles I don't know but modern synthetic oils are so good that any slight tolerance imperfections could take a long time to wear in.

 

That is why we used to purposely use cheap 'running in' mineral oil to get things nicely bedded in then change the oil to synthetic which protected it from then onwards.

 

If anything I would say it is that which might delay the settling in of the engine especially if bores have glazed a bit early on etc etc

[ednmra]

I would recognise the "loosening up", if it happened, not as better mpg because I hardly take note of that.

To me it would feel like a noticeable increase in performance - not massive but a nice smooth bit of extra surge maybe.

 

However, I seem to recall reading a long time ago that modern engines were effectively "run in on the bench", i.e. at the factory, before they got anywhere near a car.

I don't know if this is the case but it would make sense to check out a complex item like an engine  before it disappeared under the bonnet and had all the  pile of other components smothering most of it ?  

 

Do they not still advise keeping within certain rev bands for the first 1000 miles or whatever, so the engine doesn't labour?

 

Having said all that there is surely bound to be a further bit of initial "wear", especially of any tight parts, as soon as the car starts working properly on the road.

But I'm sure this is nothing like that of years ago.

[Dr Zoidberg]

Mine improved noticeably over the first X000 miles. I can't remember exactly when but there was a definite change in economy, and yes I did have proper calculations on a spreadsheet rather than the trip computer.

[Auric Goldfinger]

Engines must be different to people, I've tried to get Mrs G loosened up after 32 years of marrage and she's still the same from day one, she's been serviced regular ( in her younger days ) she has been well lubricated always run on quality wine , passed all her mot's and had loads of work done under the marriage warranty. BUT, she's still the same, no extra miles per gallon

 

 

Any suggestions ?

 

AG

Edited 30 September, 2016 by Auric Goldfinger

[vRSAnt]

It certainly was true in the 'bad old days', when there were carburettors, contact breakers and things, but is much less of an issue nowadays with much tighter manufacturing tolerances.

I have never noticed any marked improvement in consumption on any new car I have purchased that I could not account for by improved driving technique as I learnt the characteristics of the engine/transmission.

However others will swear differently and I respect their own experience.

I actually hope it is true because I'm always striving for improved consumption.

Some days a car can seem to run better than others for no apparent reason, but it is so subjective, it could be just my mood?

 

A relative of mine in the UK works for a major car manufacturer and they make the jigs and patterns (whatever they are called?) for the engine assembly. During last summers very hot weather they were struggling to make them to the required very tight tolerances because the factory was not air conditioned and the metal expansion limited production to cooler periods of the day/night. Gives some idea of the tolerances they work to these days.

 

For this - we can thank the work of engineers and engineering companies like the relative you mentioned, also such as my father and his old firm 3M* by the way. (chemical engineer)

From the stories he's told me it is clear 3M was a lesser known cog in part of this revolution within tolerances on engines that you talk of - and also in a more easily wider understood issue of the failure rates of car paint jobs. He's also bored me to death with further talk of six sigma and percentages, lol.

I know people go on about it like its just part of the process, but its actually largely thanks to some clever engineers and radical improvements in processes

 

He mentioned that the failure rates on the paintwork side of processes at one point in one plant was as high as 9X % in a european plant - so you can imagine the savings when they could better refine problem paint areas rather than send a bad paintjob round to be sprayed the Nth time again....despite their improved paper costing so much more than the competitors saved some car companies a huge amount of money in the process.

 

http://multimedia.3m.com/mws/media/947018O/3m-abrasives-for-powertrain-components.pdf

 

*were also the first footprint on the moon left with 3M Fluorel brand Synthetic Rubber

 

I'll ask my father if you like. I'm sure he's probably more qualified to talk about this than anyone else unless equally qualified lol, and cuts straight through to a higher probility of talking about facts over opinions. Honestly, he does know his stuff.

 

I honestly didn't really notice any improvement in performance or MPG either on my Fabia1 diesel running in from new ( as I haven't owner the Octavia from new ) - but its a generic question not model specific ?

But that really is irrelevant as its not based on any kind of measurement, it well could could have some kind of difference, but I certainly haven't noticed if it has.

The only thing I did notice was its strong oil consumption in the first 10km but massively settled down, still top up a wee bit but probably due to minor leaks on the old Fabia

Edited 30 September, 2016 by vRSAnt

[Breezy_Pete]

Engines must be different to people, I've tried to get Mrs G loosened up after 32 years of marrage and she's still the same from day one, she's been serviced regular ( in her younger days ) she has been well lubricated always run on quality wine , passed all her mot's and had loads of work done under the marriage warranty. BUT, she's still the same, no extra miles per gallon

Any suggestions ?

AG

Maybe not getting filled up properly?

[tiv]

Well I used to think the overnight consumption drop was an urban myth until it happened to mine. Not sure it happened at any particular mileage but a marked change (for the better) in average fuel consumption calculated brim to brim. Same driving, same routes same temperatures and it has not gone back to previous levels to-date.

 

Seems like it was just a touch overfuelled to begin with. Not an unreasonable thing to do with a new engine IF it were the case. If they can program a defeat device into the system, not particularly out-there as a possibility either.

 

 

I'd second that - I did observe a very noticeable drop in avg fuel consumption in the 1.4TSI MkII I was driving before this one. It happened around 10k kms / 6 months.

[Auric Goldfinger]

Maybe not getting filled up properly?

 

I'd thought of that Wino, do you think the nozzle is possably to big therefor Mrs G is not getting the correct level of unleaded

Edited 30 September, 2016 by Auric Goldfinger

[vRSAnt]

Going back to even the days of G Plate Granadas they never did an initial running in "oil change" and at 1k it became just a "nut and bolt" service check.......rather than an oil service.

 

Even then the old 60's esque problem of wear i.e. iron filings on magnetic sump plugs, at that time onwards was eliminated with improved engine surfacing processes

 

So coming from the industry expert in abrasives whose also old enough to have remember running the really old cars as an engineer ( not me my father!) - and also spent much time in Skoda factories also by the way - says no there shouldn't be really that kind of loosening up you are describing.

 

I totally agree with Gabbo's post any other suggestion is going back to past understanding of engines which I'm afraid is now misunderstanding.

 

An engine isn't ice cream in a bowl.....they are very carefully toleranced metals dressed down with micon abrasive precision.

[neiln]

I bought my vrs tsi in june 2014.  over that first summer I would regularly drive London to Chester and back over a weekend.  Sure traffic and weather conditions varied one week to the next but there was a clear trend of increasing mpg until late spetember.  When the weather cooled the mpg dropped but it never dropped quite as low as it was when new, and when it climbed the following summer it was a little higher again.  Car is now about 15k miles and I get 30 to 40 miles more from a tank of fuel than i did at first, on that sort of London-Chester-London run.  SO I'm a believer in loosening up.

[flybynite]

Going back to even the days of G Plate Granadas

 

I was thinking you were talking about the 'G plate' previous to that, but they didn't make Granadas back then 

 

....they are very carefully toleranced metals dressed down with micon abrasive precision.

 

....then they shouldn't use oil, should always have oil pressure and never let go

 

How I wish that were true.

 

Things have certainly moved on, but they are not that different

[Wakey]

Going back to even the days of G Plate Granadas they never did an initial running in "oil change" and at 1k it became just a "nut and bolt" service check.......rather than an oil service.

 

Even then the old 60's esque problem of wear i.e. iron filings on magnetic sump plugs, at that time onwards was eliminated with improved engine surfacing processes

 

So coming from the industry expert in abrasives whose also old enough to have remember running the really old cars as an engineer ( not me my father!) - and also spent much time in Skoda factories also by the way - says no there shouldn't be really that kind of loosening up you are describing.

 

I totally agree with Gabbo's post any other suggestion is going back to past understanding of engines which I'm afraid is now misunderstanding.

 

An engine isn't ice cream in a bowl.....they are very carefully toleranced metals dressed down with micon abrasive precision.

Hey ant, the Ice cream was an analogy to show how friction decreases - I wasn't comparing it to an engine loools

 

Before I set up my business I was employed within the automotive manufacturing industry and I'm a chartered mechanical engineer (CEng IMechE)

 

No matter how close tolerances are observed there will always be a degree of bedding in over time. Always.

 

Like your dad says, the early days when component manufacturing was far less well controlled (before six sigma and CI) then the rate of wear and degree of swarf found in the oil was far more prominent. Also engines were ready for a rebuild well before 100k miles. This is attributable to poorer oils (again with less control over production quality and consistency) and greater variability and size of manufacturing tolerances.

 

With the rise of digital control and measuring systems and the introduction of the Japanese manufacturing and quality programs (5S, Poke Yoke, Statistical Process Control, FMEA etc etc) things have improved dramatically. These techniques are applied from everything to incoming raw materials, component suppliers, manufacturing machines and the whole workforce and suppliers are on board. 

 

The whole point of these systems is to reduce waste, reduce cost (from suppliers) reduce defects, increase consistency and reduce tolerances.

 

Getting to the point, as part of these rigorous systems comes a huge degree of predictability with engine and component longevity. Engines are bench tested to check the power output, heat cycles and many other things and come off the bench with a very very tight degree of accuracy. As a result, when compared to older engines then new ones do wear far more slowly, are within spec right from the off and can have a finite predictability of performance and longevity (based of fixed assumptions of oil grades, fuel grades, servicing schedules etc)

 

So when using visual observation yardsticks are used then new engines are 'run in' from the off and do meet o/p requirements and do appear to not need bedding in - they don't 'need' to bed in.

 

That said, tolerances are tolerances that allow for heat expansion, oil degradation, fuels, usage characteristics. Metals do run extremely closely in the engine and there will always be a point where an engine enters a sweet spot. It's the life cycle of anything manufactured. 

 

Older engines needed running in where new ones don't; New engines will bed in and gradually enter an optimum condition but due to oil quality and far better tolerances this takes many thousands of miles rather than maybe one or two thousand. This is why there is such debate from owners who have seen or noticed little and those who have seen an decrease in fuel consumption or increase in performance. Although tolerances from new are super super tight, they are tolerances; +/- from 0 and as a result there will always be a degree of variability of engine performance and the rate of wear or improvement.  :sun:

[mangham54]

Take into Consideration the change in average outside temperature between points.

Air temperature and general climatic conditions has a significant effect on the density of air, which the engine measures and provides the corresponding amount of fuel to. Turbo engines are even more susceptible to this due to the air measuring devices.

So if the car was new and in 21*c ambient and you are now comparing to 14*c ambient you will notice an effect in power.

Efficiency will partly be down to the engine being able to get there quicker and you adjusting your driving style to meet the new characteristics of the engine&car.

Given the long bench run-ins cars now have, the breaking in concept is a little out of date.

Remember the days of the 1k first service.

[countryboy]

I have noticed this on my previous Octavia (140bhp TDI) and my current Yeti (170bhp TDI). Consumption, especially on the Octavia decreased a bit at 10,000 and 20,000 miles. Loosening up of an engine is something of a misnomer in today's context. However, no matter how tight the tolerances may be there will always be allowances in a manufacturing process. What seems to be happening is something along the lines of harmonising of the components, in other words as they are used they bed into one another to provide the maximum efficiciency. This could take some time and occur not only in the engine but also in the transmission hence giving the feeling that the engine is loosening up.

Ian

 

P.S. Auric, may be the answer to your problem is to get a trade in? A diesel one which will take a wider nozzle when filling up too!

[Orville]

I am unsure whether mine ever really loosened up. It still feels tight after 20K miles.

 

However, fuel economy steadily improved over the first 4K to 5K miles, as can be seen within my economy logs below.

 

 

Edited 1 October, 2016 by Orville

[Gerrycan]

I do record my consumption but only in Fuelly, because consumption is what it is and like Orville's excellent data shows,  mine is also all over the place depending on the type of journeys undertaken and who is driving the car (time of year etc etc etc).

 

What I like to do is establish a couple of datum points using the instant consumption display and reset of current trip.

So for my current mk3 I have got a local, 2km stretch of flat urban dual carriageway with a 60kph limit and low traffic. When I first got the car I found that maintaining an indicated 60 kph  (which I now know is an actual 57kph) in 5th gear gear (manual) it averaged out at 3.7L/100. After 27k km I think it is averaging 3.5L/100 at that speed.

 

My other datum point was at our speed limit on the open highway and at an indicated 116kph (110 kph true) then I got and still get 5.7L/100.

 

At the higher speed most of the fuel burnt is pushing air out the way so for any real improvement in consumption to show it would take quite a high reduction of friction in engine and transmission to manifest itself.

At the lower speed then engine/transmission friction is a far higher consumption factor and any improvements from bedding in should show itself more clearly.

 

The apparent improvement of just 0.2L/100 is not enough to convince me there has been a significant lowering of friction and may just be that I now drive the car better.

 

I do still check both datum speeds when conditions are appropriate but it is principally to make sure there is no deterioration indication there might be engine problems.

 

By the way I am really enjoying reading the contributions so far, good informative stuff, and I am sure that there are some engines that benefit from wearing in (before they wear out) so I am really just relating my experiences and methods.

[Breezy_Pete]

I'm intrigued by the notion that engines are 'bench tested' before they get into a  car.  I can imagine a new design of engine being bench tested extensively, but I'd be frankly amazed if each and every individual engine that gets built is run at all before it gets into the car. It would be vastly expensive, slow and inefficient to do so, wouldn't it?.  Anyone have any current knowledge/references to educate me?

[vRSAnt]

I was thinking you were talking about the 'G plate' previous to that, but they didn't make Granadas back then 

 

 

....then they shouldn't use oil, should always have oil pressure and never let go

 

How I wish that were true.

 

Things have certainly moved on, but they are not that different

 

Prefix letter G on the MKIII - definitely within their production years

 

Modern cars (particularly 4 stroke petrols) don't normally burn oil internally through the combustion engine when new, or even within the first 50-100K unless there is something wrong with them beyond their normal design contraints

( and you need to generalise about all engines behaviour, you can't just take into account one bad luck example).

 

Going back to earlier years and cars like my father used to have, this is far from true, they would all tend to smoke a bit and tolerances were far poorer.

So yes things definitely are very different.

[Ootohere]

Great theory and sometimes true.  Many get that complimentary litre of oil with the new car and never use it.

Well not until they get a warning light and they have to, then go buy some more.

 

Others just know a top up is required on occasion.

Those that never need to add oil between services obviously do exist.