# IWC Modified Movements Explained



## NightScar

There doesn't seem to be some clear answer to what IWC exactly does when modifying the ETA/Valjoux movements but this article briefly discusses the few things IWC does, more specifically the Valjoux 7750 movement. The article is a bit old, circa 1998, but I believe the method still hold true. It is still a good and very interesting read nonetheless.

http://www.pmwf.com/Watches/Series/IWCGSTChronoBeachHuaHin/UhrenjournalIWCUseOfBaseMovements.html



> _The following is a translation from the Uhrenjournal, 20 November 1998, an Austrian watch publication_
> 
> *Question:
> How can a fine watch manufacturer such as IWC, state, that despite using an ETA-serial calibre, it renders a base ETA movement into a new, superior IWC movement? For example, what changes are made to an ETA-Valjoux 7750 calibre before it is built into an IWC chronograph?*
> 
> _Many watch manufacturers purchase their calibres from the serial base calibre manufacturer ETA. ETA offers a wide variety serving most needs. However, for many watch collectors seeking limited production calibres, this is just the reason to avoid buying a watch with an ETA movement. What if a renowned manufacturer such as IWC Schaffhausen would use the actually very good and tested ETA Valjoux 7750 for its chronographs, after undertaking numerous modifications? What speaks against the ETA movement? Actually, only the fact that it is widely used and therefore not very exclusive. In turn, what speaks for the ETA movement is that, due to the high production, it is a mature and technically impeccable movement. There are no "infant illnesses" and it is constantly developed further. Why therefore should IWC overlook the best serial chronograph-movement? Obviously, there are other alternatives, however, from an economic and technical standpoint, the decision for the Valjoux is guaranteed to be the right move.
> 
> Now, what does IWC do with this calibre, and why do they treat it as if it were their own movement? The explanation is pretty simple: IWC purchases the best serial engine and undertakes on that basis the best possible engine tuning. You could say that IWC does what AMG does with Mercedes engines, Alpina with BMW or Abt with VW or Audi engines. Serial engines are used, which in turn are tuned and optimized with the best experience available.
> 
> In the case of the Valjoux, the calibre is only bought in its components, never readily assembled. In addition, only the best possible version is purchased - the so-called Chronometer version. When the components arrive in Schaffhausen (IWC's factory location) there are first of all checked by eye, and then randomly checked in detail. Some components of the original ETA calibre are immediately eliminated and are never used by IWC. They are replaced by usually more expensive and better ones.
> 
> The entire escapement is a good example. It is ordered separately with different, more exact technical IWC specifications and is only fitted into the calibre at the end of the assembly. Some changes take place even earlier: For instance, all metal bearings of the Valjoux 7760 are replaced by jewel bearings - the Valjoux 7760 (same as the 7750 but in the handwound version) is the basis for the Portugieser Chronograph movements. There is an IWC expert whose job it is to extract by hand all metal bearings from the supplied calibre and replace them with the more expensive jeweled bearings. This is an effort, which will ultimately significantly increase the longevity of the movement.
> 
> This exercise is futile in the version 7750 as it only comes with jewels. Instead numerous cogwheels are replaced. For instance, one is part of the winding mechanism, which ETA supplies with three holes in order that it can be worked on by machines and be transported by robot arms. As the holes are drilled, there is some metal, which is pushed over the surface - causing friction with the above-located bridge. Now IWC found out that it is precisely the position of these holes, which will cause fine metallic debris over time to accumulate. In the short run, such metallic debris is not a problem, however over a longer period such debris will cause problems.
> 
> Many more examples could be listed at this point, reaching far beyond the space allocated for this article. Therefore, let's come back to the escapement of the movement. Before the escapement is fitted into the movement, a specially trained, female horological expert (so-called regleuse) checks each hairspring for unevenness. How does she do it? Quite simple, she holds the escapement with a special device and turns it. Then she makes sure with her magnifying glass than the escapement unfolds in concentric circles. If not, she manually bends the hairspring to perfection. Again, this in an effort of which the value is only apparent in the sum of all efforts and is ultimately reflected in the accuracy of the movement. The pinnacle of all these tuning efforts lies in completely replacing the barrel. There are some many changes and modifications to the calibre 7750 leading to far lower power requirements of the movement. As a result the original ETA barrel is now far too strong for the modified IWC movement. A "weaker" IWC barrel brings about significant advantages. All moving parts suffer far less wear and tear because there are exposed to far smaller forces - again, this significantly prolongs the average life of an IWC movement.
> 
> It is not exaggerated if IWC makes the statement that it treats the ETA movements as if it were an original IWC movement. The numerous modifications and the great care, completely transform the original, mass-produced movement by ETA into another movement. ETA is not necessarily ETA as it is often falsely stated._


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## NightScar

Here's another article from 1998 on Calibre 32524:

http://www.timezone.com/library/comarticles/comarticles631681558435961807



> *IWC cal. 32524 in the Aquatimer and Facts*
> 
> Originally Posted by Time Flies on September 20, 1998
> Copyright, 1998, 1999, G. J. Buhyoff
> 
> _Well, I can see that it is time to post this. l wanted to wait until I had even more information about the sealing process used in the IWC Aquatimer and some additional detail about movement parts finishing...but, there seems to be enough argument and misguided thought expressed on the Forum to hasten this post.
> 
> First, Aquatimer uses an IWC cal. 32524 movement which is "based" upon an ETA 2892. It is NOT an ETA 2892 in the same way that the Valjoux 7750 in the Flieger Chrono is not a Valjoux 7750. Both IWC movements are BASED upon these two more commonly used movements. l don't want to restate what I and others have said over and over and over again. So, I will reference some important REQUIRED reading at the end of the piece.
> 
> Before, I itemize what I have discovered from my sources regarding the Aquatimer's Cal. 32524, let me note a few related thoughts. First, what movement should IWC have used in the Aquatimer? A JLC 889 base? I do not believe this would have been a good choice. The 889 is a bit too delicate and sensitive to losing adjustment without special external (to the movement) shock absorption (ala the Inegeniuer). The Aquatimer is designed to be tough sport watch that is intended to take a beating commensurate with its 2000 meter water resistance rating and its 3.2mm thick sapphire crystal.
> 
> So, what would you use? A tough reliable handwound movement? Yes, that might have been a good choice but the market is looking for automatic movements in all liklihood and a sport watch, especially one engineered for diving, likely demands an automatic movement. What other JLC movement would qualify for a sport watch? Think about it. What movement design, short of designing a new movement, fits the bill? Design a new movement? Boy, that would sure limit the sales of the Aquatimer since the price would be much higher due to the consumer having to absorb the cost of R&D and retooling.
> 
> The 2892 is used in wide range of watches and what does matter is that the design of the movement, while not particularly elegant to some, is a workhorse that has been around for a long while and improved over time (see reading below authored by Walt Odets). More importantis what HAS BEEN DONE to the stock movement, not the movement base or kit.
> 
> Secondly, l would like to quote my friend Michael Freidberg in a post he made -
> 
> "When I met with Renee Schwartz, head of service for IWC Schaffhausen, at the Basel Fair, l specifically raised with him thesubject ofIWC using ETA 2892 ebauches. He explained that IWC replaces most of the critical parts with parts of their own specification, including replacing the wheels with a stronger metal composition, and also the use of a longer mainspring for theoretically greater accuracy. When I met with IWC in Schaffhausen, l learned that IWC finishes its movements to its higher specifications and assembles all base movements from scratch -- even when they use JLC ebauches. A 2892 is really a design -- and there is nothing wrong with the design. If it is implemented with high quality parts, finished meticulously and assembled with painstaking care, it can be a very good movement."
> 
> Now, here is what I have found about the IWC 32524:
> 
> IWC uses a 2892 KIT -- not an assembled ebauche. They take this kit and replace parts or use parts of their own design to meet their own specifications for tolerance and strength. These include:
> 
> -the gear train
> -wheels and levers
> -mainspring and barrel
> -a 21 K gold mass is added to the rotor for winding efficiency
> -all parts are finished and assembled by hand
> 
> Is this a stock 2892? No. ls it based upon the design of the 2892? Yes. ls it likely to be a fine movement, given the finishing and the parts specifications used ( metalurgy and tolerances) used by IWC? Yes, definitely. Was it a smart choice for IWC? I think so, definitely. IWC has based their caliber on a tough, proven design but likely made it tougher and one with greater expected longevity due to the application of their specification standards, finishing and hand assembly.
> 
> Finally, I am always a little amazed that some people do not use the fantastic resources that are available via TimeZone including Jack Freedman's Escape Wheeling series, Walt Odet's Horologium pieces and the array of other archived posts as well as the posts on the Bulletin Board.
> 
> I strongly suggest you read the following related posts that will give further detail about the subjects I have spoken about in the post above. My research and the citations below ought to answer many of the questions you might have about why the IWC caliber 32524 is not really an ETA 2892, but rather a caliber BASED upon the ETA 2892. In addition, be sure to read Mycroft's post about IWC Titanium finish and information regarding the sealing system used in the Aquatimer_.


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## NightScar

Here's a quick pic of the modified Valjoux 7750 on the Pilot Chrono 3717.










If I understood German, then I could explain this much better, but here's the calibre comparison pics I found:


















Pics of the Calibre 37524 based from the ETA 2892-A2.


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## hpark21

Thanks for the articles.

Quite informative read. However, what is the future IWC's plan when faced with scheduled phase out of the ETA's ebauch "kit"?

Do they plan to purchase completed movement and discard most of it and start over? Are they going to do same thing the are currently doing with Selita's movement?


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## NightScar

To those who wants to read about the in-house movement in the 5001, click on the following link: http://www.thepurists.net/Patrons/Members/JackForster/iwc/iwc_revE.htm


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## NightScar

hpark21 said:


> Thanks for the articles.
> 
> Quite informative read. However, what is the future IWC's plan when faced with scheduled phase out of the ETA's ebauch "kit"?
> 
> Do they plan to purchase completed movement and discard most of it and start over? Are they going to do same thing the are currently doing with Selita's movement?


I'm pretty sure they already have a plan for that occasion but I do not think it has been revealed as of yet. I'll look around and see if I can find any informations and I'll get back to you.


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## BenL

Good stuff. :-!


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## spluurfg

hpark21 said:


> Thanks for the articles.
> 
> Quite informative read. However, what is the future IWC's plan when faced with scheduled phase out of the ETA's ebauch "kit"?
> 
> Do they plan to purchase completed movement and discard most of it and start over? Are they going to do same thing the are currently doing with Selita's movement?


They could just buy finished movements and disassemble them... more expensive but market distortions could make ebauches only marginally cheaper than finished movements.


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## Sgian Dubh

Given that IWC develops in-house movements, I think they might move that way, which will be nice from a horological point of view but bad from a pricing point of view.

I suppose they could just drop ETA movements in untouched, but that doesn't seem to be the IWC way.


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## NightScar

As much as I would love to see IWC go to an all in-house movement company, I would hate that it won't be affordable to most. I mean their cheapest in-house movements starts at what, $5,600 with the Calibre 80110 on the AMG Ingy? I guess it's not bad but I do not want to see IWC watches starting at that price, it would get rid of too many beautiful watches in their line-up, ie: Pilot, Spitfire, almost all chrono watches, etc...

Since I mentioned the 80110 movement, here's a quick article on the subject:

http://www.p178host.com/iwcgallery/Ingenieur2005/Ingenieur2005.html



> *Here it is. The new Ingenieur family.*
> 
> IWC´s new flagship is introduced in three basic references: a regular model (reference IW3227), a mid-size model (reference IW4515) and, for the first time in the Ingenieur line, a mechanical chronograph (reference IW3725). The line-up is completed by two "Edition AMG" variants with Titanium cases.
> 
> To each his own - as we will see, all of them are special.
> 
> Starting with the regular model, on first view the Ingenieur Automatic is a very modern approach.
> It is a large watch representing design elements known from the reference 1832 "Jumbo" model, such as an integrated bracelet, a large bezel featuring the typical five holes and a clear legible dial. Thus it is easily identified both as an IWC Ingenieur and bearer of a real heritage, while being new and innovative at the same time. This combination is not easily achieved by every recent successor of a well known model and while the Ingenieur clearly is not a watch for everyone, personally i regard it a very successfull bridge between tradition and innvation. Therefore odds are good the design will seduce not only followers of the post-1976 Ingenieurs, particularly as large watches, such as the "Portugieser" range, are nothing new in the portfolio of IWC.
> 
> The dimensions of 42.5 mm in diameter and 14.5mm in height certainly cater the current preference for larger cases and a decidedly masculine look.
> But the Ingenieur is not intentionally large only; the external qualities do speak for themselves, including a solid three-part stainless steel case with integrated IWC metal bracelet, both screw-down back and crown and a sapphire glass bearing antireflective coating on both sides.
> 
> It would not be a true IWC watch if it were not well in line with IWC´s philosophy and traditions in the field of sports watches.
> 
> And thus it is no surprise to learn the large case of course offers hidden values justifying the size, even when considering the "heart" of the new Ingenieur measures 30mm in diameter only.
> 
> 
> 
> 
> 
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> The new Ingenieur Automatic offers traditional key features of the Ingenieur range; first of all it is highly protected against magnetic fields, which are apt to influence the proper function and accuracy of the movement.
> 
> This antimagnetic shielding is achieved by use of a soft-iron inner case, which is typical for Ingenieur models of past 50 years. Like early models of the Ingenieur range, the antimagnetic protection of the new Ingenieur Automatic does include the dial and thus forms a "Faraday cage", which guarantees protection against magnetic fields of up to 80,000 A/m (amperes per metre). This result considerably surpasses the required Swiss standards for antimagnetic watches of 4800 A/m.
> 
> In addition, the case and crystal is water-resistant up to 120m depth and, much like the famous MK XI model, low pressure (which can cause displacement of the crystal in case of a drop in air pressure).
> Therefore it can and should be noted the casework of the Ingenieur is unusually elaborate and almost understated, with many of the features hidden behind the solid back. It is a piece of classic Schaffhausen craftmanship and engineering. And it is a substantial piece: the weight of the new Ingenieur Automatic including the bracelet of 216 gramms does not make this a light watch.
> Nonetheless, the true value is the new movement caliber 80110, representing a first for IWC and the watchmaking world in several aspects.
> 
> *Inner values: IWC manufacture caliber 80110*
> 
> 
> 
> 
> 
> 
> 
> 
> The highlight of IWC´s new flagship certainly is the new manufacture made caliber 80110 automatic movement.
> 
> The new caliber 80110 does represent a major achievement for the Schaffhausen brand in many aspects. Historically, it is the first newly developed manufacture movement with less than 37mm diameter since four decades ago. And it is the latest family member in a line of movements which made IWC famous, with it´s brethren, such as the famous caliber 8541, frequently referred to as some of the technically best movements ever made.
> 
> As we will see, the new caliber 80110 does follow this tradition; but rather than being a retro-design, it offers some new and surprising solutions including the use of new materials.
> 
> On first view, IWC´s latest addition seems to be surprising similar to previous movements. This visual relation is probably not uncalled for; according to the details known so far, it is designed to be a sturdy, reliable, effective, service-friendly and long-term accurate micro-machine.
> In this the new caliber 80110 follows the same principles as earlier creations by the Schaffhausen brand, which may be regarded corner stones of the brand´s fame.
> 
> The new caliber 80110 again makes use of Albert Pellaton´s ingenious invention, the famous winding system with rockers and pawls that is know from earlier movements by IWC, but recent additions like the 5000 caliber family as well. The Pellaton winding is widely regarded as a most effective and reliable bi-directional winding system; 50 years of use do speak for themselve in this regard.
> 
> 
> 
> 
> 
> 
> 
> 
> As we see, a key issue during development was shock protection and as we will see later, it is achieved by unique solutions. IWC claims the result to be the "definite improvement of the integrated shock-absorbing system" and the new caliber 80110 automatic movement to come with "the most effective protection against jolts and jarring".
> 
> Another familiar feature is the special shock protection by means of a flexible rotor bridge; the rotor bearing rests on a "S-shape" bridge which allows bending in case of lateral and horizontal shocks. This is achieved by mounting the rotor bridge with two attachment points only; this way, the S-shaped "arm" positioned on the opposite perimeter remains flexible. Again, this is a construction known from early IWC automatic movements and it´s proven to work exceptionally well.
> 
> 
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> 
> 
> 
> 
> 
> But the visual similarity ends on closer view.
> The first major difference is, much like the case, the size of the movement. A comparison may clearify:
> IWC last manufactory-made automatic caliber 8541 was measuring 12.5 ligne (28mm) in diameter and 5.9mm in height; the new caliber 80110 does exceed these dimensions, measuring 30mm in width and 7.20m in height.
> 
> 
> 
> 
> 
> 
> 
> 
> And again, the additional space does not remain unused.
> Apparently all parts are significantly thicker than their predecessors; an aspect usually indicating a more sturdy construction. But it would not be IWC to increase the mass only, without caring for the details; an example is the re-designed rotor, which now is crafted with cut-out sections that increase flexibility in case of severe horizontal shocks.
> 
> In this regard, a magic formula is Delrin®.
> DuPont Delrin® acetal polyoxymethylene (POM) resins are highly versatile engineering polymers that bridge the gap between metals and ordinary plastics; a sturdy yet flexible material known of applications such as break pads for inline skates.
> 
> IWC went out of the box and placed "bumper pads" underneath the rotor; this way, the flexible rotor weight may touch the movement plate and bridges in case of extremely severe impacts on the watch case, but due to the use of the Delrin pads no harm can happen to the plates themselves.
> 
> It is an application much in the spirit of IWC; seemingly simple and most effective. It is the first application of this kind in any watch movement and promising to work extremely well; a material sturdy enough to be used as a break pad is likely to withstand the forces in a watch movement even more easily, while being flexible enough not to scratch any other parts. From my perspective this makes a perfect addition to the especially shock-protected layout of caliber 80110 and to my understanding it is an inventions that really makes a lot of sense, with some real value added for any future customer.
> 
> The only downside - hardly any owner will be able to see the new pads, as they remain invisible in the assembled movement.


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## Kiwi Mac

Very interesting - thanks!

I have to say that the Ingenieur is not my favourite of the IWC stable by a long chalk (just a personal taste thing) but there is no doubt it is an excellent watch.

I saw one post somewhere where the very good point "why should an in-house movement necessarily be any better than a bought-in alternative?" was made.

If you take a movement from ETA that has proven reliability and accuracy in the standard form and then re-engineer it to be even better, that seems a very sensible way to proceed.

A bit like taking say a Ford V8 and then having Carroll Shelby re-building it with top notch performance parts: the original was fine - but the Shelby is WAY better!


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## Kiwi Mac

I found this interesting piece on Timezone (my bold):

"A few observations:

As far as I am concerned it's very sad that even with the huge slew of new movements that have been introduced during the 3135's past two decades of continuous use and refinement, *there still aren't too many challengers to the Rolex triple crown of accuracy, reliability and durability - i.e. its toughness - for example, its ability to withstand the abuse of everyday life that most active people, both men and women, would hurl at it, and still keep on ticking. And not just keep on ticking, but to continue doing so accurately too. The only ones that come to mind are the ETA 2892-2A, the ETA 7750 (including their numerous variations and incarnations) *and possibly Omega's new caliber 8500. But unlike the first two movements, the latter one, notwithstanding the fact that it is their 3rd generation of Dr. George Daniel's co-axial escapement, doesn't have the advantage of over 20 years worth of use, abuse and refinement, so it's still an open question as to its long term reliability. So in my opinion, that leaves only two serious contenders to Rolex's 3135 throne. Of course I would be remiss not to mention Rolex's own caliber 2235 for its ability to match the three men's movements. Which is an astounding achievement given the fact that this is a lady's movement and a lot smaller in diameter and volume than the aforementioned ones.

Initially I was also going to include the Zenith Caliber 400 in this small selection above, but ultimately decided against it because although it's virtually on a par with the ETA 7750 in most respects, unfortunately unlike the latter, it is only available in various chronograph options.

I'll be the first to admit that none of these movements will win any prizes for their aesthetics, or their level of decoration. Plus there are other movements that I have mentioned before that can match these three in terms of accuracy, but I haven't included them here because they are too fragile to be classified as tough movements, or haven't been around long enough to prove their long term reliability. A perfect example is the JLC 889. An excellent, accurate and reliable movement when serviced by competent watchmakers, but not known for its ability to withstand abuse Then of course we have a few Seiko and Citizen movements that have an outstanding reputation for their toughness and reliability, but most of them fall short in the accuracy department, and one is fortunate if they are accurate to better than +- 15s per day. As a note of interest that standard was more than acceptable for certified COSC chronometers in the 1960s, but most people today expect better, having been spoilt by the standards of their thermo-compensated, atomic clock adjusted quartz watches. And so the COSC have raised their standards accordingly.

And the winner is&#8230;

*Of these three movements which one do I like the best? If accuracy is your only criteria, then it doesn't matter which one you choose as there really is virtually no difference between them in that regard. Sure some individual movements might time out marginally better than others, but overall the differences in time keeping between them is insignificant. All three are capable of exemplary accuracy in all six positions, and do so with a minimum of variation and loss to the balance amplitude. More importantly, they should provide excellent accuracy and reliability under real world conditions too.*

As for me, please keep in mind that no movement is perfect and that they all have their strengths and weaknesses. *Having said that though there is absolutely no question in my mind, that I prefer the ETA 2892-2A over the other two.* Okay, so it's been around almost half a century and in many ways isn't as sophisticated as the Rolex - no Breguet hairspring, or Parachrom hairspring material etc - but during its long lifetime in its best available chronometer version, it has proven itself to be an exceptionally accurate, reliable and tough movement. Its two main advantages over the 3135 are that it's quite a bit thinner, only 3.6mm thick versus 6mm, and has only one major weakness - the inefficiency of its automatic winding system, as I mentioned in my earlier review of it. While good enough for most reasonably active folk, it is not efficient enough for those people, young or old, who lead a sedentary lifestyle. "

(See the full article at http://www.timezone.com/extras/200903313583)


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## Sgian Dubh

I agree with most statements in that article. The only problem is that I think the author disregards Seiko movements too quickly. There are some Grand Seiko and certainly Credor movements that best Rolex and other Swiss movements in the accuracy department. I've also heard that they're quite rugged.

Also, I didn't know Citizen made automatic movements. I thought they were all quartz these days. That said, I wouldn't mind getting my hands on a Citizen Chronomaster -- the most accurate watch in world!

Edit: My mistake, I forgot about the Miyota movement.


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## NightScar

I think we need to get this stickied. There seems to be a lot of questions regarding the movements and we can just compile all the informations we find on IWC movements here.


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## FrogmanFreak

very interesting thread.


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## iwantagmt

Very interesting...does the movement still make the "whirring" sound of the regular 7750? Does it still wind in only 1 direction?
Thanks!


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## skele

hpark21 said:


> Thanks for the articles.
> 
> Quite informative read. However, what is the future IWC's plan when faced with scheduled phase out of the ETA's ebauch "kit"?
> 
> Do they plan to purchase completed movement and discard most of it and start over? Are they going to do same thing the are currently doing with Selita's movement?


If they are replacing all the critical parts anyway, why not just replace the non-critical parts as well? Should be easier to replace the non-critical parts than the critical ones and no one is stopping them from doing it.


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## red_wagen

skele said:


> If they are replacing all the critical parts anyway, why not just replace the non-critical parts as well? Should be easier to replace the non-critical parts than the critical ones and no one is stopping them from doing it.


Because there are no positive effects in doing so and just adds cost.


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## phatonycmu

Deleted my previous post, just realized that they moved to a competitive provider of movements for their Portofino line at least. It would be good to know how this will impact ownership etc... I'm hoping the answer isn't "only time will tell."


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## Michael Schott

phatonycmu said:


> Deleted my previous post, just realized that they moved to a competitive provider of movements for their Portofino line at least. It would be good to know how this will impact ownership etc... I'm hoping the answer isn't "only time will tell."


I'm not sure what you mean by "they moved to a competitive provider of movements for their Portofino line". AFAIK ETA still provides the movements for these watches except for the in-house 8 day movement.


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## warren t

Must corect the statement (first use) of non metalic material to support rotor under shock....it was used in that
great tool watch movement Lemania 5100 since 1974.


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## BIC

I am interested in the new IWC Pilot Worldtimer (Ref. 326201) with Caliber 30750. I can't find any information about the base/origins and in-house modifications. Anybody have any info? Thanks.


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