Introduction & request for help

I have just registered in the forum. I am a Mexican national living in Mexico City, 44 years old and an attorney. Back in December 2003 I purchased, new, my steel Overseas chronometer model 42042/423A, case No. 712204, movt No. 730146, dial 8722 and bracelet 423.

I have several questions I would be grateful if you could help me answer. The date in my watch changes at 3:00 am. Is this normal? or should the date change at 0:00 hrs.? Should the date change be gradual or quick? Is my movement a 1310 or a 1311 ref.? Can anyone let me know the date of manufacture? How often should the watch be serviced?

Thank you in advance for any information you can provide.

Best regards,


Welcome Rugger! Your watch has the caliber 1311 which is
05/15/2007 - 14:45

an evolution of caliber 1310. The 1311 is an evolution of the 1310 as to make it more strurdy for a sports watch. The main difference is the difference in thickness 2.98mm for the 1310 and 3.28mm for the 1311. The case of the watches with caliber 1310 and 1311 are the same.

As for the date change I'll let other OS owners reply as I don't own one.

Are you sure?
05/15/2007 - 16:43

Are you sure that it is the cal: 1311? Due to the date-change it sounds more like cal: 1310.


From Eric Edelmans review: "Those of you who have read the whole review will notice that my previous Overseas used a caliber #1310. The new iteration is still based on the Girard-Perregaux 3100 caliber, but Vacheron has made additional changes. These include a revised rotor and calendar system and a slightly reduced size so that the newer military style dials will fit properly. If my memory serves me correctly, my previous Overseas changed it's date gradually, from around 11:30 to 12:30. In setting this new watch, I've noticed that the date change is now immediate, and it occurs right around midnight, which must be the new calendar system at work".



That's what VC tells me according to the ref n°. Furthermore the
05/15/2007 - 16:54

size of the movement did not change when going from 1310 to 1311 contrary to what is indicated in the article.

Re: That's what VC tells me according to the ref n°. Furthermore the
05/15/2007 - 21:56

Thank you both for your help! Best regards.


Np! Its a great watch you got - take care of it. (nt)
05/15/2007 - 22:23


OS 1 1996 is ca. 1310
03/31/2016 - 20:25

According to Vacheron Constantin, my OS-1, built in 1996 (Happy 20th!) is ca. 1310. I'm working to find out what year the calibre changed from 1310 to 1311. (Request into Vacheron Constantin Archive Dept.)

Re: OS 1 1996 is actually ca. 1311
04/23/2016 - 15:15

In a revised response from Vacheron Constantin when I asked them when the ref. 42040 changed from 1310 to 1311, they told me that mine was a 1311--after initially telling me it was 1310. So, I wonder if Vacheron Constantin ever actually used the 1310 in an actual watch. I don't think so, and because they had to do considerable work on the Gerard Perragaux 3100 (its base) to get it to work up to Vacheron Constantin statndard. So while the redesignation of the Gerard Perragaux 3100 to Vacheron Constantin 1310 may have been for labeling purposes, I cannot find a Vacheron Constantin that actually have the VC 1310.

In once (forgotten) reference I saw, Vacheron Constantin got the bugs out of Gerard Perragaux 3100 before Gerard Perragaux did!enlightened

Re: Re: OS 1 1996 is actually ca. 1311
04/24/2016 - 20:24

Hi Bill, the data points you use to make conclusions may not be enough.

One of the very first reviews I read online about the 1st Gen. OS was by Eric Edelman in 2001.

You will see that his frist OS had a Cal. 1310 and his second OS had Cal. 1311.

The reference you are talking about in your last sentence possibly comes from "The Decay of an Angel" Part III by Carlos Perez on Timezone in 2002 (it can still be found in the TZ Archives section)

1310 or 1311?
04/29/2016 - 11:17

Hi Dan,

It's hard to know. Here is what I got from Vacheron Constantin:

#1 Response:


Dear Dr. Sanders,

 Thank you for the message. In regards to your inquiry, the movement caliber for the Overseas 42040/423A-8, serial number 677714 is Caliber 1310; which is an automatic movement with 27 jewels. Please feel free to contact me if I can be of any further assistance.  As always, I remain at your service.  Best regards, Melanie Vacheron ConstantinNorth America Concierge Service ----------My Response---------- Cher Madame Concierge Melanie,

Thank you (and the archive department) for all of your help with my Vacheron Constantin Overseas' identity.Were I to purchase another Overseas 42040, I would like to know what year that Vacheron Constantin changed ébauches from the caliber 1310 to caliber 1311. (My 1996 houses a cal. 1310.) I realize that this is a difficult query and the Archive Department may not have that information. The reason I ask is that I understand that the caliber was changed to make it a bit more sturdy for the “sport” type of watch that is the Overseas design.I realize that they may not be able to answer this question, but that’s Ok if they do not have that information. They (and you!) have been a wonderful help already.Bien sincèrement,Dr. W. Sanders

----------Second Reply----------

Dear Dr. Sanders,

I hope you are doing well.Our Technical Department responded today regarding your question concerning the caliber 1311.  They have confirmed Vacheron Constantin started using the 1311 caliber in the Overseas 42040 when it was launched in 1996.We remain at your disposal should you need any further information.Best regards,MelanieVacheron ConstantinNorth America Concierge Service--------

So it's hard to say. Eric Edelman may have got the "wrong" information from VC--clearly it depends on which response from VC one chooses to believe. For me, it's a delicious mystery! For now, though, I'm going with the 1311 "history."

Re: 1310 or 1311?
04/29/2016 - 13:28

Choosing which version of history is always up to each individual.  

But you will notice that Eric observed a change in how/when the date changes, which is one of the differences between 1310 and 1311.

I've also owned 2 versions of thr 1st Gen. OS (previous one with the silver dial and my current one with blue dial).  My old one changed date more slowly over  time.  My current one changes much faster at midnight.