Longines Ultra-Chron

[Ralph Porter]

I'm a pocket watch person in unfamilier territory and I need some help.

The Longines watch in question is an automatic, pictured below. The movement is caliper 431, 17j, adjusted 3 positions, marked Longines Watch Co. Swiss, and the serial no. is 14695922.

I'd like to know about when it was made and if is it relatively common or uncommon. Also I've heard that during a brief period Longines used rolex movements in some of their watches. Certainly I'd like to know if this might be one.

Thanks,
Ralph Porter

 

[lamarw]

Check your recent NAWCC Bulletins. I have all mine packed for moving, but I do recall a rather detailed artilce covering Ultra-Chrons specifically and other High Frequency watches like the Girard Perregaux.

 

[Ralph Porter]

Alas, I've been a member for less that 2 years and have given away several issues to entice some potential members. :bang: As you suggested I checked the remaining issues I have but didn't find the article.

So, I'm still hoping a knowledgable wrist watch person can provide some information.

Thanks,
Ralph

 

[Poincon]

The article was in the December 2007 Bulletin which I recommend to you if you have a real interest in the L431. From the movement number, your watch was more likely than not made in late 1967 or early 1968. Production started in December 1967. The L431, itself, was made between 1967 and 1975 and 520,000 pieces were made. I don't know if that makes it common or not; IMHO I think not. Despite the name, it is not a certified chronometer as there were only very few of those submitted in 1969 and the dial markings reflect the certification. Notwithstanding, the L431 was capable of +/- 1 sec per day, which is beyond the range of the chonometer standards, even under the pre-1973 standards; IMHO that is what the name means: "ultra" beyond the range of, and "chron" chronometer. If the movement was marked as you stated, it is a Longines in-house design. I have never heard of Longines using a Rolex movement but would be interested in any information you have on that topic. Frankly at the time your Ultra-Chron was made, Longines movements were head- and-shoulders above the competition! If it is an L431, it has an oscillation rate of 10Hz or 36kbph. A reduced oscillation rate version, the L6651 was produced between 1972 and 1976 (and likely in a smaller quantity) with the now familiar oscillation rate of 28.8k. There is no external, visual sign to tell which it is; this information is actually printed on the movement. However, the ticking is markedly discernable and therefore, working versions are easily and quickly identifed by even the novice's ear.
I think that answers your questions. If you have additional questions I will try to answer them for you. Enjoy your watch.

 

[Ralph Porter]

Thanks Poincon, I really appreciate it. That's great info

Actually it belongs to a friend who thought I might know about it but obviously not! I wish we'd made a pic of the movement when it was open, but we took it to another guy who had the proper wrench. The number 431 was enclosed in a box on the movement so I assumed that was the caliber. As for the Rolex connection, I thought it might be a fable but since some local WW enthusiasts mentioned it I decided to ask.

I'll see if I can find a copy of the 12/07 Bulletin to borrow too.
Thanks Again,
Ralph

 

[Poincon]

Ralph,
Here is a picture of the L431 movement:
http://www.nawcc-mb.com/pictures/file-DSCN4016.JPG
IMHO, it is quite nicely finished for the era. The "431" in the gold box inded is the caliber number.

FWIW, for a time (that only ended in the 1990's) Rolex used Zenith chronograph movements There was a time (at the very begining) when the movements for Rolex were made in the same factory as Gruen movements. I have no indication that Rolex ever sold its movements to anyone.