Poljot 3133 vs. Valjoux 7734 (by Lysanderxii)
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Thread: Poljot 3133 vs. Valjoux 7734 (by Lysanderxii)

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  1. #1
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    Poljot 3133 vs. Valjoux 7734 (by Lysanderxii)

    Полёт 3133 versus Valjoux 7734 (with pictures, lots of them)

    Note: this is an excellent article written by Lysanderxiii.
    I have also directly uploaded all the pics on WUS (to obtain a backup archive if something goes wrong with one of the two image hosts), they are too precious.
    Lysander, thank you very much for this milestone!
    ----------------------

    by lysanderxiii on Mon Jan 12, 2009 2:36 am
    To celebrate my 1750th post, will examine and compare the Полёт (Poljot) 3133 and the Valjoux 7734.

    First the technical details of both:

    The Poljot 3133 is a 23 jewel, cam controlled, chronograph, lever movement operating at 21,600 bph. It has a running second dial at the 9 o'clock position, a 30 minute counter sub-dial at 3 o'clock, and a sweep second counter mounted centrally along with the timekeeping minute and hour hands. A date display is provided at the 6 o'clock position. The chronograph functions are controlled through two buttons, one (at 2 o'clock) for starting and stopping the chronograph, one (at 4 o'clock) for resetting the second and minute counters. The cam prevents the action of the reset while the chronograph is running.

    The 23 jewels are in the following positions:

    Balance staff bearings: 4
    Impulse jewel: 1
    Pallet pivot bearings: 2
    Pallet entry and exit jewels: 2
    Escape wheel pivot bearings: 2
    4th wheel pivot bearings: 2
    3rd wheel pivot bearings: 2
    2nd (or off set center) wheel pivot bearings: 2
    Chronograph second counter wheel, rear bearing: 1
    Chronograph minute counter wheel, rear bearing: 1
    Minute counter intermediate wheel pivot bearings: 2
    Coupling wheel pivot bearings: 2




    The Valjoux 7734 is a 17 jewel,cam controlled, chronograph lever movement operating at 18,000 bph. It has a running second dial at the 9 o'clock position, a 30 (or 45) minute counter sub-dial at 3 o'clock, and a sweep second counter mounted centrally along with the timekeeping minute and hour hands. A date display is provided at the 6 o'clock position. The chronograph functions are controlled through two buttons, one (at 2 o'clock) for starting and stopping the chronograph, one (at 4 o'clock) for resetting the second and minute counters. The cam prevents the action of the reset while the chronograph is running.

    The 17 jewels are in the following positions:

    Balance staff bearings: 4
    Impulse jewel: 1
    Pallet pivot bearings: 2
    Pallet entry and exit jewels: 2
    Escape wheel pivot bearings: 2
    4th wheel pivot bearings: 2
    3rd wheel pivot bearings: 1
    2nd (or off set center) wheel pivot bearings: 2
    Chronograph second counter wheel, rear bearing: 1




    Immediately, we see in first image of each pair the there is a significant difference in the calendar mechanisms. (NOTE- all images will have the 3133 first, unless otherwise noted.) Then both movements were completely disassembled, so each component could be examined and compared. I won't show the disassembly, as it would be rather picture intensive.

    Here are all the little bits and pieces.

    3133



    7734


    Let's look at the balance and balance cock first:








    We see that the 3133 uses a shim to control the end shake of the balance. This is typical from what I have seen in Russian made movements.

    Next the pallet and pallet cock:









    The 3133 bridge is shaped to accommodate the banking shoulders machined into the mainplate, the 7734 uses old-fashion banking pins.


    Continuing with the next piece to show a marked difference, the hammer:





    The significant thing here is the eccentric placed in between the legs of the 7734, this eccentric will change the relative position of the two hammer faces. This is done so both faces will be in contact with the cam hearts at the same time when the chronograph is reset. If one face was further back from a cam heart and not in contact that chronograph hand would have play and would not reset to zero reliably. This design was simplified in later versions of the 7734. The new design has a floating hammer face pivoted in the middle so it will self-level. This design is used in the 7750 series.

    Next, the brake:





    Minor differences in the manner of attaching the brake to the plate.

    Minute counter sliding gear:





    The one is jeweled and the other is not. But the major difference is in the 3133, this part is two halves held together by a small screw, in the 7734, this part is riveted together making it a permanent assembly.

    The bearing for the third wheel,





    This is the mainplate, note that the 3133 has a small bridge for the 3rd wheel. This is because the pivot for the 3rd wheel is inside the gear diameter for the 4th wheel. In the 7734, the 4th wheel gear goes under a cutout. Because the 4th wheel also has the long pinion for the running second hand, getting it out from under this projection is difficult, the gear actually must be bowed slightly (it springs back into shape.) By making this small projection removable, the 3133 is much easier to disassemble.

    These next two pictures are of the screw for the start/stop lever:





    The significance of the three cut across the head of a screw is that it indicates the screw is a left-handed screw. The 3133 uses left handed screws for three things, the start/stop lever retention/pivot, the reset lever retention and pivot and the minute counter sliding gear. All of these rotate in a counter-clockwise direction and would loosen a right-hand thread. The screws for these items in the 7734 are conventional right-hand threads.

    More to follow...
    "When a true genius appears in the world, you may know him by this sign,
    that the dunces are in confederacy against him."

    -- Jonathan Swift


    lysanderxiii Ming The Merciless
    Posts: 1785Joined: Thu Oct 12, 2006 3:20 amLocation: USA Top


    Re: Полёт 3133 versus Valjoux 7734 (with pictures, lots of them)

    by lysanderxiii on Mon Jan 12, 2009 4:33 am
    Now, I shall show you the reason a 3133 cannot be used as a direct replacement for the 7734:



    (3133 on the left) First the dials cannot interchange as the dial feet are not located in the same place. The holes for the dial feet are in the cutouts of the spacer ring.



    (3133 on the left) Next, we see that the 3133 is thicker, over a full millimeter thicker. Even when the calendar parts are removed from the 3133, it still has a bit more stem height than a 7733, so it just cannot be used in cases intended for Swiss movements.

    Now, just some comparison shots, maybe you can see the differences in quality.

    Minute counter wheel (Note - The 3133 cam hearts have grease on them, this why the surface looks uneven.):







    Chronograph second wheel (Note - The 3133 cam hearts have grease on them, this why the surface looks uneven.):









    As you could see in the very first set of pictures in this thread, the calendar mechanisms were quite different, but there is a fundamental difference that make all the parts non-interchangeable. See if you can spot the difference:



    In fact, the bridges all had different alignment pin locations, so none of the 7734 bridges would fit on the 3133. On the This makes me question the long assumed tale of the Russians buying old 7733 machinery and starting production. What this looks like to me is the bright boys over at the First Moscow Watch Factory got a hold of a few production 7733s and tore then down and made new drawings.

    Although the 7733 and 7734 have been through several modernizations during their production run, and I do not know how many of the improvements we see in the 3133 were incorporated in the 7733/7734. But it is the little things that were changed but had no technical reason to be changed that lead me to this conclusion.

    Now, I think I know the next question that you all are thinking, "How the quality/reliability of the 3133 stack up against the 7734?"

    Interesting question, in my opinion, the 3133 is a much easier movement to work on than its Swiss half-brother. The thickness of the gears ans cams is the same and the quality of the cam surfaces is very good (see below). Had the two movements been made in the same facility, with the same quality program, the reliability would be the same. Case in point, the old version of the PRS-5 with the 3133 movement, these were inspected prior to casing up, and have according to what we hear on the various watch fora, have performed well in service. (By inspecting prior to casing, we are retroactively applying a higher standard of quality assurance, not the most efficient way to do things but it does the job.)



    "When a true genius appears in the world, you may know him by this sign,
    that the dunces are in confederacy against him."

    -- Jonathan Swift
    Attached Images Attached Images





















































































    Last edited by michele; January 18th, 2009 at 09:39.

    On WUS since 2002 - Russian Watch Forum moderator from 2005 to 2012

  2. #2
    Member overakias's Avatar
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    Re: Poljot 3133 vs. Valjoux 7734 (by Lysanderxii)

    Excellent info!

    unfortunatly i cannot use a 7734 dial to my poljot 3133 movement i was thinking to change my plain white dial with some 7734 of the 70s with nice orange hands! there are available 7734 dials online but not much of 3133!

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