Caseback swap possible with new 3861 Speedy Pro?

ae86guy · Nov 12, 2023

Bumping this again. Wondering if anyone has successfully managed to install a genuine Omega 3861 sapphire caseback on their hesalite 3861. I've read they are swappable, but are there any complications with gaskets, movement ring etc?

I recently had to let go of my 3572.50 and wondering if it's possible to recreate this combo with the newer models.

Normally I'm against installing anything that's not original to the reference, but seeing as Omega is unlikely to ever offer this combo again, and I am hoping to use a genuine Omega caseback (not the aftermarket ones), IMO it's a justifiable "mod".

Unlike the previous generation which used 1863 vs 1861 on the sapphire models, the 3861 is the same for both, too. So you could argue the 3861 on the hesalite is "meant to be seen".

Not to mention, it is probably the most easily reversible mod you can do to the watch with minimal risk.

Which brings me to my next question - seeing as Omega no longer uses the wax seal, would it not be possible to simply reinstall the solid caseback in the event of a service/warranty work? Sorry if the answer to this question is not obvious.

GrouchoM · Nov 13, 2023

Prior to the 3861, the Speedys needed the backplate to ensure magnetic field protection. I'd doubt those earlier (non-Si) models would be sanctioned for EVA when a display back was used.

ae86guy · Nov 14, 2023

GrouchoM
Prior to the 3861, the Speedys needed the backplate to ensure magnetic field protection. I'd doubt those earlier (non-Si) models would be sanctioned for EVA when a display back was used.

Correct. The sapphire models were never qualified for space, whether sapphire on both sides or just the back like on the 3572.50. Personally, I like the idea of a 3572.50 or a modern equivalent solely because I like the look of hesalite but still want to enjoy the view of the movement. Could care less about it's flight readiness/qualification (or lack thereof).

chnzwh · Nov 15, 2023

FWIW I have a spiralwinder sapphire caseback installed on my Hesalite 3861 Speedy with no issue, it was also pressure tested to 5 bar at two different ADs, passed both times. The watch somehow felt thinner too.

Meme-Dweller · Nov 15, 2023

I managed to snag a genuine sapphire 3861 caseback from a seller on eBay in early 2022. Apparently very hard to come by as I have not seen another anywhere. Was going to buy a hesalite Speedy but then the issue with the 3861 bushing came out and I decided to wait. Now that time has passed, most new Speedies won't have this issue and as a bonus also come with the adjustable clasp. I'm just waiting for a good deal to pull the trigger then install this 😀

From the videos I've seen of people installing the Spiralwinder caseback on the hesalite model, it looks identical to the sapphire in that it is also set up to have 2 caseback gaskets. On the 1861 model, if you want to modify it with a genuine sapphire caseback, you would have to get a second gasket as well as replacing the movement ring (spacer?).

Foo2rama · Nov 15, 2023

PhilF
Well, based on the certification test protocol from "Moonwatch Only" I'd guess no.
I would think it would have to be in the original configuration, Hesalite with a solid back. I don't think the sapphire on either side would survive the test, although it seems that other watches with sapphire have been used in the space programs (Z-33 & variants), although the risk of a cabin in a weightless environment filled with floating shards of a sapphire crystal probably still exists. Perhaps I'm incorrect, but I believe the Speedmaster is still the only approved watch for EVA.

ESA approved a Fortis for Eva work.

ae86guy · Nov 16, 2023

Meme-Dweller
I managed to snag a genuine sapphire 3861 caseback from a seller on eBay in early 2022. Apparently very hard to come by as I have not seen another anywhere. Was going to buy a hesalite Speedy but then the issue with the 3861 bushing came out and I decided to wait. Now that time has passed, most new Speedies won't have this issue and as a bonus also come with the adjustable clasp. I'm just waiting for a good deal to pull the trigger then install this 😀

From the videos I've seen of people installing the Spiralwinder caseback on the hesalite model, it looks identical to the sapphire in that it is also set up to have 2 caseback gaskets. On the 1861 model, if you want to modify it with a genuine sapphire caseback, you would have to get a second gasket as well as replacing the movement ring (spacer?).

Great find! You'll have to post photos when you have it on your 3861! It's great that it is basically a 1:1 swap unlike on the 1861 with the movement ring etc. Did you happen to get a part no on the caseback when you bought it by any chance?

I'm not entirely opposed to the spiralwinder caseback/aftermarket mods for the most part. I have a number of modded Seikos with aftermarket parts. But something about a $100 caseback on a $7000+ watch just doesn't feel right. If I can get the genuine Omega part I'd happily a few extra bucks to keep it all-Omega.

Caseback swap possible with new 3861 Speedy Pro?

ae86guy

GrouchoM

ae86guy

chnzwh

Meme-Dweller

Foo2rama

ae86guy

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