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Rotor Swap Question

Posted: Sun May 14, 2023 11:25 am
by Cmiertschin
Hey all, my 3BF's valve casing has been messed up at some point in prior ownership, and my tech has recommended replacement when possible. It's functionally usable right now, just a little janky. I'm considering swapping in an Instrument Innovations rotor (and probably messing with the wrap to account for different sizes of parts); other option of course is finding a donor bell section and swapping rotors out. My horn has the two vertical ports (late 60's and quite "well-loved"), so adjustments would need to be made with a new 3BF rotor anyway. Thoughts on the I.I. swap? Or other possible alternatives? This horn is quite well-used, only reason I'm considering going a little wild with it.

Re: Rotor Swap Question

Posted: Sun May 14, 2023 11:32 am
by Burgerbob
I don't think Olsen makes a rotor in .530. The .562 large tenor rotor would be much, much too large for that application.

Re: Rotor Swap Question

Posted: Sun May 14, 2023 12:30 pm
by Matt K
I think the smallest after market valve I’ve seen in that size is Voight. Hagmann also sell a 530 but is obviously not even close to drop replacement

Re: Rotor Swap Question

Posted: Sun May 14, 2023 2:29 pm
by JohnL
Your best bet would be to find a donor horn. Obviously a 3BF valve would be the preferred option, but one from a small-bore Olds with an f-attachment might also work (they're .515" and have the same general port configuration as the early 3BF rotors).

Re: Rotor Swap Question

Posted: Sun May 14, 2023 3:15 pm
by MrHCinDE
You might have luck in finding one on here from someone who decides to convert their 3B/F to a straight 3B? Every so often that idea comes up. It‘s worth a WTB/ISO post in the classifieds at least.

Re: Rotor Swap Question

Posted: Sun May 14, 2023 7:31 pm
by Cmiertschin
Thanks for the thoughts everyone, I'll probably look for a donor horn or valve section.

Re: Rotor Swap Question

Posted: Sun May 14, 2023 8:49 pm
by harrisonreed
Screenshot_20230515-114843.png

Re: Rotor Swap Question

Posted: Sun May 14, 2023 9:15 pm
by JohnL
Cmiertschin wrote: Sun May 14, 2023 11:25 amMy horn has the two vertical ports...
So the OP's 3BF has the original valve layout, like this:
3bf.jpeg
as opposed to the new valve design, like this:
3bf-new.jpeg
so a using the new style valve wouldn't be just a drop-in.

Re: Rotor Swap Question

Posted: Sun May 14, 2023 9:29 pm
by harrisonreed
What's the bore size on the 36H valve? Would that work?

Re: Rotor Swap Question

Posted: Sun May 14, 2023 11:49 pm
by IdoMeshulam
I think I have what you need, bought it for a project but ended up not using it. Shoot me an email if you're interested.