I have a kit built Ender 3, which started out life as a voxel but was upgraded using an official Creality kit.
I don’t know the exact details as I’m the second or third owner.
I need a new x axis belt for the gantry arm, the one that moves the hot end from left to right.
What should I be looking for, and do the belts vary dramatically between ender 3 versions?
The existing one is wearing out but not yet broken and I don’t want to cut it off.
I don’t have an exact answer, but maybe this is enough anyway?
Belts sold as “GT2” or “2GT” with fiberglass core are almost universal across 3d printers. These belts have 2mm pitch between teeth. For this application, 6mm width is normal.
However, I see that Ender 3 replacement belts sold online have ferrules crimped to the ends, as well as discussion implying that the belts are connected by clamping to those ferrules. I don’t know first hand whether this is an important design element for the Ender 3. I’ve helped repair one or two Ender 3s owned by others but didn’t pay attention to how the belts were attached.
I have bought bulk lengths of GT2 belt and cut them to length, but I always used different clamping systems that didn’t require ferrules. There are 3d-printed ends available like Secure GT2 Belt End Clip by junaling - Thingiverse if you have another 3d printer available and want to try.
Anyone here with lots of direct experience with all the ender 3 variants please feel free to chime in! 
I’ve seen the belts with the crimps, but every printer that I’ve ever owned shipped with an endless belt.
I suspect that the frame was originally for a voxelab aquila before being upgraded with a creality ender 3 extruder and main board.
I’m very curious what printers you have owned that used endless belt to move the head back and forth. I’ve never seen that. Not saying you are wrong or that it’s impossible design, just that it’s outside my limited experience.
Similarly, I’ve never seen a bed-flinger use an endless belt for moving the bed back and forth. The main use of endless belts I’ve seen on printers is to couple motors to Z screws.
In your shoes, I’d be inclined to pick up bulk belt and cut to fit, rather than hoping that the conversion happens to be the right length for an existing belt, endless or otherwise. If that head is actually set up for mating to an endless belt, you can make any length loop you want, and you could put the splice at the print head so it doesn’t have to bend, which would let you use cheap CA glue for the splice.
every ender 5 I’ve owned had endless belts, and Creality actually sells endless belts through aliexpress.
https://a.aliexpress.com/_Eu2ARCi
maybe the difference is regional?
Those aren’t for the Z screws? Anyway, I would think you are limited by the design of the head on the unit you have; is it set up for crimped ends or loops? Pictures?
it has a loop on it, I’m not near it now so I can’t take a picture.
odd, but not with an argument, if I can buy it by the meter and crimp it, I can keep trying till I get it right.
Yeah, I have two ender 3’s. Is the axis the same demension as a stock Ender 3? and are you using the same extruder mount as..?
I believe an electrical ground ferrel would work, or a #10 crimp-on lug with the end cut off would work as well..