UPDATE!

3/8/2017: I added an updated version of the hotend_base file, called "hotend_base_v2." After struggling with some part corner lifting (more than I would have thought, even with ABS) I did some flow visualization and determined that a slight amount of air was blowing across the print bed and the printed part. This air was circulating around the underside of the carriage below the rear side of the heat sink fins. The new hotend_base file shrouds the rear of the heat sink, leaving a duct for the air to escape through the original stepper motor bore hole and onto the top side of the carriage, away from the print bed. While this is an improvement in restricting airflow, it didn't make things air tight (to my eye anyway), so I wrapped the underside (between the fan duct/base of the heat sink and the hot end heat block) in a little aluminum foil, secured with some electrical tape (far from the hot parts), to make sure no air was escaping and blowing onto the print bed. I've run the printer for about 15 hours so far on three medium-large solid infill parts and it seems to have reduced some of my curling problems, even for these challenging parts.

hotend_base_v2 is a drop-in swap for the original design, so if you're already running this Bowden conversion you should be able to print the new part in 20-30 minutes and swap it out pretty easily.

I will probably redesign this entire hot end assembly at some point and post it as a new thing. It has always bothered me that the fan duct isn't securely attached to the hotend base before installation, it makes removing and reinstalling this thing pretty fiddly, and I usually feel like I need three hands to do a good job. Aside from that I intend to design a layer cooling fan mount and duct that is easily removable with thumbscrews (so you can quickly remove that extra weight and bulk when not printing PLA). I'm hoping to be able to make one that doesn't have the belt passing through it (like another design does on Thingiverse), as I think that makes installation and removal a huge PITA. I'll also put more consideration into how I vent the hot end heat sink cooling airflow, probably leaving a larger exit hole through the original stepper motor bore hole and forcing it to blow straight up.

Original summary

This is an all original design for converting an XYZ da Vinci 1.0 to use an E3D V6 1.75mm hot end and a Bowden style extruder. It does not require any drilling, bending, or other permanent modification, except you may have to draw a 12V line from the power supply to drive the stock always-on E3D V6 fan that blows over the heat sink. You should be able to install this mod without removing the carriage, cutting up any plastic panels, or anything similarly inconvenient. Note that this mod will require you to run another firmware like Repetier, as it will require you to reverse the extrusion axis direction (easy to change in the Repetier configuration header file). The hardware side of the mod is completely reversible, although I don't personally know of a way to reflash the stock da Vinci firmware if you decided you wanted to go all the way back.

I designed this to be made of mostly small parts that are easier to print successfully on a marginal setup (like my da Vinci with the stock extruder and clog-prone hotend). The only real challenging part to print is the main extruder mount chassis, which has three areas requiring supports and a fairly long footprint that can be prone to lifting. Because a lot of these parts are under considerable compressive stress when assembled, I suggest printing this with a very high infill percentage. A sparse infill can lead to internal wall buckling that'll make the part fail. I printed mine as solid infill, as I do with any serious structural part.

This mod would technically work in a da Vinci 1.0a, but the 1.0a has holes drilled for a dual Bowden extruder mount on the top shelf of the chassis. You could do a more compact build by using the other Bowden extruder mount on Thingiverse (http://www.thingiverse.com/thing:846434). Despite the title that user posted, I believe his printer is actually a da Vinci 1.0A. Mine is a vanilla 1.0 and I do not have the holes for dual extruders drilled in the chassis, just a single center placed hole used as a cable mount in the stock design.

You may be interested in the E3D V6 hotend mount even if you're using a commercial Bowden extruder with another mounting method. Reusing the stock carriage without modification has several advantages. First, you won't have to attempt printing a gigantic carriage on an ailing da Vinci stock hotend. Secondly, the stock carriage is injection molded and has a far greater strength to weight ratio of anything you could ever print on your stock printer. Additionally, the envelope of the mount and stock carriage is such that you won't have problems with the carriage crashing into the Z axis rods or other obstacles in the build area. And finally, it's always nice to know you can go back to some degree if you change your mind. I can completely revert to the original hotend configuration in about 10 minutes with a few basic tools without even removing the carriage from the printer.

I see this design as pretty basic and straightforward, but I'm pretty happy with the results. Having the extruder output a little further forward lets me run a slightly shorter Bowden tube than I would otherwise, which generally improves print quality, all other things being equal. I'm currently running my infills at 80mm/s without issue, and I could probably go faster but the printer gets super loud, so I tend to run it on the slower side. I'm glad to not hear my printer sound like it's shaking itself to death doing infills on narrow regions, slinging that stepper motor around is a serious problem in cases like that.

As usual, use this design at your own risk, I am not responsible for any damages or injuries that may result from using these parts.