Keney,
I ve done one feature film with eclair ACL and believe me it was a really painfull experience.
There have been many mods done to this cameras and some of them were from Eclair.
I want you to describe me how the take up side looks like, or post a photo of it, so I will know wht type of magazines you are using, the old ones or the newest ones.
The older ones have a weird mechanism with a rubber sprocket inside the take up side that attaches to the exposed! film and winds it up. This has to be about 5mm thick and not aged, if less than that then u will have a jam at about 30 meters of film.
About the loop, too big will make the film ''scratch'' itself in the magazine sides, I believe the best loop side (that Eclair recomends) is 12 -14 frames, for 200' mags and a minimum of 14 frames outside the magazine for 400' mags.
No problem if you easy the load with 200' on a 400', if u have a new magazine,wich I suppose you don't, (none of us have!), but If I don't have any description of the magazine then I can't be more specific.
I have repaired both of the ones I was using with some new sprockets that I ve found in a video repair shop! that worked excellent.
No jams no chips.
Also the heavy duty motor, most of the times has to do with the currency u are providing to it, u definately want new fresh batteries or more amperage batteries that can handle the load too.
Regards
Dimitrios Koukas