Free epic chest

At what point does the free chest legendry switch to epic chests? 

If failed to find the info on the wiki.

you means the inverse. When the epic switch to legendary. Level 61

the legendary is random. Sometime you get between 800k and 1M gold or more. Sometime you got crap a little gold,items and pearls.

the hour seem to depend of your country. Some get them each 2 hours,others each 4 hours and I have hear some get them each 6 hours

You must look in Daily Rewards :

Wow, I need new spectacles… or perhaps I am tired. Thanks.