Is there any background available for Karak Izor?
Is it mentioned or detailed in any adventure or such (also 2nd Ed.)?
I plan on converting Black Fire Pass's Karak Azkaraz to Karak Izor (basically pretend Karak Azkaraz does not exist and is Karak Izor instead)and would hate it if I would stumble upon something on Karak Izor later and have to change everything again.
Do the lore-experts see any problem in this?
For Dwarf-lore the best sourcebook to start is the Dwarfs: Stone and Steel (WFRP1). On page 36 the book has some (maybe 1/3rd of page) info about the hold.
I dont think there is any problem to change the Karak Azkaraz to Karak Izor. Yes - They are very different types of holds (izor old and large, azkaraz small and younger), but why wouldn't it work…
Here's part from the description:
"Karak Izor ("Copper Mountain") is the first and largest Dwarfhold to be established outside the World's Edge Mountains. Its age and prestige are such that Dwarf settlements across the Vaults, and as far afield as the eastern Irrana and northern Apuccini Mountains, look to Karak Izor for protection and guidance. The hold is ruled by King Kazran Grimbrow and Queen Astrid the Wise of the Izorgrung clan."
Ah, thanks a lot! Will try to get my hands on this book!
Technically it can be done. Also look at page 9 of Stone & Steel. There it is stated that the King of Karak Izor is trying to bring the Karaks of the West into one Karaz Ankor opossing the world Edge Mountains. He is even trying to build a new system of tunnels to connect the western holds like the great underway in the World Edge Mountains. All this could lead to civil war though.
Also you might have a look at the second book of the Doomstone Capaign, "Dwarf Wars" there two different Dwarven groups try to find an artifact in the vaults. One is a western group, not mentioned but Karak Izor is the nearest, the other group is an expedition from the southern worlds edge mountains.
If you want to have some more ackground on a dwarven hold try thsi by the dwarven master himself, a complete sourcebook of Karak Hirn.