I had exactly the same problem. I tried using the supplied superuser.zip and also the zip file (actually, several versions) from SuperSU. In *every* case, root didn't work, and the superuser.apk which was deposited in /system/app seemed to not be recognised by the rom as an executable, and didn't show up in the app drawer. The zip files all checked out good: no corruption.
In the end, I installed SuperSU from Google Play, which worked perfectly (and I even successfully installed it as a system app, by choosing this option from within the app itself).
By the way, the vanilla rascarlo vanilla rom referenced in the OP works perfectly, with none of these problems.
Hopefully this helps someone else who is struggling with this!
Sent from my Nexus 4 using Tapatalk
Change the kernel and install the root. It was a error of stock kernel.