Exactly, the e3d is not compatible with ,my extruders because the aluminum barel has a huge diameter , it's a very big hotend, will post tomorrow pictures of the different hotend types I have.
It will fit inside but it is not stable, the dimension of the e3d is not really same as the j-head. I try today to see if i can do a kind of adapter but i cannot, sorry. I have meassured the e3d holder and posted here the picture,you can compare and know what i mean.