I discovered yesterday that the pulley end of an XU10J4R/RS cam is identical to an XU5/XU9 cam. So this means you could fit a GTi6 adjustable pulley to a 205 cam. After some accurate measuring, this is how to do it:
width - the GTi6 pulley is 31mm wide, the 205 pulley is 22mm wide. So you need to face 9mm off the inside.
offset - there is a slight difference of 2mm in offset. ie the distance from the end of the cam to the outside of the pulley - 16.5mm for 205 and 14.5mm for GTi6. Ideally you should add a 2mm shim between the GTi6 pulley and 205 cam. However, the 205 cam belt is 17mm wide running on a 22mm wide pulley. Thus a difference of 5mm. Depending where exactly the belt runs on the pulley will determine if you need a shim.
I have spare GTi6 pulleys if anyone would like to be a guinea pig!
width - the GTi6 pulley is 31mm wide, the 205 pulley is 22mm wide. So you need to face 9mm off the inside.
offset - there is a slight difference of 2mm in offset. ie the distance from the end of the cam to the outside of the pulley - 16.5mm for 205 and 14.5mm for GTi6. Ideally you should add a 2mm shim between the GTi6 pulley and 205 cam. However, the 205 cam belt is 17mm wide running on a 22mm wide pulley. Thus a difference of 5mm. Depending where exactly the belt runs on the pulley will determine if you need a shim.
I have spare GTi6 pulleys if anyone would like to be a guinea pig!