If your feeding the Bump output, you may possibly not see any effect for either of the follwoing reasons :-

1. The range required by the output is always -1 to 1 and may be clipped internally.
2. As bumps only generate the appearence of the surface being moved, you may just not see the the effect your expecting if it's too strong.

One thing you could try is to use a terrain and control the height (the only way of getting real displacement in V5I).
There was a script called (something like) "Box of Rain" which might help with this.

Using the "Function Node Preview" window will help you to see what's going on at each stage in a series of nodes.