I think you are using an "All-day" event rather than a timed event. Based on my testing it seems that the iCal print UI truncates lengthy text for All day events but not for timed events (event 1 is all day whereas event 2 is a timed event):
I also can't find a way to change this behavior.
I'd suggest you submit feedback to Apple to let them know you'd like the ability to print all day events with their text in it's entirety: http://www.apple.com/feedback/ical.html
As a work around, try changing your even from an all day event to a timed event (double-click it and uncheck the all day box).
Hope that helps!
In my experience it truncates in either "All day" or for timed events.
This is a annoying as printing looks all over the place especially when the schedule looks busy.
My workaround was to select View> List and add a weeks worth of days next to Ends:
This does result in a list format but it is more eligible.