file location:

/usr/share/pyshared/openerp/addons/web_calendar/static/src/js/calendar.js

Code:

slow_create: function(event_id, event_obj) { var self = this; if (this.current_mode() === 'month') { event_obj['start_date'].addHours(8); if (event_obj._length === 1) { event_obj['end_date'] = new Date(event_obj['start_date']); event_obj['end_date'].addHours(1); } else { event_obj['end_date'].addHours(-4); } } [....]

I change:

event_obj['start_date'].addHours(8)

With:

event_obj['start_date'].addHours(7)

Now the default value is 7AM