Do you mean a reload, a restart of a particular service, or a restart of all the services? Assuming you want to restart all services at 4am, you could add a file to the /etc/cron.daily directory with these contents:
!/bin/bash
/usr/bin/bigstart restart
If you want to restart a specific service, like tmm, you could use these contents instead:
!/bin/bash
/usr/bin/bigstart restart tmm
Finally, if you want a different time, you can edit /etc/crontab to change the cron.daily time (careful here, there are other processes that also kick off with cron.daily, so make sure this is what you want) or you can create a file in another directory independent of the /etc/cron.* directories and add an entry to /etc/crontab at the time of your choosing.
Google cron & crontab for more details.