The length of time for barbecuing pork loin depends on the weight of the meat. An internal temperature of 135 to 140 degrees Fahrenheit is required for pork, as stated by BettyCrocker.com. This averages to 20 to 30 minutes at a medium-high heat setting on an outdoor grill.
Contrary to popular belief, pork is safe to eat when it is slightly pink in the center, as long as the internal temperature is a minimum of 135 degrees Fahrenheit. To check the internal temperature, use a meat thermometer and insert it into the center of the meat. Use a central point in terms of both the length and width of the meat, as this is the last part of the meat to cook through.