Your workouts last 4 hours?
Anyway, protein can be absorbed just as well before a workout as after. Try to keep it within 30 minutes of the start of your workout. Eating afterward should include protein and carbs. If you eat your dinner after the workout then it shouldn't be a problem to halt muscle breakdown and begin rebuilding the muscle.
If you are worried about eating a heavy meal late at night, eat larger meals in the morning and taper down to the final meal after your workout. Eat every 2-3 hours, each meal with a protein source, etc. John Berardi's site has detailed info on how to plan your meals for all different goals (fat loss, weight gain, etc.)