What is causing so much build up on my /6 valves ?

That does make sense. I guess that can also explain the burning of oil. I usually have to put a new quart of oil in every two months. But it's every single intake port. I guess the wrong guides were used huh for those ?

Just a side thought, would I be able to tell if they are loose if I could reach in with some needle nose pliers and see if it has play in its movement ?