I am using the crank that was on the bike, a Dawes Civic. I am running singlespeed with a shimano bmx freewheel and a kmc 510z chain. Its an unusual noise that i get, it comes and goes. I was suspecting the freewheel.
I will post more details up starting my own thread when I can.
Check here https://www.lfgss.com/thread17258.html