I have manged to solve the problem, the crank arm was not perfectly square so it could move in only one direction so even when tight it could move when large pressure on it so i filed down the oposite sides until it could move evenly in all directions and put it back together and it seems to be working so far, this was all because the bolt on the BB was not tight and the alluminum was diformed. Thought id post this if anyone is havin the same problem.