This is my first post, I hope this hasn’t been gone over before! I am wondering on the effect of Molybdenum Disulfide or Titanium Disulfide on the brass present in motors. I have been reading a bit on GL 4 and GL 5 gear oils and the difference in sulphur levels affecting gear boxes with brass components. Is this the same problem with engines, or does frequency or oil change, etc, make a difference. Thanks in advance.