I had the similiar experience after an engine rebuild. My issue was the lifters. You might be able to locate my videos in the technical forum by searching my user name. From help from fellow TT.net fmembers I used a stethescope to isolate the noise to the lifters. I documented the lifters that were suspect and inspected them once they were removed. The louder ticking noise was from the lifters that were basically seized which caused clearance between the lifter and valves stems. I tried all types of snake oils (Marvel Mystery Oil, zince additives, Lucas treatments, etc) and nothing worked until I replaced all the lifters and now there is no issues. You can also use the stethescope to investigate VTC noise, timing belt noise, etc. Good luck!
