I have followed your journey with much interest and impressed that you figured it out! Congrats!Another update: -
After much messing about I found one of the rocker arms was slightly loose, but not loose enough to remove. I pushed down on the valve spring and I was able to get the rocker arm and lifter out. The lifter is sticky/not moving/collapsed. I bought a new lifter and rocker arm. I had to loosen the camshaft bolts to install the new lifter and rocker arm. My book says that the camshaft bearing bolts should be tightened to 10NM which is not very tight, hopefully it is correct.
Once installed I turned the engine by hand and the new lifter/rocker arm and cam lobe aren’t getting as much oil as the other lifters/rocker arms and cam lobes, is that because the hole in the new lifter is smaller or is that the issue that caused the old lifter to bad? I took it apart again and blasted the hole where the lifter sits with 90psi compressed air to try to open up/dislodge anything that might be causing the low flow. I tightened it all down and turned the engine by hand again and I think its now oiling at about the same rate as the others. I cleaned the valve cover, put new gaskets on and tightened it all down to 10NM and took the car for a run. I sounds good the ticking has gone (hopefully for good).
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