G'day guys,

On the weekend I installed a CA16 camshaft in my CA18. I went to start it and it started but sounded like a tractor. I let it run for a little while and it got quieter but it sounds like the front two lifters are not expanding properly. I have run the car 3 or 4 times since for a total running time of probably 45mins. The noise has, if anything, got worse. I have pulled the cam cover off a couple of times because I was almost certain there had to be damage to something but it all looks healthy. Has anybody had any experience with a problem like this?

I know that lifters wear out but they were fine before I changed cams.