How much drag are you putting on the feeler? I posted up a ticking thread around here somewhere that I'm finding to post the fix. I had the same exact thing happen. Then I took it to a Toy guru I know and he adjusted them and I felt how much drag he was putting on the feeler gauge and it was way more than I was. Now it doesn't tick.
I tried it a couple of different times. light, medium, and then a good amount of drag. I'm at the point where I just said screw it. I'll install a bigger amp, and turn the radio up.