Tap Tap Tap!!! What is that noise?

[707kevin]

Sorry, send before I was finished.

Sounds like the right of the engine, #1 is exactly where you would hear the plastic pulley making noise. The metal hub will begin to rotate a few degrees back and forth and the plastic pulley wheel will have visible (small, but visible) cracks in it if you clean it up and check.

[blurple124]

I've just replaced the water pump (that had a wobble as well and was leaking) but the noise persisted. There was a slight rock in the plastic intake cam wheel. While the engine was running, I put a dowel rod to different points on the engine and identified the noise coming from the front of the intake cam/cylinder 1 cam lobe. Given the feedback here, I've ordered replacement cam wheels and will report on the progress of those changes!