Well I didn't know the tensioner pulley bolt was reverse thread and I broke it. I was going the opposite way on it with a pry bar and it snapped. Lol. Live and learn.

 

Looks (sounds) like I have the same problem. Changed the oil 1 week ago and immediately started hearing this knocking. I have an '04 with 42K miles on it. I'm planning to start with the TCT then the serpentine belt pulley, but before I started I wanted to ask if anyone found any other causes or fixes for this. Thanks for sharing.

 

Well I changed the tensioner bearing and the noise is a little better but still there. I still have to change the other bearing on the lower pulley but I don't think that's the problem. I'm just hoping it's not coming from the block. Take off belt and run it for like 20 seconds and see if u hear it.

 

If it goes away when removing the belt, but didn't when you replace the bearing it is the tensioner itself.

 

You mean it might be the entire tensioner piece. Because I just replaced the tensioner pulley. And my next step is the lower pulley with the smooth surface. Both tensioner pulley and other pulley had play. So I'm hoping that was the problem.

 

That noise is so common, all of my S2Ks did it. Weather it was AP1 or AP2. Your noise is just much louder. The noise is still present when removing coil pack from either cylinder 1 & 2, I can hear it. I've posted video's and never got answers.. people just said these engines sound like their is rocks in it (O_o) go on a few vids on YouTube and listen to theirs idle. Avoid the stupid TCT noise videos.. find a video that is just stock idle, you'll hear that same knocking noise. I'll try posting some

https://www.youtube.com/watch?v=8DoiFdVEqyk#t=76
(Specifically at 1:16 mark, that's the same knocking, just a bit quieter)

https://www.youtube.com/watch?v=FGrPjfhppMQ

 

The second video sounds like mine. But I don't think it's normal. I have a friend that also has an s2000 and his doesn't make that noise.

 

Yes, the entire tensioner sometimes fails.

 

dam I knew I should of just bought the whole thing.

 

I'm pretty sure my '05 has had it since I got it at 28k miles. Not as loud as yours at 60k , but my gut feeling is its normal. Your car runs OK right--just the noise?
I'd take it to a competent Honda mechanic before diving into any repairs.