I have the infamous chain rattle off the top chain guard. after reading a few posts, i found that the top chain guard is pretty useless, and that nissan actually stopped putting them on. My friend wanted to see where exactly the chain was hitting the guard, so i went in and turned it over (spark plugs removed of course), as i was turning it over he kept telling me to keep going. finally i got out and asked him what he was watching, he said watch the exhaust cam, he went in and turned the key, and the exhaust cam gear actually "wiggles", either the cam gear is bent, or the end of the JWT cam is bent. anyway i took the guard off, no more noise. I'm really really sure that we did the install right of the JWT s4's to begin with, so why would that cam gear be wiggling, i even cranked on cam bolt to make sure it was tight, and it was. Do you think that exhaust cam left JWT already bent? and if it did, would they honor a replacement? hmm i don't know. what do you guys think?