Timing chain problem?

[rps13det]

my 240 is starting to have a loud *** "clack" "clack" "clack" sound under the valve cover. I asked a friend and he told me that it might be that I need to replace the timing chain. from what i know, it sounds like a whole day job. does nissan sell a timing chain rebuilt kit, or are the parts sold seperately? if anyone has done a timing chain job please notify me. thanx. any reasonable help would be appreciated thanx.

[JNM240]

There is a sticky at the top of this forum. LOTS of good info there.