Timing chain/guide or valve?

[Florida240sx]

93 240sx DOHC 178k Changed oil about 2000miles ago if not less.Today I got seafoam to run through my brake booster.When I popped my hood I heard this ticking from the valve cover.Pretty loud. It seems to be above the 1st cylinder...I'm going turbo in 3 weeks.Car does not burn oil.Any ideas on what it is?Thinking chain or chain guides or valve.But seem like sound is over 1st piston.Should I add seafoam to my oil and then come back if problem still exist?Thanx AIM: florida240sx

[navysnail]

make sure its not an injector, then listen with a mechanic's stethiscope if you have one, otherwise you can use a long extention and put it up to your ear to try to pinpoint the location of the noise

[Florida240sx]

It's the timing chain/guides seems to be chain though.All right this ain't going to be fun.Where's a thread that shows me how to do this.And I don't need the guides do I?