help

[Kure91]

I have this rattling and I don't know what it is. Its coming from the area around the exhaust manifold. Every time the car reaches around 3k-3500 rpm it starts. My neighbor said it sounds like my valves are rattling and said I should put some octane booster in it and that should help. I did that and i still hear the rattling. I also checked to see if anything looked loose and nothing appears to be loose. The car is a 1990 Nissan 240sx, and help will be greatly appreciated. Thanks in advance.

[justy90240sx]

remove your valve cover and inspect you timing set. its a common problem with the ka24e