We instaled a hmt kit on my friend's 92 civic with a d16 vtec this weekend and everything was fine until today. There is a small knocking sound coming from the valve cover at idle and gets louder and faster when he takes of in 1st gear. I think something is messed up in the head like a valve, retainer or spring. No smoke or idling problems or lean problems at all. What is it?

 

maybe valves need adjustment?