Hello Group. I've recently purchased an '84 civic w/ 12valve 1.3L engine. I'm hearing a noise in the top end of the engine which sounds to me like the rocker arms banging on the valves, due to too much clearance. I popped the valve cover off to inspect, and found all sorts of black carbonish buildup. I'm wondering what kind of problems I might have if I go ahead and adjust the clearances and end up knocking a bunch of the crud loose. I though about perhaps using compressed air and a plastic bristle brush to blow it all out of there... Your thoughts? Oh, and I'm pretty sure that this has NEVER been done on this engine, and is probably in dire need of being done Thanks!