Sam, Is your Z-120 making more noise than it used too? These old mechanical overhead cam engines make more valve noise than "modern" hydraulically driven valves. Thought my TO-20 had noisy valves when I bought it. An old timer told me the same thing. (does that mean I'm an old timer now?) I rebuilt my engine top to bottom, tore my valve train totally down, inspected, cleaned, etc., wouldn't you know...still makes the same noise. I've run the engine with the valve cover off, didn't make a big mess. Not a lot of oil there, just enough to keep everything wet. If you are really worried about it, or it is worse than it used to be, it is an easy job to pull the whole rocker assembly, take it apart, clean/inspect, put it back on, and re-check your tappet clearance. I agree with 'ol Mr. Chapp about making sure your valve stems & valve stem caps(if you have them) are good and square, but I would be too scared to tighten down those valve clearances for fear of losing compression or burning a valve. If the stems and rockers look good, I'd say set the factory cold gap and enjoy the sound of a vintage Ferguson clacking down the road.
|