I have a 2000 Honda Accord SE with a SOHC 2.3L 4-cyl VTEC engine (F23A1). With the hood up it is pretty loud. I adjusted the valves but came away not really comfortable with a lot of what and why I did things. First, I understand how VTEC works. What I am struggling with is understanding the importance of valve clearance and why too tight is much worse than too loose (or is it?). My engine is an interference engine. In my engine the valve clearance is adjusted just above the valve stem, so I think I understand that too loose means that the valve would stay open too long and the piston might or would hit it, and that would be very bad. What goes wrong if it is too tight? It forces the rocker arm against the camshaft too much and scores the camshaft? Or it drags too much on the camshaft and overheats or? And why is adjusting such a touchy-feely pain in the xss? Is there any reasonable rule of thumb for setting the valve clearance given that the feeler gauges come in discreet sizes? Like pick the one that is nearest the center of the spec for clearance and then tighten until the feeler gauge won't move without significant force, and then loosen by 1/8 of a turn? or? Can a reasonable judgement be made from just listening to the engine whether the net effect of adjusting the valves made them effectively too loose or too tight or just right? It leaves me wishing I only had Goldilocks problems. IMHO Adjusting valve clearance would make a good YouTube video if any sense at all can be made of it across engines and manufacturers.