take a look around under the hood, possibly some burning rtv silicon if u used it for the gasket material, a hose that is somewhere it shouldnt be, could be a lot of things, and most often its something unrelated that is just touching something hot, check out ur radiator fins for any signs of duct tape, ur exhaust manifold and intake manifold, check all ur vacume hoses, make sure everything is as it should be, also check the seal of ur valve cover clean everything off with some type of cleaner and check for oil leaks.