[sierrap615]

the lifter was hitting the valve cover? i don't think thats possible. the rocker arm is in the way, and for the rocker arm to hit the valve cover the valve cover would basicly need to be dented in. a rapid ticking noise is commonly caused excessive lifter to rocker arm clearance, causing the lifter to hit the rocker arm every time the camshaft spins instead of it staying in a constant contact. the lifter is automaticly adjusting via oil (hydrualic) pressure which will make the lifter want to expand to fill that gap between the rocket and lifter. if the lifter is not supplyed with enought oil pressure, it not be able to expand or "pump up". this tick is also more common with the engine cold, as the oil is to thin to fully pump up the lifters. so what to do:
1. change your oil and filter - dirty oil will restrict oil flow to the lifters
2. use the proper 5W-30 or 10W-30 - other viscostys have different thicknesses and therefore different flow and pressures attributes.
3. maintain you engine - namely, such as in the case of the old engine out of my '94, worn timing chain guides resulting in debris thru out the engine and oiling system.

i have a feeling thats more info then you were expecting...