could be the start of a failed rod bearing...ive been there that aint good...when you say ping...be more specific...does it sound like metal on metal or what? if it is a failed rod bearing it shouldnt take long before you can actually feel the "knock" if you put your hand on the motor..pray its nothing that serious..im guessing its your 98 ex civic....what the mileage on it? have you changed the timing belt? have you had a valve train adjustment? it could simply be a rocker