[Shak2k10]

I've had misfire problems for a while so I've checked everything an found my problem, retainer spring had been snapped on the valve train... Got that changed and now the car doesn't miss a beat

BUT

The car still has a rhythmic tapping noise that you can hear clearly and as you put your ear more closer to the engine theres a large knocking/tapping kinda sound, I've been told it could be a piston but I just wanted some other ideas on what it could be and if it's a major problem or nothing to worry about or if anyone has had problems like this

I would really appreciate the help

Thanks