Why does your 3 liter engine tick when cold?

Any engine can tick or have a slight knock or ping to it when it is cold. It's pretty normal. As an engine warms up the metal expands. Most of the time it's the valves/valvetrain. Some times it could be a bit of piston slap. Basically, as the valves expand when the engine gets up to temperature, the slack is taken out of it. I would suggest letting your car warm up before you drive off. Running a cold engine hard can lead to excessive wear.