First thing.. please link all your other relevant threads. They are important to the diagnosis and when possible should all be kept in teh same thread to make it easier to follow the issue.

On one thought, I'd say rod bearing, but a cold start is usually more quiet and less perfect in the exact speed of how it hits. Like some have said, it's possibly flex or balancer. Maybe even the balancer out of position. Did you sit the balancer on the keyway solidly before you hit it etc?