Tezzeret, Cruel Captain

The emblem’s triggered ability doesn’t remove any abilities, types, subtypes, or supertypes the artifact has.

If the emblem’s ability causes a Vehicle to become an artifact creature, its base power and toughness will be set to 0/0. Crewing that Vehicle will not restore its power and toughness. Similarly, if the ability causes a permanent with station to become an artifact creature, putting an amount of charge counters on it greater than or equal to the amount required for it to become an artifact creature won’t overwrite the base power and toughness set by the emblem’s ability.

If the emblem’s ability causes a Vehicle to become an artifact creature, it doesn’t count as “crewing” that Vehicle for any ability that would trigger due to a Vehicle becoming crewed.

If a card in your library has {X} in its mana cost, X is 0 for the purpose of determining its mana value.

The resulting artifact creature will be able to attack if it’s been under your control continuously since the turn began. That is, it doesn’t matter how long it’s been a creature, just how long it’s been on the battlefield.