help with bit char-g?

[mini1ks]

Hi iam new to this bit char-g thing i just bought the project D set that came with a b1.0 motor and then i bought a 3.0 z-car motor pack and swap the motor in it ran for a while until i dropped it the motor doesnt run anymore i put back the stock 1.0 motor it works runs and i went out to buy a 3.0 z-car motor again it doesnt work any clue i have tested the new motor with some batteries and it runs i was thinking if its the original nicd battery that sucks planning to upgrade to a nimh 100mah? or should i just go with bit-charg motors or microsizers because i heard the z-cars suck any help? thanks