How long will a motor last while needing a motor mount?

Motormounts (engine mounts) are used to connect a car engine to the car frame. Theyare usually made of rubber and metal. The metal portion connects to the engineon one side and to the frame on the other. The rubber is in-between to providesome flexibility (so engine shake doesn't cause the car to shake). Newer carsmay use slightly different mounts, however, there purpose is the same. Providethe connection from the engine to the car frame. The number of motor mountsvaries from car to car. Hope this helps.

your motor will be fine. it's other things you need to worry about. the motor will be able to shift around on acceleration and deceleration which can break things such as evaporative lines or even the power steering resorvoir. basically if your engine mount is broken, the engine is being held in place by everything attached to it and the body/frame. that's not ideal