I went to use my Necchi Lydia machine and the motor is making a terrible noise and the machine will not sew. Does it need cleaning, oiling or do I have a motor issue?

Sounds like it has seized due to lack of TLC, cleaning, and oiling. Continued use of the motor when the machine is frozen can burn out the motor.

I have a Necchi Logica (Kenmore Sensorsew) and it was making a grinding noise, I bought new brushes, bought a technical repair manual for my machine. But, it needed a new motor, so if it is making a grinding noise, it is because the motor seized up and broke the pulley for the belt. No one would fix it because it was too old, I bought it new in 1988. Well, I kept watching on ebay and found a used motor, that was the answer. If, that is your case and you really love your machine be patient and find a motor, but just be sure that you don't spend more than it is worth. Sometimes, those "old girls" can be had for a reasonable price for the whole machine. I see on ebay, a few for sale at around $100 but shipping is $50 some dollars. They are heavy, and they were made in Italy, so kind of nostalgia.