Steering Rack problem ?
 

When my car ( 1970 911 T ) is stationary and I turn the steering wheel the wheels don't move and there is a loud grating- like noise. What's up and how to I fix it ?

I would guess one of two things: either your rack is on it’s last leg or one of your U-joints in the steering system is loose. Hopefully it’s #2.

You can open the smugglers box and check for rotation there. Try turning the wheel and see if the U-joints are tuning easily or if the noise is coming from them. If they are tight and turning as you turn the wheel with no noise, the issue is probably in the rack.