Rotor rubbing cap

I was changing my oil and adjusting the valves today. When I took the distributor cap off of the distributor, I notice a fine orange powder inside the cap. After inspecting the cap much closer it turns out that the rotor has been rubbing the inside of the cap and creating this fine plastic dust. I am wondering about the health of my distributor and what would cause this rubbing of the rotor. The point at which the rotor is rubbing is where there is the molding for the snap clip protrudes inside the cap. The indented area on the outside of the cap is protruding inside the cap.
This has not happened previously to me and this car. Is there a way to check to see if the distributor is the cause or if the rotor is the casue. All the parts are from local Porsche supply shops. The car is a 1972 911 T Targa 2.4 MFI w/ Bosch distributor and 6500 RPM rev limitor rotor.

Those bow springs that hold the cap on have to be exerting equal tension on either side of the cap to keep it seated. I had the same problem years ago. The solution is to bend the clamps so that they both have the same curve and effectively snap into place when bowed inward.
One of the two on yours may have flattened out and allows the other side to pull the cap off its seat.
Make sure that the cap is not reversed by 180 degrees. That would keep the key on the cap and the notch in the distributor from mating.

Thanks,
the springs seem to not very much tension-nothing like my 356. I'll have to check and make sure that I did not install the cap 180 degree out of phase. Is it possible that the spring steel that is inside the rotor cap is bad or in the correct configuration. I'll try an old rotor to see if this condition continues.
pd
72 911T

I have a 72 911E. I think it is virtually impossible to install the distributor cap 180 degrees off. It is very easy as pointed out by the previous poster to not get the cap seated properly, leaving it at an angle. However, I think this would not allow the car to run right. I would try the old cap and rotor first, then pop in the new rotor with the old cap and see if that is the problem.

Kurt V
72 911E

after switching to a breakerless ignition my rotor was too tall for the cap and rubbed slightly like yours. my solution was to file off a mm or so from its base.

after switching to a breakerless ignition my rotor was too tall for the cap and rubbed slightly like yours. my solution was to file off a mm or so from its base.