Is it possible to have phase shift with only passive (resistor, cap, inductor) components?
Any combination of resistor (R) with inductor (L), R with capacitor (C), LC, or RLC can make a phase shift.
If the amplitude drop is not a concern, for all these circuits, the answer is 'YES'. But if you need the same amplitude and don't want to use any active circuits, you need to eliminate the resistor.
You will be left with an LC or CL circuit. I recommend the LC circuit. The L must be in series and the C in parallel to your output.
Again, if you're not using any active component, notice that any current drain from C will result in different phase shifts.
If you consider an open circuit like this:

the shift (delay) will be like this:

Read more in this PDF: Delay Lines.