Joint oscillating endlessly, zero damper

Is that even possible to make a game object with a joint oscillate endlessly, only with its damping set to zero (and some non-zero stiffness or course), without the use of drive/forces?
Whenever I do it, there seems to be a small damping nevertheless, and the game object comes to rest.
I just want to simulate an undamped mass-spring system, but it does not work at all, unless I set forces etc.
Sorry if it sounds like a dumb question, but I really got stuck in it. Just wanna make sure if the physics engine can perform that before moving on to another solution. Thanks a bunch.