My 7 speed straight block Regina is starting to exhibit strange symptoms. When I put it on a rack and let it freewheel (spin the rear wheel foward) I sometimes get a sound like loose marbles. I assume that it is just loud or loose pawls. If I lubricate the freewheel with a light teflon oil, the sound gets worse. Sometimes the next day the sound goes away completely. If I lube it again, the sound returns. I am afraid to use a straight 20 weight non detergent oil as this once hung up the pawls on an old freewheel I had. You can't ever hear this sound while riding but as these freewheels are hard to find, I would prefer to avoid future catastrophic failure. What is happening to this old friend and what can I do to preserve her? Garth Libre in Surfside Fl.