Using the double nut technique, install the Studs permanently in the crank. The holes and threads must be very clean. Use LocTite620 to hold them in (if you don't, they will leak oil). Make sure the shoulder on the Stud squarely contacts the CrankFlange .On the CorvairListServe this was reiterated - the primary cause of oily prop without a FifthBearing is oil through the keyway and oil around the studs. The leak can be cured with a dab of RTV.