Always thought the lock collar went up against the body of distributor so the shaft would not move up & down . . . usually there is a spot there for the roll pin to go through the distributor shaft . . . the gear won't move, as the distributor is held down on with the upper outside collar . . .
The dist shaft does not bottom out on the oil pump shaft, there is a lot of clearance there for the oil pump shaft to move up & down,, & it does,,fixed many of them with the lock collar like the OP. is doing. before, timing light jumps all over,, after, nice & steady
