That "split lock" is really not a split lock, it is the timing collar ring that holds the magnet that triggers the ignition. You can rotate it to set the timing. However, underneath that collar, I have three radially placed set screws that help with prop hub retention and to prevent any possible rotation of the prop hub itself. Then blue Loctite on the prop hub threads, let it dry over night, and it is on there until you take the radial set screws out and heat the prop hub to get it to come loose.

AV8TOR