I additionally secured my Solo muffler with a cable. The engine frame I have seen a good friend of mine breaking prop after prop when applying full power on take-off. After a very long and careful inspection, we found a broken tube in the engine frame which, pushed by the thrust at full power, allowed the prop to move too far and hit the cage. An engine frame must be checked often but especially after a hard landing and only after the harness and propeller cage have been removed. As stated above, hard landings as well as big vibrations or other abuse can lead to cracked engine frames.
Propeller cages The same rules apply to the propeller cages.
A good indication that something is wrong, is the clearance between the prop and the cage. This clearance should be even, all the way around. If it is not, a bent cage, a bent engine frame or a faulty silent block must be suspected. In addition, after a hard landing the cage may bend. Please note that at full power as stated earlier, the plane of rotation of the prop will change because of the thrust and torque reaction.