Two summers ago I was crew chief for a Club Ford team out at Summit Point in West Virginia. We were running a Bosch rev-limiting rotor for a Porsche 911. One morning the car would only run on two cylinders...after 15 minutes of checking plugs, etc, I pulled the dizzy cap and found that the spring-loaded part of the rotor had let go, blowing out one-quarter of the cap and destroying two of the contact towers. Half the rotor was nowhere to be found...