Broken ignition rotor

[GMR911]

Driving out of my street today and engine just stopped. Took the cap off and found a broker ignition rotor(rev-limiting). The contact has broken off. The cap looks very good. I had a spare rev-liming rotor as well as a non rev-limiting rotor. I put both in and the car won't start with either. Could anything else happened when the rotor broke. The car previously ran excellent. Thanks Jerry

[Walter_Middie]

Jerry,

What kind of car are we working on? Mine has a rev limiting rotor too.

Not seating the rotor completely can cause interference with the cap and break the rotor.

Do you still have points? I'd check those, and I look closely at the cap to ensure it is not cracked, but that wouldn't keep it from running. If you have points, that would be where I'd start.

[Gordo2]

Check to confirm if your distributor shaft wobbles - indicating worn bushings.

Once the bushings wear out - the shaft can wobble to the extent that the rotor tip can hit the contacts inside of the distributor cap, causing the rotor tip to break off.

Good luck,

Gordo

[Dpmulvan]

Pull the distributor Jerry and make sure nothing broke off and fell into the case.

[gtc]

Originally Posted by Dpmulvan

Pull the distributor Jerry and make sure nothing broke off and fell into the case.

But make sure you set it to top dead center first, otherwise you will have a heck of a time figuring out where the rotor should point when you go to reinstall the distributor.

[GMR911]

I have a loose clip in the back of the distributor, this may have caused the cap to slightly move and get cocked that possible caused the issue. However I installed a spare non reving rotor and the secured the cap and it sill won't start. I pulled a plug wire and installed a spare spark plug and I am not getting any spark. Could the broken rotor cause either the coil or CDI to malfunction. The car is a 77 911 with a 3.0L ROW motor, hence the rev-limiting rotor.

[Walt Fricke]

If you don't get the rotor fully seated, it won't stay where it should be. I'm sure you toke the cap off again after the starting issues, and all looked fine. But grab the rotor and see if you can twist it around more then the centrifugal advance allows. If the rotor isn't aligned with the slot in the end of the shaft like it should be, the engine won't run.

[timmy2]

Did you change the cap? (Likely damaged by broken rotor)
3.0 in a '77 means don't follow the plug wire drawing in the engine bay as the rotor spins backwards to the original '77 rotor.
Check to see if wires are routed correctly for a 3.0

[GMR911]

Rotor seems to be fully seated. Does't seem to have any play in distributor shaft. Perplexed why there is no spark? What would lead this issue create a a non-spark issue. I have a spare used cap that I may change to see if that helps. Thanks for the feedback, Jerry

[theiceman]

Put a plug wire on the coil and test for spark. This will remove cap and rotor entirely from the equation

[Dpmulvan]

Jerry I have new caps and rotors and distributors if you need any parts Bob can swing by on Friday and pick them up. I'll shoot you a pm with my # Good luck I'm sure you and Bob can figure it out.

[tobluforu]

What ignition system do you have?

[GMR911]

I have a Bosch CDI and black coil. Dave, thanks for letting me borrow the parts. I should be able to find the culprit by switching out good parts. You probably heard from Bob that we tried 2 spare permatune CDI's and a black coil I picked up in Hershey and still no spark. Not sure if they are any good because I never tested them. We know there is 11.8 volts going to the cdi, we know there is pulse coming from the distributor. We did find the coil wire had no continuity so and we destroyed mine trying to fabricate a new one to no avail. Will see what happens when we switch out the parts. If the CDI is bad i need to figure out what to replace it with or have it rebuilt. Right no I am leaning toward sending it out to be repaired. Hopefully all the problem is the coil wire. If that is the case still not sure how the broker rotor impacted the coil wire. Maybe had a surge and burned it out? Thanks again for all the feedback. Jerry