Broken Ingition rotor or worn distributor bearings?

[jrfc3]

I am new to the forum so forgive me if this post is not the correct place for this question.
I have a 1982 911sc and this is the second time the distributor rotor has cracked. This car is new to me but I am not new to working on cars and I have never seen a rotor crack this way. The car does a backfire or two then dies with no restart. First time was a tow home. second time I was able to MacGyver the car home.

What I found is the distributor rotor jumped and hit the side of the cap which than snapped the alignment pin underneath, rotor slides on shaft which makes timing go off and engine stalls.

First time I think maybe a bad or aged rotor, this happened again with a new cap with a couple hundred miles.

Anyone else seen this?

[tirwin]

Did both rotors fail the same way?

First thought is the dizzy needs to be rebuilt.

What does the inside of the cap look like?

[steely]

Welcome to the forum! This is the place.
Check the dizzy for up/down slop. It should only be 1/16th".

[jrfc3]

the cap, both of the have a scratch on the side, like the rotor jumped the track. Let me see if I can measure the side movement on the shaft.

[jrfc3]

at rest the side to side play is less than 1/16. the in/out or up/down is more and when 'out' the side to side play is greater. OK looks like the bearings are done. Can they be changed or I need to do for a rebuilt?

[Charles Freeborn]

Sounds like worn bushings. Steve Weiner (Rennsport) has a service to re-build.
When they're worn it's near impossible to get a good tune - dwell wanders all over the place.
-C

[steely]

I recently re-shimmed mine by myself - the parts are available and it wasn't hard. This only takes care of the up/down axial travel.
I'd defer to what Charles says in the side-to-side dept - go for a rebuild or have someone evaluate it.

Check these out for some info:
Distributor About To Go?
DIY Distributor Repair
Normal amount of play in distributor shaft...?

[MattTHEpainter]

Barry Hershon - IAE Inc. Great guy, insanely knowledgeable, and get a recurve while you're there. Tell him Matt from CT sent you.

[jrfc3]

Thanks everyone for the great feedback. Sounds like I have some options here and need to do some homework. Next step is pull it and get some more specific numbers on the play and condition.