'78 SC Distributor Gurus - Is this noise normal?

b. hilliard · 08-30-2025, 07:54 AM

Hi all-

This is a follow-up question to an ongoing problem I've been having with my '78 SC that is running but cutting out when warm/ backfiring/ igniting out of the intake. Please see this post if you'd like a little background:

https://forums.pelicanparts.com/porsche-911-technical-forum/1182662-help-request-78sc-smoke-out-intake-quit-running-its-not-cdi.html

Got the car running with lots of other diagnosis possibilities "out of the way". When the timing light was on, 5' TDC seemed to jump around a bit AND the light flashes were not always consistent, like the #1 cylinder may have been misfiring. I pulled the distributor to check continuity/ resistance at the pickups and found this noise when spinning it by hand. Here is my new question: Does anyone know what this means? There seemed to be very little axial or vertical movement in the bushings, ie it was tight. Should I open it up and clean/ lubricate the bushings somehow? Does it need a full rebuild or replacement? See link below.

https://cdn.mileshilliard.com/porsche.mp4

b. hilliard · 10-27-2025, 07:56 AM

Hi all, update time in case anyone is interested.
I decided the odd noises heard by rotating the distributor (shown above) were decidedly NOT normal despite never having torn one down. I ordered a full rebuild kit from PartsKlassic and dove in. What I found was a distributor whose advance mechanism (both mechanical and vacuum) had frozen from corrosion/ lack of lubrication, and shims/ spacers that had long departed allowing axial play. Long story short, with a few head scratchers along the way but plenty of patience, it was rebuilt and feeling proper. I traveled to where the car was being stored, installed it and set the timing. Instantly I knew it was better as the timing no longer jumped around/ skipped and was easy to dial in. Also, my tach needle STOPPED BOUNCING! I crossed my fingers and drove the 200 miles home with no backup plan other than a Hagerty Insurance roadside coverage. The car ran great, really great, likely better than it has in LONG time and I've owned it 24 years.
Cheers!