• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Missing Graphite Electrode

Share this page

Rob Glasgow

Rob Glasgow

Jedi Knight
Country flag
Offline
My car seemed down on power today so I started to check the points. Opened the distributor cap, everything was coated with graphite, turned over the cap and guess what's missing???? Not a bit or piece remained. I'm amazed it ran at all. My question is "is the graphite electrode available by itself?" Does anyone know of a substitute for a quick fix?
 

Attachments

  • IMG_6180.JPG
    IMG_6180.JPG
    1.7 MB · Views: 179
Is it a Lucas cap? I used to have a broken Lucas cap; if I can find it--I'll check tomorrow--I'll see if I can extract the electrode. Can they just be pulled out? If it's not a Lucas cap it might not fit. FWIW, I haven't had great luck with aftermarket caps.
 
Bob, it doesn’t have any Lucas markings so I think it’s an aftermarket. I don’t remember when I installed it but probably over 15 years ago. I think I’ll drive down to Moss and pick up a new one.
I still don’t know how it manages to run with this part missing. I’m assuming the spark must have jumped from the primary cable directly to the rotor. Must have been pretty sparkling inside the cap.
 
Craig, Here you go. I found a used cap in my spares and switched the HT leads and am back in business. I did notice the electrode hole in the old cap was slightly larger than the one I replaced it with. Don't know if it was that way from the beginning. The failed cap had been on since 2006.
 

Attachments

  • IMG_6194.JPG
    IMG_6194.JPG
    1.3 MB · Views: 170
  • IMG_6191.JPG
    IMG_6191.JPG
    1.4 MB · Views: 172
On the failed cap, the spring was still in the bow but there was not one bit of the carbon electrode left. I had a new electrode and spring which I installed in the replacement cap. Thank you to the person who, on an earlier post about inserting the electrodes, suggested “winding them in at a 45 degrees angle”. It worked perfectly.
 
Rob Glasgow said:
Craig, Here you go. I found a used cap in my spares and switched the HT leads and am back in business. I did notice the electrode hole in the old cap was slightly larger than the one I replaced it with. Don't know if it was that way from the beginning. The failed cap had been on since 2006.
Click to expand...
I would replace the rotor also if you look carefully at it there seems to be arcing on either side of the brass contact.---???
 
I, of course, found a different problem with the graphite bit centered in the distributor cap. I had one jam up inside the hole, and it resisted every effort to remove it. I ended up damaging the cap and got a new one, a Lucas version.
 
What would be a suitable substitute for the graphite electrode nub? Something similarly shaped in brass - like #4 or #6 brass screw fit to length? Or perhaps a solid piece of copper rod?
 
RD, I noticed a small shoulder in the bottom of the electrode bore that surrounds the spring when inserted. If you try hard enough to push the graphite electrode too far into the bore, I can see where you could jam the soft electrode past that shoulder area and it would come stuck. Its a bit tricky to push it far enough to seat the spring, without jamming the graphite portion.
 
gonzo said:
What would be a suitable substitute for the graphite electrode nub? Something similarly shaped in brass - like #4 or #6 brass screw fit to length? Or perhaps a solid piece of copper rod?
Click to expand...
I think brass on brass would wear pretty fast; I'd stick with graphite (it's meant to be sacrificial). They should last 100K or more miles and usually the whole cap is a tune-up replacement item (or used to be).
 
Rob Glasgow said:
Bob, it doesn’t have any Lucas markings so I think it’s an aftermarket. I don’t remember when I installed it but probably over 15 years ago. I think I’ll drive down to Moss and pick up a new one.
I still don’t know how it manages to run with this part missing. I’m assuming the spark must have jumped from the primary cable directly to the rotor. Must have been pretty sparkling inside the cap.
Click to expand...
Rob,
Is Moss's storefront open? It was closed before for the virus.
 
steveg said:
Rob,
Is Moss's storefront open? It was closed before for the virus.
Click to expand...
Steve, I stopped by this past week and the sales office is still closed. I talked to a friend who works there and he was not sure when they were planning on opening. He has been working remotely and doesn’t miss the compute.
 
Back
Top