Distributor Cap - Uneven contact wear

Looking into my distributor for the first time.

  1. it appears that i have uneven wear on my distributor cap contacts. Could this be a worn shaft or misaligned shaft?
  2. the rotor/condenser doesn’t look like an old school point/condenser system - what is this replacement system?
  3. my coil has non-standard wiring, with the white w/black strip wire disconnected. Is this because of this replacement unit?


When you say “wear,”, do you mean uneven deposit of aluminum oxide on the contacts, or is there actual contact wear?

If the second, that strongly points to worn shaft bushings: that can easily be ascertained by grabbing the shaft and moving it side to side: if there’s any discernible movement, your shaft bushings are worn.

1 Like

This distributor had a Pertronix conversion. It’s fully transistorized, and requires no condenser. If you pull the rotor, you’ll find a reluctor ring. The cap may have been installed off center, or may have been out of spec from the outset. Just replace cap and rotor, making sure it’s aligned correctly and the clips snap down smartly. Then monitor the situation.

1 Like

worn distributor.pdf (1.7 MB)

It doesn’t look like a deposit, more like a chafing off of material. I tried to illustrate in the attached. One of the contacts looks brand new, the others have varying degrees of wear. The shaft will not wiggle. However, the cap is not so firm. It doesn’t take much force to move the cap. I am wondering if because the cap is not that rigidly attached, it was slightly offset causing wear because of an offset sweep of the rotor. How rigid are the caps on these distributors? Mine has two smallish spring clips at 12 and 6.

just coming to that conclusion!

I should also add that I’ve recently seen a lot of crappy caps. The most common problem is that plastic has been blobbed on the contact points. So inspect the new cap and clean up any plastic flash that’s out of place.

1 Like

Be aware that those things that you call “contacts” are not contacts at all, since they don’t actually contact anything and do not wear. If yours actually have metal missing then the rotor has probably been touching them due to a mis-aligned cap or worn bearings.

1 Like

Great ‘point’! I had a feeling something was off kilter. New parts as usual on order.

Try to find Bosch replacements. Also, Distributor Doctor sells the best replacement rotors.

The underside of the rotor is very very close to the Pertronix and looks like it has been rubbing, has this caused the offset arcing?

I agree that it might have been machined like this and the little sparks that do jump the gaps have eroded it further, especially where the gaps are larger. Just try a new one and see what happens first I would say.

Do you know if Pertronix uses a copy of a Lucas cap or is it proprietary to them?

I purchased one on Moss, it’s a proprietary cap.

The answer is yes, but what are we talking about now? A Lucas distributor with a Pertronix conversion, or a Pertronix distributor? If it’s a conversion it takes the same Lucas cap it always took (6478, 9523 or 9524). If it’s a Pertronix distributor, it’s still a Lucas cap, but you’d have to ask for something like a s2 or s3 XJ6 clip-on cap (9526), which is what the OP has.

No, it’s not.

I have a full distributor replacement

My mistake. I assumed when they listed it as “pertronics replacement” I assumed not an OEM replacement but a specific pertronics part. Thank you!