What is causing these deposits in my distributor?

[anwat]

This distributor only has a couple thousand miles on it. Something is obviously set up wrong here. I'm thinking there is some sort of arcing going on which is creating carbon? deposits on the contacts. Same thing around the center pin, looks like melted plastic. But it almost looks like molten metal slung around inside the cap. What have I done wrong? And I think I can answer this myself, but this cap and rotor are done, correct?

 

[imiceman44]

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This distributor only has a couple thousand miles on it. Something is obviously set up wrong here. I'm thinking there is some sort of arcing going on which is creating carbon? deposits on the contacts. Same thing around the center pin, looks like melted plastic. But it almost looks like molten metal slung around inside the cap. What have I done wrong? And I think I can answer this myself, but this cap and rotor are done, correct?

I have run worse on my engines before because I am cheap but if you want the best tune and mileage you are probably better off changing them.
I just clean em up and run the more

 

[anwat]

Until I figure out what's causing it, sandpaper willl be my friend. Those deposits aren't normal, are they? I've never seen those before, I' think I'm timed wrong...too much advance.

 

[Wes Harden]

That is a lot of slag. Not sure I have seen slung on to cap like that before.
My guess at this time is the gap between cap tower and rotor tip is to large. Try some moldeling clay to check gap

 

[imiceman44]

That is a lot of slag. Not sure I have seen slung on to cap like that before.
My guess at this time is the gap between cap tower and rotor tip is to large. Try some moldeling clay to check gap

Could also be the quality or lack there of the chinesium part

 

[nvrenuf]

What’s all that corrosion on the distributor itself? It’s even outside on the lip the cap sits on.

 

[anwat]

Not sure about the corrosion...there is a lot of rust inside the cap, I suspect some water got in there somehow, maybe through the vent. I have hood louvers, and got caught in a unexpected rain storm for a good four or five hours, so there was an opportunity for water to get in...hopefully not much, my oil looked ok when I changed it. One of the reasons I'm thinking about replacing that distributor once I figure out why it's arcing so much...If moisture did get in there, which it must have, would that cause those deposits? It ran fine through the rain, it was a few days after I noticed the cap corrosion. The inside of the cap and the rotor, everything in there looked brand new about 4 months ago when I last had the cap off.

 

[Blue85]

I have a few thoughts:

1. The distributor doesn't really seal from the engine because of how the shaft passes through it. This lets oil fumes and whatever's in the crankcase migrate in the distributor to an extent.
2. Getting water - especially dirty (i.e. ionized) water can lead to accelerated corrosion of contacts in the presence of voltage (electrolysis).
3. That's a weird rotor because it's adjustable. Changing the rotor phase won't affect timing (it comes from the position of the pickup coil), but it will affect the position of the rotor tip to the contacts during the spark event. If this is wrong, you will end up with too long of an arc at the highest or lowest timings. Yours *seems* OK since there is arcing all across the contacts

 

[anwat]

Update: Talked to MSD, they said this looks like normal wear to them and it's time for a new rotor and cap. No joke. The tech line a t FiTEch was a lot more helpful. They said it appears to be something they called 'spark scatter", which is caused by EMI in the wiring either from the pickup in the distributor or coming from/to the ignition box. This is causing the coil to send voltage at random times, basically creating arcing all over the cap. That plus the moisture did the cap and rotor in. I also noticed something iwasn't right with the reluctor wheel. it was actually touching the pickup with three vanes, and was pretty far away on three. The Shaft isn't bent, so I dont really know how that can be, but it is.
New distributor is here, we'll see how it fares now that I've shielded the wires with stainless braid grounded at one end. I had the wire to the ignition box running in a bundle with the main wire from the alternator to the distribution box, right past the coil wire and coil. So yeah, I can see some EMI there.