Arcing at distributor

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MrJLR

MrJLR

Built, not bought
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I'm getting electrical arcing at the distributor ...When I grab the top of the dizzy to adjust timing, I'm getting zapped....!

I think I know the answer, but this is NOT good - right?
It's been running kinda funky and it occurs to me THIS probably has a lot to do with it....

I bought Taylor 8mm cut-to-length wires and made the ends up REAL careful....but I guess something ain't right.... I'm gonna try a standard set of off the shelf wires.....

Anyone recommend a set? On my dizzy the wires need to be female...

I bet this is why it's running funky....sometimes ya don't see the forest for the trees...!

Jeff
 
Electrical current will take the path to ground that has the least resistance. So somehow your body is grounded better than a wire or the cap ( cracked caps do this too ).
I recall Ford 5.0s with split/torn up wire boots that would idle perfect but... jack up the rpm and sparks would jump from wire to wire at the spark plug ends.
 
Whenever there is an open in the high tension circuit, you get arcing. Such things as burning the electrode off a plug, an plug that is cracked, bad connection ANYWHERE "in the chain" including the coil, dist. center tower, problems with the rotor, on and on.

Take all the wires.......including the coil, and clip your ohmeter to each end. "Shake" them while connected which will help show up "bad spots" in the length of the wires. Gently move the ends looking for drastic changes in the meter reading. "The old rule" of thumb used to be that a good wire was less than 1000 ohms per foot of wire. Almost any newer wire I've come across is far below that reading.

Other things that can cause arcing is such things as a bad cylinder.......burned / open valve, causing a lean condition, or a bad intake vacuum leak causing a lean cylinder
 
Hi powered ignition systems like HEI can burn a hole right through a rotor and arc to the distributor shaft.
Then when it does it and you are handling the distributor, you can get some of it while it's on it's way to the grounded block .
 
Wow....seems there's a LOT of possible reasons.....
I just assumed I did something wrong making up my wires.....

Jeff
 
MrJLR said:
Wow....seems there's a LOT of possible reasons.....
I just assumed I did something wrong making up my wires.....

Jeff
Click to expand...


Could very well be an improper end connector. I don't know how yours work. "Some" require stripping insulation to the core, folding it back into the connector.


If the trouble is one cylinder, plug, or wire, you can try a grounding probe. Pull the distributor boots loose. "Rig" a grounding probe. you can use a 12V test lamp or a small screwdriver and alligator lead. Ground each tower one at a time and see if the arcing goes away. "that cylinder" is your trouble.
 
67Dart273 said:
"Some" require stripping insulation to the core, folding it back into the connector.
Click to expand...

Yes....that's how I made my wires....and I was really careful...good solid crimps etc....
I'm wondering if it's my cap.....

Jeff
 
TQ probably not the reason.... your getting to the bottom of it :)
 
I had the same issue when my rotor was way out of phase. I corrected it using the MSD adjustable rotor kit. Later, I was told that some MSD distributors had the wires switched for the pick-up, and this would cause the distributor to spark out of phase. I switched them, but have yet to verify any changes due to a mechanical issue with the motor.
 
jbc426 said:
I had the same issue when my rotor was way out of phase. I corrected it using the MSD adjustable rotor kit. Later, I was told that some MSD distributors had the wires switched for the pick-up, and this would cause the distributor to spark out of phase. I switched them, but have yet to verify any changes due to a mechanical issue with the motor.
Click to expand...
Hmmmmm.....that's interesting. .....
 
Out of phase probably wouldn't shock you through the distributor housing though, unless it was able to jump to it from being out far enough.

An FYI just in case:
Out of phase means that when the distributor tells the coil to fire the rotor tip is not next to the terminal inside the cap, but sometimes so far away from it that the spark may go somewhere else. (like another terminal for a different cylinder that isn't supposed to be firing) or even possibly the distributor metal itself, but usually through the rotor since that path to ground is closer to the spark source in the center of the cap.
This rotor burn through was really common on the old large cap GM HEI ignitions.
 
TrailBeast said:
Out of phase probably wouldn't shock you through the distributor housing though, unless it was able to jump to it from being out far enough.

An FYI just in case:
Out of phase means that when the distributor tells the coil to fire the rotor tip is not next to the terminal inside the cap, but sometimes so far away from it that the spark may go somewhere else. (like another terminal for a different cylinder that isn't supposed to be firing) or even possibly the distributor metal itself, but usually through the rotor since that path to ground is closer to the spark source in the center of the cap.
This rotor burn through was really common on the old large cap GM HEI ignitions.
Click to expand...

It sure as heck went through the cap of my distributor. That dang thing hit me at least 10 times before I could get my hand off it, and that was with it idling. The problem I had was the result of running a MSD Digital 6AL with a MSD Ignition 8253 Blaster HVC II Coil. The thing gave me ten of the hardest shocks I've ever felt. It went all the way up one arm through my back and down my other arm to ground with an audible snapping noise for each hit. I just thank God it wasn't rev'd up.

It had even melted the tip of a rotor on my maiden lap at Willow Springs one year.
 
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