New ignition wires arching - any ideas ?

[TireNerdJr]

I just got my 325es a few months ago. After adjusting valve clearances I noticed a hesitation on acceleration and a popping on the radio. Sure enough I could see the old plug wires arching. I figured I aggravated pending cracks while adjusting the valves.

Ordered a new set of Karlyn wires from Pelican. At first everything ran great, then things got progressively worse between 50 and 100 miles. Now I can see arching in the new wires, but only when I rev the engine. The flashing is happening where all the wires are jumbled together just outside the distributor before entering the loom.

Any ideas? Defective set of wires?

Thanks for any help.

[thejlevie]

That would sound like defective wires to me.

[TireNerdJr]

BTW, for whoever might be searching on this topic, here's what I found:

The wires seem to be ok. A guy at work suggested that the spark plug gap might be too large or that the distributor cap / rotor could be worn. Both of these would increase the voltage necessary to create the spark. My plugs are worn and need replacing, but while waiting on new ones, I regapped the old ones. This seems to have solved both the arcing problem and problem with hesitation on acceleration.

It turns out that under high compression conditions, the voltage needed is higher (I haven't yet found a good explanation of why . . . anyone?). This is why the problem was only apparent under acceleration. The gap in the spark plugs was so large (up to 0.050 inches) that the easiest path was through the wire insulation, essentially robbing the cylinder of spark.