Long story short- after having had a set of AC/Delco spark plug wires on my stock '84 T/A for only 3 years, I've found that I'm having to replace them again. Engine started running bad, after doing continuity checks I found not just one but 2 wires had opens in them.....

What could cause this? Or is it just that AC/Delco wires aren't that great? Comments?

Thanks!

 

Hello Dave,

I have used AC Delco wires in the past with mixed results. So many things come into play in their longevity such as oils leaking on them routing of the cables, are the cables arcing are just a few questions that come to mind. I have found that the factory routing of the cables is not always the best way to route cables especialy in the older cars like ours. I have found neatness counts and using good seperators and wire looms help considerably when we are talking about ignition wire life. Truth be told my opinion of course I like the Autolite brand better than the AC/DELCO. Now I use the Taylor Cables that I bought from Summitt and they seem to be doing the job fine. Good Luck

 

The original wires are a carbon filament resistance core, and either 7- or 8mm silicone jacketed. Your AC/Delco (Packard Electric) wires are likely the same thing.

There is nothing inherently wrong with this type of wire. As Radiate mentioned, routing is important. Movement is what kills these wires and creates breaks (opens). Heat is not generally a factor unless they are lying against a hot exhaust surface. Once you have an open, it tends to arc internally and enlarges the gap in the break. If you route them to minimize movement from vibration, they'll last longer. Any good 8mm supression wire should do well on a stock setup.

 

Hmm- I've kept the original routing on the wires from the factory. The set that came with the car when it was new lasted about 7 years. The second set lasted 8, the third set only 3. It's now chewing on it's 4th set . But I'll doublecheck the routing on this and make sure everything's not loose. There was no pattern of failure, either- that is the same wire(s) didn't fail on each set, it was always different ones.

 

I use Taylor Spiro Pro wire, with the factory routing; I get over 100,000 miles out of a set. The ones in the car now have close to 100k on them and seem to work fine. Keeping them off the exhaust is key. I keep after the looms.

I did have a problem with them once.... I had an intermittent miss that I just couldn't seem to find; it would appear for a few days, than go away for months, then come back.... drove me almost over the edge.... finally I parked it somewhere completely dark, and watched under the hood while it ran; I discovered that on one of them, one little whisker of the core hadn't got cut right at the factory, and was sticking out the back side of the boot, and arcing to the head or exhaust or something. I guess anybody can have problems like that. Also a good object leeson in why just "I have new ones" doesn't always translate "I know for certain that they're good".