Hi all,

I had to replace one spark plug wire today because it was broken. I figured that my replacement has 4kOhms instead of 8kOhms like the others. All are 7mm.
Can this cause any problems? Should the resistance be the same for all wires? Car runs fine now.

Sorry if that's a stupid question, I'm a beginner..

 

Doesn't matter in the slightest. The resistance is only there for noise suppression. 4k will do just fine.

GD

 

Awesome, thanks for your response!
I'm super happy now as the car runs so much better and also proud I found the issue myself

 

4 THOUSAND ohms?? Sheesh! My spark wires are 270 ohms per foot...

 

Yes, 4KΩ. Many wires are rated to 2KΩ to 5KΩ per foot. It's not completely irrelevant, but nearly. It's what a friend of mine calls an "impractical truism" since it is so nearly irrelevant.

Ohm's Law is a physical law, not a theorem, suggestion, or guide. A little math with Ohm's Law will quantify the level of relevance. 30-40KV doesn't care one or two rodents' anteriors about a paltry little 4KΩ. The highly sensitive RF circuits in radios and TVs do, but certainly not the coil and not the spark plugs. The air gap of 0.060" is a LOT more resistive than 4K, or even 100K. Once the coil develops the voltage necessary to ionize the gap at the plug and create a plasma path for current flow, it's going to disregard a few hundredths percent additional resistance. That resistance will suppress any ringing, or secondary discharges, however, and that's just fine.

 

Or even their posteriors.

 

Rat-bellies are more susceptible to sensitivity, thus the metaphorical reference.

 

Now THAT is the sort of information I come here to get!