Jump to content
HybridZ

Seperating Spark Plug Wires


76280z

Recommended Posts

Does anyone have any objective data that supports this concern (that bundling the wires together will cause problems with coupling of the spark to other plugs)? I'm familiar with the phenomenon's affects but wonder if enough energy is coupled to the unintended wires to actually cause a large enough spark to cause ignition at the wrong time in another cylinder. I'd be curious to see data that shows this to be an issue with real ignition systems (as opposed to the theoretical discussions we had in my physics and EE classes).

 

BTW, I'm NOT saying this isn't a real issue (sorry for the double negative), but so far all we have are a few anecdotal examples that claim it can be a problem, and also a few claiming that bundling wires doesn't cause a problem at all. In the spirit of hybridz, can we get some objective data?

 

And in case anyone is wondering, yes, I have spacers on my wires :)

Link to comment
Share on other sites

Does anyone have any objective data that supports this concern (that bundling the wires together will cause problems with coupling of the spark to other plugs)? I'm familiar with the phenomenon's affects but wonder if enough energy is coupled to the unintended wires to actually cause a large enough spark to cause ignition at the wrong time in another cylinder. I'd be curious to see data that shows this to be an issue with real ignition systems (as opposed to the theoretical discussions we had in my physics and EE classes).

I have a real world example. Porsche 944 came into the shop I worked at and it would turn over 2 or 3 times and then fire at a REALLY wrong time and stop. It was like kickstarting a bike when the cylinder is in the wrong position if you know what that is like. Anyway, we searched around for quite a while trying to figure it out, finally I turned the lights off in the shop and sprayed the plug wires with water. Sure enough there were crossfires everywhere. With the lights on and without the water you couldn't see them, but the wires were old and were laying on each other for about 12", and that's where the crossfire was happening.

Link to comment
Share on other sites

Real world example, I've seen plenty of plug wires that have swiss cheese boots on them. I've seen some arc while the engine is running, little mist of water makes it all pretty obvious. I'm not a physics prof.... just a mechanic.

 

However, if we are on the subject of cool physics stuff relating to ign. sys components; Anybody here ever gone into the garage on a moonless night and run their I-6 engine to see the spark corona? Very cool, I did it a couple of months ago, one night with nothing better to do.

 

Spark corona is the faint bluish glow that radiates from the engine block around the base of the spark plugs. Somebody correct me if I'm wrong, but i think it's from the flood of ions penetrating the metal; immediatly following the townsend avalanche on the spark plug. Either way, it looks cool.

Link to comment
Share on other sites

I have a real world example. Porsche 944 came into the shop I worked at and it would turn over 2 or 3 times and then fire at a REALLY wrong time and stop. It was like kickstarting a bike when the cylinder is in the wrong position if you know what that is like. Anyway, we searched around for quite a while trying to figure it out, finally I turned the lights off in the shop and sprayed the plug wires with water. Sure enough there were crossfires everywhere. With the lights on and without the water you couldn't see them, but the wires were old and were laying on each other for about 12", and that's where the crossfire was happening.

Jon, do you think there would have been a problem if the wires had been in good condition? I'm wondering if the primary issue is wires with worn insulation?

Link to comment
Share on other sites

"However, if we are on the subject of cool physics stuff relating to ign. sys components; Anybody here ever gone into the garage on a moonless night and run their I-6 engine to see the spark corona? Very cool, I did it a couple of months ago, one night with nothing better to do."

 

Oooh, yup, cool. Ever seen a clear distributor cap? Put one of those puppies from JC Whitney on a Mustang once and there's just a Johnny Cash "Burning Ring of Fire" in there, and that was with a 70's vintage points ignition. I've seen MSD arc 6 inches or more. Yikes!

Link to comment
Share on other sites

Jon, do you think there would have been a problem if the wires had been in good condition? I'm wondering if the primary issue is wires with worn insulation?

Sure it was a condition issue. Would there have been a problem if the wires were new? I don't know. I'd guess not. I can say with absolute certainty that the likelihood of misfire lessens when the wires are separated. So why not separate them? Is having them tie wrapped together so important that you'd risk misfires for it? If you're a neat freak there are other ways to keep the wires orderly without having the heightened risk of cross firing.

Link to comment
Share on other sites

I have a real world example. Porsche 944 came into the shop I worked at and it would turn over 2 or 3 times and then fire at a REALLY wrong time and stop. It was like kickstarting a bike when the cylinder is in the wrong position if you know what that is like. Anyway, we searched around for quite a while trying to figure it out, finally I turned the lights off in the shop and sprayed the plug wires with water. Sure enough there were crossfires everywhere. With the lights on and without the water you couldn't see them, but the wires were old and were laying on each other for about 12", and that's where the crossfire was happening.

 

hey a friend of mine told me about that trick too...

 

glad to hear it works =)

 

he said it's usually the weather cracked rubber, and it's an indication of how good the quality of the insulation is from company to company if put under the same conditions.

 

:cool::icon14:

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...