plug wires, correct me if i am wrong

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moparmat2000

moparmat2000

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I know this sounds stupid, and i should know the answer, mebbe i am thinking about this a bit late at night and am overtired, however when dealing with spark plug wires, Is the wire with the lowest number of ohms resistance is the most efficent transferring spark?

Thanks
Matt
 
Generally speaking, "yes."

You can get into "weirdness" with high power pulses. An example is YEARS and years ago

Champion plugs came out with their "booster gap" plug which was supposed to allow voltage to climb a bit across the gap and maintain power in the spark. I think it was meant to help fouling.

Anyhow, GM whether they "knew this or not" came out with a SHORT rotor in the distributor. This made the plug booster gap essentially worthless, and vice versa, that is, you didn't want both of them on the same engine!!

Here's something on this, if you can figure out how to read it

https://books.google.com/books?id=9...epage&q=of champion plug booster gap&f=false

and.........

http://firetrucksandequipment.tpub.com/TM-5-4210-230-14P-1/css/TM-5-4210-230-14P-1_615.htm
 
Ok for the resident spelling bee champ on this thread since i typed this original post at midnight. MAYBE !!!

Is this much better for you ! Now Geo do you have any insight to the question i asked, or just want to correct my spelling??
 
The reason being is i found some MSD 8mm wires in black pre made on summits website with 500 ohms per foot resistance. $39.00. I also found 8mm wires pre made on the net by a company called packard wire that boast 270 ohms per foot resistance. For $49.00. I am not brand loyal in some things including plug wires, i want what works.

I am using a recurved mopar electronic distributor, and a GM HEI 4 pin module to fire it with a pertronics ignitor 3 coil. High perf accel cap n rotor w brass contacts.
 
GEO said:
What the hell is mebbe ?

Sounds like something real ignorant to be#-o
Click to expand...

So instead of trying to answer the question, all you can do is be the spelling analionie
 
Looks like I better get a thesaurus for this thread.... High resistance in the secondary can help boost the spark at the plug but you stress the capability of other components in between. Direct ignition or coil packs don't have caps and rotors to worry about. They handle wires with resistance up to 20K ohms without much trouble. Much more than that and the spark looks for other paths of lesser resistance....
 
mguner said:
Looks like I better get a thesaurus for this thread.... High resistance in the secondary can help boost the spark at the plug but you stress the capability of other components in between. Direct ignition or coil packs don't have caps and rotors to worry about. They handle wires with resistance up to 20K ohms without much trouble. Much more than that and the spark looks for other paths of lesser resistance....
Click to expand...

Ok those systems can handle 20,000 ohms resistance by their very nature of design, however that is like comparing apples to oranges.

We are talking about a mid 70s small block mopar with an electronic distributor thats been modified to run a GM HEI module and a pertronics ignitor 3 which has a similar primary resistance as a GM HEI E coil, and a 45,000 volt output

I am talking about actual spark plug wire resistances, not coil on plug ignition. I'm sorry not trying to be rude but your answer doesnt seem relevant to the thread i started.
 
It's OK.. I can dumb it down... :)
Delivering the spark with low resistance wires does make it easy for the spark to get to the plug, but the higher resistance wire will create a greater voltage spike at the plug taking advantage of the other high performance components that would otherwise shoot their wad prematurely. Why have an HEI coil that can produce 45KV when your wires let it go at 25-30KV? Again depending on the quality of the cap and rotor as well as which design, brass or aluminum contacts, thickness of material etc... The higher resistance wires may be just what you need. Have you checked the resistance of what you currently run? Part of the idea behind the large HEI cap was greater distance between the posts to help prevent arcing to other cylinders in high humidity etc... Of course it also gives you a place to mount the coil... If you want to run lower resistance wires then you should up the gap or resistance of the plug to help achieve the spark your other components were designed to create.
 
Resistance helps reduce EMI by rounding the edges of the voltage and current waveforms. A sharp transition is rich in high frequencies including radio frequencies. The resistance also reduces the antenna nature of the cables.

While it takes a high voltage in 1000's of volts to initiate a spark, once started the gap voltage is 100V. Peak spark current for a good ignition is about 1/4 A. Because the ignition coil is designed as a transformer, it ends up being mismatched in impedance serving the spark current. Higher voltage coils are even more mismatched.

Typically if the total resistance from coil to plug is 9k Ohms or less, that is good enough. Spiral wound may be less, they use magnetic compound to help reduce EMI. They are more complex, and sometimes even use resistance sheath too. Simple, reliable is good.

If EMI is too great, it will mess with your radio, phone, EFI, if you have that, and even cars around yours.
 
mguner said:
It's OK.. I can dumb it down... :)
Delivering the spark with low resistance wires does make it easy for the spark to get to the plug, but the higher resistance wire will create a greater voltage spike at the plug taking advantage of the other high performance components that would otherwise shoot their wad prematurely. Why have an HEI coil that can produce 45KV when your wires let it go at 25-30KV? Again depending on the quality of the cap and rotor as well as which design, brass or aluminum contacts, thickness of material etc... The higher resistance wires may be just what you need. Have you checked the resistance of what you currently run? Part of the idea behind the large HEI cap was greater distance between the posts to help prevent arcing to other cylinders in high humidity etc... Of course it also gives you a place to mount the coil... If you want to run lower resistance wires then you should up the gap or resistance of the plug to help achieve the spark your other components were designed to create.
Click to expand...

Yes this seems to make sense. I was thinking lower resistance = more efficent hotter spark. But having the plug wires have a higher resistance helps build the voltage. I am piecing together and building this car now, so currently there is nothing as far as ignition system so far except for the components i mentioned having.

I am currently in the hunt for a 360 short block. I may have found one a mid 70s short block. The recipe is 360 dished slugs , and 65 cc magnum style aluminum heads with 2.02, 1.60 valves. Should end up at about 10.25 to 1 compression.
 
I doubt high resistance helps build voltage, there is little voltage drop since the current is virtually zero up to the point the plug ignites.
 
So bottom line with the ignition system i have collected up for this project,

i have an option of 8mm MSD premade wire set with 5oo ohm resistance per foot. $39.00

Or a set of packard wire 8mm premade wire set with 270 ohm resistance per foot. $49.00

Just trying to find out, what would be the better choice for the coin spent.
 
KitCarlson said:
Because the ignition coil is designed as a transformer, it ends up being mismatched in impedance serving the spark current. Higher voltage coils are even more mismatched.


If EMI is too great, it will mess with your radio, phone, EFI, if you have that, and even cars around yours.
Click to expand...

Yup. Impedance. Same reason "to some extent" that speaker impedances must be matched to an amplifier, or RF cable impedance IE antenna / cable / transceiver such as a CB radio

EMI..........it can even screw up YOUR OWN car
 
67Dart273 said:
Yup. Impedance. Same reason "to some extent" that speaker impedances must be matched to an amplifier, or RF cable impedance IE antenna / cable / transceiver such as a CB radio

EMI..........it can even screw up YOUR OWN car
Click to expand...

Thats all well and good to know, however since my strengths lie in sheetmetal, fabrication , body, and paint, as well as mechanical engine building , transmission building, however i am a bit weak in ignition knowledge, this is why i posed the question on the wires.

I have posted 2 different sets of wires i can go with. For my application which is street some strip with a basic electronic ignition, and a hidden audio system which will use my phone for music, as the car is radio delete.

This is why i am asking the question. The most efficent wire set that will work with my setup.
 
Get the ones that have a spiral core, for sure. With a good set of those, I'm going to say the exact ohms/foot does not matter. I've bought many sets of spiral core plug wire sets over the last 30 years and never checked the resistance. Have never had an engine run poorly due to plug wires, unless they were physically damaged, burned, or old and leaking sparks. I'd look more at the overall quality of the wires, especially how well the ends are crimped, how the boots fit both the plugs and the distributor, things like that. The last set of wires I bought were Accel Super Stock "5000 series" spiral core 8mm wires. 500 ohms/foot. Universal set that you assemble yourself, cost $52.00, and I was pleased with the quality. Just don't put "solid core" wires on it. That's really asking for all kinds of problems.
 
MSD makes great wire sets.
Buy them, plug them in, Vroom Vroom.
Next question. :)
 
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