So I am wondering about using some napa belden wires for a ford 460. I know they use 8mm for their tfi coils. I have been toying with the idea of doing some gap stretching and side gapping of my plugs. Does the stock coil output allow for a .040 or so gap at the plugs or am I just pissing in the wind with this whole idea. Thanks, Joe

 

I run MSD 8.5mm on mine, gapped at 0.35".

 

+1

The 8.5mm Red MSD wires are the best......IMHO.....Only 50ohms per foot and I don't know anyone else with that's kind of stats. Besides, they hold up to everything I have ever thrown a stick at including headers.

 

I gots a stupid question...

with the heavier wires, (I run Taylor 8.2's), is it the insulation that makes them thicker? Or, is it more filament that makes them thicker? Is it a little of both?

reason I ask, is heavier shielding would reduce the ability of the charge to ground somewhere NOT on a spark plug.. more filament would allow better path and less 'hot spots' during it's travel from dizzy to plug.. at some point, if the filament is too big, it would slow the travel of the spark to a point below usefulness- and would only be helped by using a stronger signal generator (stronger ignition).. The shielding would help no matter what..

so, is the filament a bigger gauge in heavier wires? If it is, then this is a paradox.. I mean, why increase amperage if you're effectively reducing it by using heavier filament? If you increased the amperage on a same gauge filament, you've increased the propensity for grounding before the charge makes it to the plug (compromising the shielding)..

I'm thinking the insulation is what is better, not a heavier gauge filament.. don't get me wrong, I bet it's a better quality filament.. but, in order to take advantage of stronger spark, the wisest move would be to match the signal to the conductive materials gauge/resistance, and shield it to the point of reducing or eliminating hot spots, bottle necks, and ability to otherwise compromise the path between dizzy and plug..

am I wrong?

If I'm not, ANY coils generated charge (spark) would be benefited by heavier gauge (shielded) wires.. Which means, the original question is answered by saying: go for it.. the gauge of the wire is insignificant to the spark of the coil.. any heavier shielded wire will increase the conductivity of the existing system, and provide better spark to the plug.. However, increasing spark generation (stronger ignition amperage) and NOT increasing gauge of wire, will increase the possibility of grounding somewhere between the plug and the dizzy..

 

No you don't. Spark plug wires are interesting little contraptions.

I've hacked up a fair number of plug wires, and the biggest difference is just the insulation thickness. 99.99% of the people who buy plug wires don't know how they work but they believe that thicker is better and lower resistance per foot is better, and manufacturers will play along because they're paid to do it.

Oh yeah, just so it's said: Resistance per foot is a worthless measure. Your coil throws a complex high frequency waveform down the wire, while your multimeter presents a trickle of battery current. That said, if you want smokin' hot plug wires gather up your terminals and boots and connect them up with some 18AWG 50kV wire. You'll get .008 ohms per foot (still a meaningless number!) and the best possible spark energy but your radio will be unusable and you might **** off or even kill your PCM.

Huh?

The energy flying down those wires is kinda sorta but not really a DC pulse with scads of high frequency components, and high frequency currents just love to travel along the outsides of conductors -- it's a thing known as the skin effect. The upshot is that the more surface area you can provide, the lower the impedance at high frequencies so the more energy makes it to the far end of the wire.

If I'm parsing that correctly and the "grounding" we're talking about is dielectric breakdown, the stuff that makes light shows around the plug wires, and current has doodly to do with it -- it's all voltage behind that phenomenon, and conductor cross-section doesn't make any difference at all.

With increasing current the risk of inductive losses goes up -- we're all familiar with inductive cross-fire, right? That's a current-related phenomenon, and to get it to happen you essentially create a rudimentary transformer. Where fatter plug wires serve to mitigate this it's not due to dielectric strength but due to increasing the separation between the adjacent conductors, and with the inverse-square law in effect a little bit of additional separation goes a long way. You can more carefully route your wires, or you can just throw some fat mumble-humblers on there and let 'em fall where they may. (That's my approach, BTW. The wire looms that came on the truck are on a shelf in the garage.) Distance is distance no matter how you get it.

So, to sum up: Ignition energy being comprised of high frequency components we want conductors that are very good at conducting them. Since plain old high voltage wire would spew tons of noise we need RFI suppression, but resistive plug wires (the cheapest ones you can get) really suck at transferring energy and don't last long. A helically wound conductor will transfer more energy than a spirally wound conductor, so go with that if you can justify the expense. Insulation diameter needs only to be sufficient to prevent dielectric breakdown and light shows under the hood at night so 7.5mm wires are sufficient for our stock ignitions, but because the insulation forces separation you can be more careless about wire routing and still avoid inductive cross-fire with thicker wires.

The cheaper "mag wires" are going to be more loosely wound than the better ones, so won't conduct energy as efficiently as better wires even if they have a lower resistance per linear foot. Again, we're dealing with high frequency energy, not the small DC currents your multimeter works with.

Phew. That was a lot of typing.

 

Lot of typing, but a lot of information. And I agree. The dia increase is better due to the circumfrence as Unregistered stated. The MSD also have a larger outer diameter of the insulation I suppose - it will not fit comfortably into the brackets that hold plug wires. I drilled them out to allow wires to fit.

I also changed to these wires on my Yota a long time ago as I got noise on radio, especially AM stations. Changing to these wires cured that problem. I also get longer life on the Yota, but since I just recently put them on Ram, I will have to wait and see. I always write down any repairs or sevice on each of my vehicles so I can track these things.

I went with the MSD as they appear to offer the larger diameter. I originally used the Bosh (6.5 or 7mm) on the Yota and they did not last long and always created noise on radio.

 

I believe aim4squirrels had a MSD ignition system in his rig, and took it out at some point, but not 100% sure. I have had excellent results formthe larger dia MSD wires for about 7 years, on everything from 99 dodge 318, 96 Yota 3.6L, 88 jag 3.6L, and 88 454 chevy. I run stock ignition coil and dist in each of these.

 

MSD makes the best wire I know of, and they stand by every product they make. I've had a MSD ignition on my 1998 Durango (I sold it) and they worked flawlessly. I've experimented on many builds and experimented on many engines. The fact of the matter is, MSD 8.5 mm Red have always served me respectfully and have never EVER left me on the side of the road.

I have installed a lot of different wires, different plugs and had everything from no starts to random firing. Simply put, you can stick whatever you want in a motor and you get what you put into them. You want some cheap crappy Bosch, or any other wires, then put em in, but when I'm drivin past you on the freeway you'll be thinkin, I wonder what he has in his?

I will be buying a new set of MSD myself. Besides MSD I only put in regular OEM and Mopar Performance.

But hey, if you want to fry your PCM or screw up your wiring then go for the 18AWG.........LOL........I'll be stickin to what works perfect.

 

I actually learned a lot in this thread... Thanks for the info guys..
As far as experience, I know the Taylors I'm running seem to do the trick, and a lot better than the autolites that hit the circular file recently..

 

Some posts have gone away. Lets leave the drama for the daytime soaps please.