Technical Looking for feedback on on clear red spark plug wires

I had no idea that you can get ignition rotors in different lengths? I have a friend of mine who almost burn his car to the ground due to his distributor catching fire. I always questioned what caused his distributor to burn up like that? I didn't question it that much though! His car looked like something outta mad max! Eben before the fire. He was running a stock HEI with an MSD conversion module and ignition box at the time.

 

Yeah the part number is the same (I think) on a Ford distributor rotor from '57 to '73, but when you buy one now, they are all noticeably shorter compared to the earlier NOS.

Or more likely if you order one under the older part number, they just provide the "updated" rotor. I suppose a feller could braze a br*** extension. It was causing or contributed to a lot of arcing to ground whenever humidity reached sauna levels in the summer. Took me a while to figure out.

I don't know that a mismatch in ignition components could start a fire, maybe. This stuff shows the importance of selecting ignition parts carefully, because it all has to work together, it's a total package deal. And brand new parts might look the same, but the QC isn't always there, or maybe the materials aren't up to the task.

On the other hand after 50 or 60 or 70 years, sometimes, the NOS parts that are still remaining today on the shelf, well maybe they were left there way back when for a reason. But those el-cheapo replacement distributor caps and rotors and points and condensers might not be an improvement over the genuine OEM. It might not fit quite right or the terminals aren't concentric, stuff that's hard to see sometimes.

I think it was Smokey who said they changed quite a few things when consulting (or racing?) for GM or whoever, but he said one thing they couldn't or didn't have to improve was the Ignition itself. Maybe it was in his "Lean Burn" days or something like that.

 

The spark will jump the gap as soon as the voltage is high enough to create a spark that long, under that (compression) pressure, with that particular fuel/air mixture. Think of the voltage as pressure trying to break through a barrier. Once it breaks through most of the pressure is gone.
The actual peak voltage never goes above what is needed to make the spark jump the gap, it just goes up until the spark can break through the gap, and then it goes down to a much lower voltage that can maintain the spark with current flow between the electrodes for about a millisecond or two (unless it's a CDI ignition, those sparks last much shorter).

Lean mixtures are indeed harder to light. Because of that the gap was widened on the spark plugs, a longer spark has a better chance of lighting the lean mix. Simple, right?

Downside 1: A wider gap requires a higher voltage to make a spark.

Also... The fuel makes the fuel/air mix slightly conductive. (This also means you can see the difference between a rich and lean engine if you look at the spark on an oscilloscope.) A richer mix needs less voltage to make a spark.

Downside 2: The "modern" lean mix bumps the voltage requirement up some more.

Downside 3: A higher voltage is better at breaking through any barrier, and jumping to ground (or something good enough) anywhere. The distributors were made in larger diameter to increase the distance between the different wire connections, to avoid the spark jumping to the wrong wire (and probably bigger distance from ground too, I guess). The higher voltage will also be better at breaking through the wire insulation, the insulation in the ignition coil, and so on.

So, the ignition system, i.e. the coil, any electronic box and so on does not decide what the spark voltage actually is. The system components decide what the maximum available voltage is, and that will only be reached if there is no spark - and we really don't want that to happen. Normally you get a spark at far less than the max available voltage, and that means you have a good margin for error - as in old plugs with wider than normal gaps, old carbon wires where the resistance has increased from age, and so on. Often they can keep running despite some things aren't good, but the increased voltage may eventually kill something else.

Have you noticed that the ignition coils in many modern cars, mounted straight on the plug fails pretty often? I'm guessing part of the problem is the location, the coil has to be small = limited room for insulation throughout it, and it sits inside a very hot engine, that's never good for plastic or electronics.
But the large spark gap, high compression (and/or turbo boost), lean mix those engines run has not given the coils a fair chance to begin with, even when everything is new. It's just something we have to live with, those coils WILL live a hard life, they have to to let the engine meet modern emission standards, fuel economy and so on. Some of those coils are bound to die quickly, especially when someone neglects to change their worn out plugs.

 

And all that airs is...
The Ed Sullivan Show
The Jackie Gleason Show
Rawhide
Some commercial with a little kid yelling, "I want my MAPO!"
Leave It to Beaver
QT Hush...

 

Using same set up. Never any problems

 

Yeah I've seen this using those "short" rotors and a good hot ignition coil, there was a half-moon arc being etched, or "carbon tracking" some might call it, right around around the rotor spring. The output from the coil wire at the distributor cap ****on, or maybe the spring, was just blasting through the rotor itself straight directly to ground (the distributor shaft).

I didn't know then what the cause was, that the initial coil firing voltage was spiking way too high, but hooking up an ignition scope showed this defect, then it was up to me to figure out why. I stumbled onto some webpage somewhere that 'splained rotor gap a bit.

The way I understand it, the largest physical air gap anywhere in the secondary circuit determines what the highest initial coil firing voltage will be, and ordinarily there are only two air gaps - plug gap, and the rotor gap.

Widening the plug gap is "good" (and so is the rotor gap I suppose) only so long as it doesn't leak to ground or misfire or arc somewhere else. Maybe an old points dizzy combo idles sweet as can be with a .060" plug gap, but, will it choke out on the highway or at high load and RPM?

Yeah I pondered that meself, because I noticed guys are constantly *****ing on other forums about replacing them. All of them.

Going from one round ignition coil to eight special, individually wrapped boutique designer coils at the plugs it would seem to me like they'd all be loafing along and last pretty near forever. You know, like the old round coils did. El-cheapo Manufacturing Co., LTD may be a part of this problem. Hard to find good help these days!

 

Thanks for the great pics of your setup! That's exactly how I'm setting it up, down to the same looms! Awesome looking engine!

 

Been running that way since 1990s Just replaced all wires and fuel lines last season

 

back in my day, when dino's roamed, those red clear wires with the copper wire were the hot setup for any hotrod. The early one's burned up super quick around any hot manifold, etc. True, they played hell with the radio but the quick fix was a std. suppression wire between the coil and distributor. Cool factor was off the charts.

 

They run fine on my friend Mel's 394. He bought a roll of the wire back in the 70's and has been running them ever since.

 

I had a red set on my nailhead for a short while but they really leaked spark all over the place, look good work not so good.