making spark plug wires...

[Steve Meltzer]

This should be a walk in the park, but things never seem to be that way for me. Enuf whining. No problem crimping the ends that fit over the plugs, but when I strip back the insulation so that a 1/2" of bare wire is folded over the wire, then jammed in the distributor cap, and screwed down, my VOM shows infinite resistance on some of the installed wires. Sometimes repeating the process will get me a reading that confirms continuity, but I've got one wire that I can't confirm carries electrons. thanx in advance. steve meltzer (this is on the Daytona with a spiral wound wire)

[Jimmyr]

Steve, measure the wire after it is striped but before you insert it into the cap. Since the core is much smaller diameter than the Belden or Packard solid stranded wires, hitting the conductor on these could take several tries with the cap screws. It is important that you see measurable resistance from the cap electrode to the plug end before completing the job. These wires are difficult to assemble, and it is equally important to measure the factory aftermarket sets before installation too. Also, pull and stretch the wire length while connected to an ohmeter to be sure the connections are tight!

[DWR46]

Steve: Insert the wire into the cap so the conductor is visible thru the screw hole. That way you know the screw is making contact with the conductor.

[Steve Meltzer]

thanx for the quick replies, guys. Just seems like it should have been so much easier than it's been. I'll get it....what I lack in intelligence (which is a lot!), I make up in tenacity. s

[tyang]

Isn't this the same car that you installed an MSD unit for? Doesn't MSD say not to use solid core wire for their boxes due to RF interference?

Tom

[Steve Meltzer]

yes and yes. You have a great memory and I'm impressed. Correct, one isn't supposed to use solid core wires, but these are spiral wound. thanx. s

[giovanni44]

Hello Steve,
I am going to plead ignorance on this one as it is the best excuse I can come up with. Could you please explain this-"one isn't supposed to use solid core wires, but these are spiral wound". What are spiral wound solid core wires and how do they evade the solid core rule?

Always learning,

Giovanni

[Steve Meltzer]

Giovanni, I'm sure you know more than I do about this and any of you EE's or physicists please chime in if I've messed up here. I'm using the MSD 6AL boxes and the directions say not to use solid core wires. Having dealt with this type of ignition wire before, the conductor is a solid wire, so it's verboten for this application. (Presumably because of EMI, electromagnetic interference.) The wires they recommend, and that I'm using, are "spiral wound". At a quick glance they may look solid, but if you start to pull on them, you'll quickly discover that they "unravel" because they are a helix. The conductor is very tightly wound around some sort of core material. Not sure if this helps, but that's how I understand it.
NB: I got a "C" in electromagnetic physics in college and, tho' it seems hard to believe a "B" in quantum mechanics. Go figure.

s

[DWR46]

We have installed MSD boxes on at least 100 different vehicles over the last 25 years. EVERY car had solid core wires (usually Packard 440). We have had zero problems, so apparently if you make the same mistake enough times it is no longer a mistake.

[Steve Meltzer]

HI Dyke, Wonder why MSD insists on the spiral wound, when your extensive real world experience clearly shows it doesn't
matter.

Just in from the garage where we got our first test of the Daytona's new MSD boxes and a set of all new plug wires.
(I bought the red, 7mm, spiral wound wire from Kingsborne). After getting the battery charged, the car fired right up and, for the first time since I got the car, it held a nice steady idle for as long as it was running (25 minutes). Dyke has been my advisor- in-chief on this project, sending me helpful emails and never giving up on our success. The turning point in the project was when he straightened out my thinking from a fuel problem to an ignition conundrum. Fixed now, so thank you sir, and onward through the fog! steve

[tyang]

It's not easy to pinpoint RF interference as there are many variables. There are some absolute truths, but a lot of variables. I think MSD found some problems with solid core wires and their use with the 6A boxes, and decided to eliminate the possible problem. I have heard of a Dino at another shop having problems with its 6A box where the problem was eliminated when switching out the solid core wires.

Tom

[Steve Meltzer]

From MSD's point of view, maybe there were problems with only one or two per hundred boxes, so if they say "use only spiral core wires" and they get 100% success, they'll say it. I sure didn't want to have to make another set of wires, tho' one gets better at making them after a few mess ups! Thanx again guys. s

[TOMKIZER]

Regarding making spark plug wires, and your original distributor cap end problem, I solved that problem with a little patience.

Most plug wire kits come with do-it-yourself crimp-on terminals. My terminals had a small hole in them opposite the split side, but if yours don't, you can drill them. I trimmed the wire insulation down to about 6 mm diameter with an exacto blade before folding over the core and crimping on the shortened and trimmed terminal. The terminal ends up being 7 mm diameter and slides into the hole in the distributor cap. By aligning the hole in the terminal with the pointed screw hole in the distributor cap, the wire gets "locked" into the distributor cap. The cut marks on the wire are all inside the cap and are not visible. The photos are of some old red 8 mm wires. 7 mm Packard wires that I replaced the red ones with were easier to make and required less trimming. The terminal makes a large surface area contact with the core wire and the screw makes good contact with the terminal by the point going into the hole. My terminals always made a very solid connection and stayed that way.

It's not a purist solution, but it's better than being stuck on the side of the road or driving home with a cylinder wall being washed by unburned fuel.

Good luck.

Tom Kizer

[Steve Meltzer]

So Tom, you actually use a terminal within the distributor cap, right? thanx s

[TOMKIZER]

Right! But you have to be careful. Make sure the terminal slides into and out of the distributor cap without resistance. The distributor hole is for 7 mm wire. If the terminal were to drag or stick in the hole, it could be pulled off the wire when trying to remove it and you would then have a devil of a time removing the terminal alone from the distributor cap. The little hole in the terminal was to make sure there was a place for the screw to penetrate without damaging its tip. I imagine those little screws are unobtainable now as stand-alone items.
Mine worked great for many years on both a set of red wires (incorrect for my car) and later a set of 7 mm black wires I made for Cavallino to reproduce original Ferrari wires for my car.

Tom Kizer