Plug Wires with MSD

gsjohnson · Post by **gsjohnson** » Fri Oct 10, 2008 11:36 pm

I just received my second MSD box from Jegs and I now have instructions. I already installed a 6AL MSD box on the passenger side as I had that MSD box lying around from another project.

After viewing the instructions, it states solid core spark plug wires CANNOT be used with MSD ignition. My car currently has the Packard 440 plug wires on it. Aren't those tin coated copper solid core wires? If so, what other alternatives do I have? The instructions further state a good quality helically wound or spiral wound wire must be used. So who out there has experience with MSD on their vintage Ferrari? All opinions welcome...

8339 · Post by **8339** » Sat Oct 11, 2008 7:53 am

We've installed a lot of MSD boxes on vintage Ferraris with great success. The reason you can't use solid core wires is too much RF fequency emissions. The first MSD I installed on my own car I used solid core wires and I could not get the car started. I called MSD and that's where I found out you have to use noise supression plug and coil wires. The MSD box is very sensitive to whats called RF frequency spurious emissions, I'm sure Tom Yang can explain that better than I can, however I understand it to be radio frequencies with no specific wavelength.

Richard Garre, Radcliffe Motorcar Company

Post by **tyang** » Sat Oct 11, 2008 8:47 am

Hi GS,

Richard explained it well. All that scattered RF from the solid core wires must affect how the MSD box works in sensing and triggering spark. Imagine 30K volts of RF being broadcast over what are essentially are 12 radio antennas!

7mm wires are the only diameter that will work with your spark plug tubes. Thread the six wires through the tubes leaving enough excess on each end to get to the plugs and the distributor cap. Rubber grommets insulate the wires from the opening on the tubes. Use lots of lube. Mount the tube to the cam cover and cut the wires to length with the caps installed to the distributors. Although they dry rot off pretty quickly, there are a couple of o-rings that keep the wires bundled together near the distributor caps.

Tom

gsjohnson · Post by **gsjohnson** » Sat Oct 11, 2008 10:39 am

Okay...So are these Packard 440 Wires that I currently have, solid core wires and can't be used?

And, does someone have a recommendation for a proper spiral or helically wound plug wire in 7mm?

As always, thanks in advance.

Jimmyr · Post by **Jimmyr** » Sat Oct 11, 2008 10:53 am

Another note to add to the RF problem; do not have the distributor pick up wire or the 12 volt + wires anywhere close to the HV wires. Dress them down and away from these high tension sources. Always be sure to use a resistave HV wire from the coil to the cap. In some cases you may be able to keep the solid core wires if the former wire routing works. Jim

8339 · Post by **8339** » Sat Oct 11, 2008 3:19 pm

GS, if you strip back some of the insulation on the plug wires, is there a few strands of copper wire or is there, for lack of a better term, nylon rope coated with carbon? Typically, noise supression wire uses a glass cord strand coated with carbon. The carbon conducts electricity but at a hgher resistance reducing the RF freq. If your plug wire has the glass cord you should be okay, if it's copper wire you'll probably need to change it. NAPA of all places carries 7mm noise supression spark plug wire in black, part# bel 7346001. You'll have to make up a set as Tom mentioned. You'll also need 12 spark plug terminals and 2 coil terminals. The spark plug terminals, again from NAPA are part# 727005, the coil terminal is #727003. Don't forget the plug and coil boots.

Richard Garre, Radcliffe Motorcar Company

gsjohnson · Post by **gsjohnson** » Sat Oct 11, 2008 6:11 pm

8339 wrote:GS, if you strip back some of the insulation on the plug wires, is there a few strands of copper wire or is there, for lack of a better term, nylon rope coated with carbon? Typically, noise supression wire uses a glass cord strand coated with carbon. The carbon conducts electricity but at a hgher resistance reducing the RF freq. If your plug wire has the glass cord you should be okay, if it's copper wire you'll probably need to change it. NAPA of all places carries 7mm noise supression spark plug wire in black, part# bel 7346001. You'll have to make up a set as Tom mentioned. You'll also need 12 spark plug terminals and 2 coil terminals. The spark plug terminals, again from NAPA are part# 727005, the coil terminal is #727003. Don't forget the plug and coil boots.

Richard Garre, Radcliffe Motorcar Company

Thanks for the response Richard. The packard 440 wires have copper core strands that are tin plated and I believe them to be solid core wires. I was looking at the Pertronix spiral wound 7mm wires.
http://www.jegs.com/i/Pertronix/751/708180/10002/-1

Deane · Post by **Deane** » Wed Oct 15, 2008 6:58 pm

Packard 440 is definitely solid metal core, non-resistance type.

gsjohnson · Post by **gsjohnson** » Wed Oct 15, 2008 8:46 pm

Deane wrote:Packard 440 is definitely solid metal core, non-resistance type.

Thanks Deane.
I ended up buying two V8 Pertronix Universal 7mm black spiral wound sets with the straight spark plug boots. Both sets cost me $80 from a local distributor. These Pertronix universal sets come with the spark plug ends and boots already assembled. The cutting and fitting is all done at the distributor end of the wires, which is perfect for us vintage F-car guys because we just screw the wire to the distributor cap. Just cut to length needed and you're good to go.

gsjohnson · Post by **gsjohnson** » Sun Oct 19, 2008 8:32 pm

Update:
Here is a pic of the new Pertronix wires installed in the tube to the proper length. I matched the old wire lengths for cutting the new wires and added an inch to be safe. Note the Pertronix wires have no writing on them and are 7mm so they will fit in the tubes. Silicone spray is your friend for feeding the wires into the tube with the new grommets. These wires from Pertronix are really perfect when performing an MSD conversion. They are a spiral wound stainless steel alloy. I cleaned the distributor caps up and cleaned all of the contacts. I even added the cylinder number stickers from Parker Hall.