Ignition Wires 101, Part 2

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In our last issue we examined modern helically wound ignition wire in detail. We also showed you how to cut the wire to length and to strip it safely. This time around, we’ll examine the terminals and boots and take a look at various sleeve arrangements. Check it out!

MSD has a special dual crimp terminal that is engineered to grasp the internal wire sleeve as well as the conductor. The boots are manufactured from high temperature silicone. From the inside out, the dual crimp terminals (and boots) have these features:

Large crimp tabs grip the sleeve
Separate crimp tabs for the conductor
Snap lock plug grip
Extra material in each boot improves voltage isolation

In the accompanying photos, we’ll show you how the terminals and boots are crimped on the wires. But that’s not the end of it when it comes to ignition wires. Companies such as MSD (and others) offer a wide range of additional wire insulation. We mentioned the Pro Heat Guard sleeve in the first installment, but we didn’t include information on how you can seal the sleeve to the ignition wire. That’s where MSD’s part number 3407 Shrink Sleeves enter the picture. These are easy to use; once the wire is fitted with the Heat Guard, place a shrink sleeve over it to seal the gap between it and the respective boot. Use a heat gun to shrink it and you’re done. MSD also offers a smaller accessory numbered heat shrink. You can use these number shrinks over the Pro Heat Guard (the smaller wire numbers provided with the ignition wires won’t go over the larger diameter Heat Guard – at least easily).

Another consideration is MSD’s Pro Boot Guard. This is a thick, slide on sleeve engineered to withstand extreme temperatures encountered at the plug boot (obviously from the header). The secret is a special woven fiberglass inner core. The exterior is a uniquely high temperature compounded silicone rubber. MSD sells the Pro Boot Guard in 6-foot lengths. You simply cut it to size and then slide it over the plug boots.

Spark plug wires need to be separated. As MSD notes, “Not only do separators have to keep spark plug wires away from engine heat sources, they also have to keep the plug wires far enough apart to prevent inductive crossfire and actual spark loss.” This is certainly no secret to anyone reading this, we’re sure. There are all sorts of wire separators out there. Some are fixed. Others are freestanding. One of the easiest to use is the dual separator (part number 8841) from MSD. These separators will work with either 8-mm or 8.5-mm wire. They simply go over/under the wire and, as you can see in the accompanying photos, they’re designed to accept two wires. They also have a hole drilled through the center. This will work for some applications with wire stands (although MSD does not offer a dedicated stand).

As you can see, there’s a bunch more to ignition wire and accessories than first meets the eye. In the photos that follow, we’ll take a closer look at a selection of boots, terminals, wire sleeves, heat guard, wire shrinks and separators. We’ll also show you how to successfully crimp a dual-crimp terminal.

Website: www.msdperformance.com

In order to install the terminal, first pull the boot back over the stripped wire. A shot of WD40 (or a similar silicone-based lubricant, or in a pinch, dish soap and water) on the inside of the boot and along the outside surfaces of the wire allows the boot to easily glide back and forth on the wire. Pull the boot back so that you have some room to work.

Carefully bend the stripped-away wire back over the wire insulation and slide a terminal over the wire. The stripped-away wire should be positioned inside the U-shaped portion of the terminal. This ensures that the completed terminal is secure and delivers all voltage through the terminal. Using the crimping tool supplied with the wire set or MSD’s Pro Crimp tool, slip the terminal/wire into the area with the "W Crimp."

Slowly squeeze the handles of the Pro Crimp tool, keeping the open end of the terminal inside the jaws of the tool. The terminal will close securely. Just be sure that the stripped portion of the wire does not move during the terminating process.

If you’re using the supplied, tool insert it in a vice (as shown with the alignment tabs on the top of the vice). Slowly close the vice jaws. Make sure the tool remains aligned. Once the terminal ends have gripped the sleeve and the wire, stop cranking down on the vice.

This is the sleeve configuration from MSD. The design is similar to their earlier woven glass configuration; however, the exterior shell consists of a special silicone rubber coating. The ID measures 3/8-inch, which allows it to slide easily over most ignition wire. MSD claims their Pro-Heat Guard has a core that can resist temperatures up to 1,000-degrees F.

This is the sleeve configuration from MSD. The design is similar to their earlier woven glass configuration; however, the exterior shell consists of a special silicone rubber coating. The ID measures 3/8-inch, which allows it to slide easily over most ignition wire. MSD claims their Pro-Heat Guard has a core that can resist temperatures up to 1,000-degrees F.

A shrink sleeve is installed next. Don't forget this step! It's impossible to install shrinks once both boots are installed on the wire. Slide it back over the wire. This is also the time to install number shrinks. Again, slide it over the wire, but don’t heat it!

You can install the boot next. Slide it back over the terminal. If it feels stuck, give it another shot of WD40. Adjust the boot so the terminal is correctly oriented to the boot. Re-check to ensure the boot and terminal are aligned. A heat gun will effectively shrink the shrink sleeves (terminal ends and number shrinks). You can go too far with a shrink. Too much heat will actually distort the shrink sleeve material.

Here’s the Pro Boot Guard we discussed in the text. This product is simply cut to length and then slipped over the spark plug boot in order to provide additional heat protection.

One option to keep the wires tidy (and apart) are these dual wire separators from MSD. Installation is easy, per the lower photo.