Install Spark-Plug Wires

Assembling MSD wires doesn’t require any special tools because a crimper is included, which mounts in a bench vise. Other wires may require a set of crimping pliers. You might need a tape measure or string, and a set of needle-nose pliers and wire cutters are always handy, along with a little spray lube and a marker.
Assembling MSD wires doesn’t require any special tools because a crimper is included,
There are two strategies you can use to avoid miswiring when adding a new set of plug wires. One is to remove and replace one wire at a time. Another option, shown here, is to trace each wire from the cap to its spark plug and make a drawing of each wire’s location on the cap for reference. If you’re working on an engine with no wires on it to start with, you’ll need to know the engine’s firing order, the direction of distributor rotation, and how the cylinders are numbered on the engine.
There are two strategies you can use to avoid miswiring when adding a new set of plug wire
After yanking off the old wires, we loosely installed the new ones on the plugs. MSD’s Heli-Core universal wire sets come with the spark plug terminal and boot installed on an extra long piece of wire so you can plan routing to the distributor to your heart’s content. We planned to loom the back three wires together with MSD wire separators, so pre-fitting them together allowed us to determine the correct length. MSD’s straight plug boots can be bent to a slight angle. They bend easier one way than the other, so lightly push and pull the terminal to find the easier direction and tweak it to the right angle-of-the-dangle for your application. They won’t go to 90 degrees, so buy fixed 90-degree plug boots if that’s what you need.
After yanking off the old wires, we loosely installed the new ones on the plugs. MSD’

Make sure that the wires won’t touch the exhaust manifolds, get caught in stuff like the fan belt, or get cut on sharp edges. Check that wires firing sequential cylinders (like 5 and 7 on most V-8s) cross at right angles (if possible) to prevent crossfire. Cosmetics are a big issue with plug wires--avoid big loops and use separators to keep them neat. Don’t make the wires so tight that you can’t remove the cap or rotate the distributor for timing adjustments. Once length is determined, cut one wire at a time then double-check the fit. If you cut it too short the first time you’ll be out of luck unless it will fit another cylinder.
Make sure that the wires won’t touch the exhaust manifolds, get caught in stuff like
MSD includes an aluminum tool for stripping and crimping the wires. It comes in one piece that you have to break apart in a vise, which is also required for crimping the wires.
MSD includes an aluminum tool for stripping and crimping the wires. It comes in one piece
To strip the wire, slide it into the stripper until it’s flush with the other side, then put a razor blade into the slot and rotate the wire. Remove the wire and pull the cut portion of the sleeve off with a counterclockwise twist to protect the conductor windings. It’s a perfect strip every time!
To strip the wire, slide it into the stripper until it’s flush with the other side, t

The socket-style (non-HEI-type) distributor connectors are brass and begin as straight terminals. Once they are crimped to the wire, slide the boot on and bend the terminal 90 degrees. The HEI-type terminals are straight and require no bending. With either style, fold the wire’s exposed conductor back along the sleeve and place the terminal so it sandwiches the conductor to the insulation as shown. Now you’re ready to use the crimp tool.
The socket-style (non-HEI-type) distributor connectors are brass and begin as straight ter
Position the terminal and wire into the crimp dies, making sure the conductor’s crimp tabs are facing toward the W-shaped side of the die. This is the side of the die responsible for bending the tabs to grip the wire sleeve. Before you start tightening the vise, check that the conductor is still in place between the terminal and the sleeve.
Position the terminal and wire into the crimp dies, making sure the conductor’s crimp
The crimp dies have tab ends designed to go on the outside of the vise jaws to stabilize the assembly while you apply pressure; this is important for an even and strong crimp. Slowly close the vise and watch as the dies come together. We also learned that you don’t need to run the die in completely--doing so tears the sleeve, which can cause a weak area resulting in spark loss. Putting a squirt of lithium grease or a dab of MSD Spark Guard on the W-side of the crimp tool helps smooth the crimp process.
The crimp dies have tab ends designed to go on the outside of the vise jaws to stabilize t

With the terminal crimped, spray a little white grease or WD-40 in the boot to make it easier to slide the distributor boot up the wire past the terminal. Using a pair of pliers, grip the terminal where it is crimped to the sleeve and press it down on the workbench bending it 90 degrees, then slide the boot into place.
With the terminal crimped, spray a little white grease or WD-40 in the boot to make it eas
These little MSD cylinder-number indicators slide on each wire easily with the weird little tool they come attached to.
These little MSD cylinder-number indicators slide on each wire easily with the weird littl
Using a marker to write the cylinder number on both the plug boots and the distributor boots can also help later.
Using a marker to write the cylinder number on both the plug boots and the distributor boo

Only once all the wires were routed did we snap the plug boots firmly in place. The air- conditioning compressor presented a bulky obstacle for us to work around for the front two cylinders and the coil, but we were happy with the way we handled it. If we would have used a “custom fit set,” the wires probably wouldn’t have fit as well as we like. The coil wire ended up being only about 6 inches long! Our very leisurely paced installation time was under two hours. A heavily modified V-8 shouldn’t take any longer. CC
Only once all the wires were routed did we snap the plug boots firmly in place. The air-

This one sure seems like a no-brainer, leaving us to wonder why so many street machiners have ugly, crossfiring, too-long, falling-apart spark plug wires. Maybe it’s because many "custom-fit" or "precut-to- perfect-length" plug wires are neither. That’s why, especially on a modified engine, we like to use universal or cut-to-fit plug wires and route the wires exactly where we want them for a cleaner job.

For this installation we used a Chevy 230 inline six, which is virtually no challenge for routing. Our real purpose here is to show you how to assemble typical crimp-yourself wires. Jacobs Electronics Energy Core wires have a simple no-crimp assembly process, but virtually every other type we’ve seen demands you use the process shown here on a set of MSD Heli-Core wires.