I4 (Inline 4) Ignition Wires - "IndestructaWires" - Shielded, Fiberglass Braid (1200 °F)

This listing is the high-temp jacket: woven fiberglass braid (~1200 °F continuous, ~2048 °F melt).
Finish note: The woven fiberglass braid has a matte, motorsport look and can hold fine shop dust more than silicone. A quick brush/air-blast and spot-wipe keeps it tidy; choose our Silicone-Coated version if you want a wipe-clean surface.

Custom-built, shielded & grounded I4 plug wires with ultra-low resistance and true copper-braid shielding. Designed for extreme heat/cold, physical abuse, and long life in real builds — from daily drivers to off-road rigs and high-heat engine bays.

Built to Order for Your Engine

Provide your engine and vehicle details (plus any relevant mods). We cut every lead to length, choose the correct boot angles and terminations, and build your set specifically for your application.

Toughness You Can Count On

Where most wires break down from heat, abrasion, or poor crimps, Shielded IndestructaWires are designed for survival. The fiberglass or silicone-glass jackets shrug off constant header heat, ceramic or silicone boots resist burning, and rigid high-temp heat shrinks provide lasting strain relief. These are not disposable wires — they’re built to outlast anything else on the market.

Why Shielding Matters

Many “low-noise” ignition wire sets rely on suppression rings or spiral cores that reduce interference, but they don’t eliminate it. Shielded IndestructaWires use 95%+ copper braid coverage, grounded to chassis, for verifiable EMI/RFI containment (20–60 dB typical attenuation). The result: radios, EFI, and comms stay clear even in off-grid or trail environments, while every bit of spark energy reaches the plugs.

Built as our flagship set, Shielded IndestructaWires pair a 95%+ tinned-copper braid (grounded) with an ultra-low-resistance core for bench-tested EMI/RFI containment (typical 20–60 dB; see our test sheet). These wires also have a distinct and customizable look that will be sure to "spark" conversations with fellow performance enthusiasts.

Materials & Construction

• Core: Ultra-low resistance (~0.04 Ω/ft)
• Dielectric Stack: >50 kV breakdown margin
• Shield: Tinned-copper braid, grounded pigtail (<1 Ω verified)
• Jacket: Fiberglass braid (~1,200 °F continuous, ~2,048 °F melt)
• Boots: High-temp silicone (~450 °F) or ceramic (~2,000 °F+)
• Terminations: Stainless terminals, matched to your distributor and coil
• Diameter: ~10.5 mm finished size with reinforced ends
• QC: Every set continuity-tested; shield-to-ground verified

Best For

• Classic and performance inline 4's with distributors (carb or EFI conversions)
• Tight header or turbo bays where heat kills ordinary wires
• High-heat bays (tight long-tube headers, turbo/downpipe proximity, trail heat soak)
• Off-road rigs needing physically rugged wires that won’t break down, while keeping radios and comms interference-free off-grid
• Builds with EFI, radios, or data systems where EMI noise matters

Options & Upgrades

• Ceramic plug boots for extreme heat
• This listing uses Fiberglass Braid (High-Temp). For Silicone-Glass, choose the “Shielded, Silicone-Coated” product.
• Color/finish options

What’s Included

• Four custom-cut plug leads
• Coil/HEI lead when applicable
• Ground pigtail with star washer hardware
• Ring terminals with heat shrink sleeves
• Dielectric grease packet
• Install guide, QC card, and warranty card

Install Notes

• Ground the shield near the distributor or coil with the included hardware
• Maintain at least 1″ clearance from headers or turbos
• Apply a rice-grain of dielectric grease in boots; seat by the boot, not the wire

Warranty & Guarantee

Every Shielded IndestructaWires set is backed by a 5-year materials and workmanship warranty — covering boots, jackets, crimps, and shield continuity.

Each set also ships with a complete documentation pack, including:

• Warranty card
• Quick start installation guide
• Quality Control & Test Sheet (verifying continuity and shield-to-ground integrity)
• Specification sheet for your exact build

We guarantee fitment when you provide your engine and vehicle details. If an issue arises, we correct it quickly and stand behind our work.

View Warranty Info Here

Optional: Quick Measure to Reduce Downtime

Want the best chance of a perfect first fit? If you have a usable set on the engine, pull and measure it before ordering. This helps us match your exact routing and reduces the chance you’ll need to send anything back for resizing. We include a complimentary first-fit adjustment on initial install.

How to measure (5 minutes):

• Label each wire by cylinder (and the coil wire if external)
• Measure center-of-terminal to center-of-terminal following the route you’ll use
• Note plug boot angle (straight, 45°, 90°) and the distributor/coil boot style
• Add any routing notes (loom location, tight spots)
• Snap a photo of your notes and upload at checkout (or email with your order #)
• If your current set fits poorly or is routed wrong, skip this—just give us your engine and details and we’ll build from scratch. Either way, if a lead needs fine-tuning on first install, we’ve got you with a complimentary first-fit adjustment.

Pro tips:

• Use a flexible tape, small rope, or a string for accurate path length
• Don’t add extra “just in case” slack — we’ll account for strain relief
• All wires will be routed slightly longer than your measurements to ensure that proper strain relief and routing is possible

Note:

Distributor-based ignitions only. If your four-cylinder uses coil-on-plug (COP), coil-near-plug (CNP), or distributorless/coil-pack rail (DIS), we do not currently build for it (common on many late-model Honda/Toyota/Nissan/Ford/GM I4s and most VW/Audi I4s after the late ’90s/2000s).

If your ignition uses uncommon or legacy terminals (early Ford rings, marine, industrial, etc.), please contact us before ordering. For one-off builds, send clear photos to confirm compatibility.