Materials

Wire, terminals, loom, heat shrink, and the small consumables. What each material is and where it's used. No brand names — automotive electrical specialists in any region carry these categories.

Wire

Primary wire (general circuits)

What it is: Stranded copper wire with insulation rated for automotive use — typically 105°C or 125°C continuous, abrasion- and oil-resistant.

Three common insulation types you'll encounter:

• TXL — thin-wall insulation. Used on most modern cars; saves weight and bulk in tight bundles. Suitable for general harness work.
• GXL — standard-wall insulation. Slightly thicker than TXL. Closer in feel to the original 1970s-era wire used on the S30 from the factory.
• GPT — thick-wall, older standard. Bulky in tight bundles; generally avoided on a modern rebuild.

For a full S30 rebuild, either TXL or GXL works. Pick one and stick with it for visual consistency. Avoid "hardware store" wire — it's typically THHN (house wire) with a 90°C rating, solid or coarse-stranded. It will harden and crack in an engine bay within a few seasons.

Wire gauge (AWG)

Smaller AWG number = thicker wire. Thicker wire carries more current safely. Match the gauge specified by the FSM for each circuit. Going thicker is generally fine but adds bulk; going thinner is unsafe — undersized wire heats up and melts the insulation under load.

Typical S30 gauges (verify against your FSM):

• Around 16 AWG for most signal and accessory circuits.
• Around 14 AWG for headlights and higher-current accessories.
• Around 12 AWG for fuse-box feed circuits.
• Around 10 AWG for the alternator output.
• 4 AWG or thicker for battery cables, depending on alternator output.

Battery / heavy-charge cable

What it is: Large-gauge stranded cable for battery-to-starter, battery-to-fusible-links, and (where used) alternator-to-battery main charge.

The modern default is welding cable (silicone or rubber jacket, very fine-strand copper) — it's flexible, takes vibration well, and has more current capacity per gauge than rigid-jacket battery cable. Standard PVC-jacketed battery cable also works but is stiffer.

Terminals & connectors

See the connector reference for the connector families used on the S30. To rebuild any one of them you'll need:

Open-barrel pin / socket pairs

Used inside multi-pin block housings, in 4 mm bullet connectors, and elsewhere. Sold loose by automotive electrical specialists; you crimp them onto the wire end with an open-barrel crimper. Buy a generous bag — you will mangle a few learning the technique.

Insulated terminals

Spade, butt, ring, and similar — sold as insulated (with a colored plastic sleeve) or uninsulated (bare metal). Insulated terminals are color-coded by wire-gauge range:

• Red — small wire (typically around 22–18 AWG)
• Blue — medium wire (typically around 16–14 AWG)
• Yellow — larger wire (typically around 12–10 AWG)

Match the terminal color to your wire gauge. Crimped with an insulated-terminal crimper.

Ring terminals

Bolt eye sized to fit the stud or bolt at each connection point. Sized for both wire gauge and bolt diameter — common bolt sizes on the S30 are M4, M6, and M8. A mixed assortment box covers most needs.

Connector housings

For multi-pin block, 6-wire block, and Bosch Jetronic 2-pin connectors, you'll need replacement housings if any are cracked or have damaged locking tabs. These are sold by Nissan-specialist suppliers and EFI-specific suppliers; the multi-pin and 6-wire types are not interchangeable with modern industrial connectors. Match your originals exactly.

Heat shrink

What it is: Plastic tubing that contracts when heated, sealing over a crimp or splice.

Two important variants:

• Adhesive-lined (also called "dual-wall" or "3:1 shrink ratio") — has an inner layer of hot-melt adhesive that flows when heated, sealing the joint against moisture. This is what you want for automotive work — engine bays see water, oil, and humidity.
• Plain (single-wall, 2:1) — just plastic, no adhesive. Fine for indoor electronics; lets moisture wick into the joint over time. Avoid for harness work.

Buy an assortment of diameters — small (around 3 mm) for individual wire splices, medium (around 6–9 mm) for terminal heels, larger (around 12 mm and up) for cable bundles or stretching over connector backshells.

Loom & sleeving

Cloth harness tape (period correct)

What it is: Adhesive cloth tape used to wrap wire bundles. The factory cloth wrap on a 1970s Z car looks and feels like this.

What it does: Holds the bundle together, provides modest abrasion resistance, doesn't unravel with age the way PVC tape does. Looks original.

How it's applied: spiral-wrapped along the bundle with around 30–50% overlap.

Braided polyester sleeving (modern)

What it is: A loose-weave braided tube that expands diametrically — slides over the bundle and contracts back when released.

What it does: Cleaner modern look, more abrasion resistance than cloth tape, easy to install in long stretches. Doesn't look factory-correct on a concours restoration but is common on resto-mods.

Split corrugated loom

What it is: Ribbed plastic tubing with a slit down its length. Slides over the bundle by opening the slit.

What it does: Heavy abrasion resistance, easy to install or remove later, common on modern cars in engine bays. Ugly in visible cabin sections; usually used in the engine bay only.

Combination approach

Many builders use cloth tape for the visible cabin sections (period look) and split loom or braided sleeving for the engine bay (durability). Decide your style up front so the materials list is consistent.

Other consumables

Solder & flux (limited use)

Use only if you're soldering — for example, an inline splice or repairing an internal solder joint on a relay. Standard 60/40 lead-tin or lead-free electrical solder. Not plumbing solder (different alloy, often acid flux that corrodes copper). Most harness joints should be crimped, not soldered — see the process page.

Dielectric grease

A non-conductive silicone grease applied inside connector housings before mating. Fills the small voids in a connector against moisture without affecting the metal-on-metal contact (the grease is displaced when the pins seat). Use a small amount on every connector during reassembly — it dramatically extends connector life.

Anti-oxidant compound

A grease (often copper-based) applied to ground points and large bolted connections to prevent oxidation between the terminal and the chassis. The chemistry differs from dielectric grease — anti-oxidant is mildly conductive and is meant for high-current bolted joints. Apply between the bare-metal mounting pad and the ring terminal during a ground refresh.

Zip ties & harness clips

For securing the loom to the body. Use UV-resistant black zip ties for visible sections; ordinary white nylon ties degrade in sunlight over a few seasons. Replace any factory plastic harness clips that are broken — these come as reproduction parts from most Nissan classic specialists.

Heat-shrink butt splices (occasional use)

Adhesive-lined butt splices that combine an insulated terminal and adhesive heat shrink in a single piece. Crimp once, hit with a heat gun, and the joint is sealed and insulated in one step. Useful for inline repairs where you don't want to retire and rebuild the whole wire.

A note on sourcing

The categories above are stable across decades — "TXL automotive wire", "adhesive-lined heat shrink", "ring terminals", "dielectric grease" describe well-defined product types that any automotive electrical specialist will carry. Brand names and which specific shop has the best price for a particular item change too often to be worth listing here. Use what's available in your region.

For Nissan-specific reproduction parts (multi-pin block housings, 6-wire block housings, Bosch Jetronic connector boots, period-correct fusible link blocks), look to specialist S30 reproduction-parts suppliers — these are genuinely niche items not stocked by general electrical suppliers. Forum recommendations are the most current source for who's reproducing what.

Sources & verification

The descriptions on this page are general automotive electrical knowledge. Specific suppliers and current pricing are deliberately omitted — they change too often to keep accurate.

• Nissan FSM — the Body Electrical (BE) chapter often specifies wire gauges and types for individual circuits. Free PDF scans of the FSM circulate on community archives; current links are typically posted in active forum threads on classiczcars.com.
• classiczcars.com — "Where to source X" threads stay current as suppliers come and go.

Spot something incorrect or unclear? Drop us a note.

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