AE86 DENSO Spark Plug Set | 4A-C (1984-87 Corolla)

DENSO Standard U-Groove / Iridium TT Spark Plug Set

For 1984–1987 U.S.-Market Toyota Corolla Sport AE86 SR5 with 4A-C

Overview

This DENSO Spark Plug Set provides a complete four-plug replacement for the 1984–1987 U.S.-Market Toyota Corolla Sport AE86 SR5 with the factory carbureted 4A-C engine. DENSO supplied spark plugs for Toyota's original equipment, and the Standard U-Groove option offers a factory-style nickel-electrode replacement.

Choose Standard U-Groove for conventional nickel-electrode service or Iridium TT for a fine-wire iridium center electrode with a platinum-tipped ground electrode and greater resistance to electrode wear. Both options arrive factory pre-gapped for direct-fit use in the stock 4A-C: 1.1 mm for Standard U-Groove and 1.0 mm for Iridium TT. Neither option needs customer regapping for the stated factory application.

Key Features

• Factory pre-gapped options for stock Toyota 4A-C ignition systems
• Complete set of four matching spark plugs in either configuration
• Standard U-Groove nickel electrode for traditional factory-style maintenance
• Iridium TT fine-wire iridium center and platinum-tipped ground electrode for improved wear resistance
• Correct M14 × 1.25 thread, 19 mm reach, and gasket seat
• DENSO heat range 16 and resistor construction
• Direct-fit replacement for factory 1984–1987 Corolla Sport AE86 SR5 4A-C

Vehicle Fitment

Toyota Corolla AE86

• 1984–1987 SR5 (U.S.-Market) — 4A-C, manual or automatic transmission

Fitment Notes

• Factory 4A-C SOHC engine only
• Includes four matching spark plugs, sufficient for one complete 4A-C engine
• Does not fit factory 4A-GE-powered Corolla Sport GT-S models
• Modified engines or ignition systems are outside the verified factory application

Product Specifications

Brand: DENSO
Product Type: Spark Plug Set
Engine: 4A-C SOHC
Heat Range: DENSO 16
Thread: M14 × 1.25
Thread Reach: 19 mm / 0.750 in.
Seat Type: Gasket (flat seat)
Hex: 20.6 mm / 13/16 in.
Resistor: Yes
Factory Pre-Gap: Standard U-Groove — 1.1 mm / 0.044 in.; Iridium TT — 1.0 mm / 0.040 in.
Quantity: 4 matching spark plugs per set

Which Spark Plug Is Right for You?

Standard U-Groove — Best for Factory-Style Maintenance & Value

Choose Standard U-Groove if you maintain a stock AE86 SR5 on a conventional tune-up schedule and want an affordable, original-style nickel-electrode plug with DENSO's U-groove design.

Iridium TT — Best for Longer Electrode Life

Choose Iridium TT if you prefer a premium option with improved electrode-wear resistance over conventional nickel. Its fine-wire iridium center and platinum-tipped ground electrode are designed for consistent ignition over longer service intervals.

Prefer NGK? The NGK Spark Plug Set for 4A-C AE86 SR5 offers V-Power Nickel and Iridium IX alternatives for the same factory application.

Our Recommendation: Choose Standard U-Groove for factory-style maintenance and value, or Iridium TT for longer-wearing premium electrode technology. Both are direct-fit and factory pre-gapped for the stock 4A-C.

Available Configurations

Standard U-Groove

• (4) DENSO Standard U-Groove spark plugs

Iridium TT

• (4) DENSO Iridium TT spark plugs