TR6IX NGK Iridium Spark Plug | Genuine NGK Spark Plug

🔧 Product Description

NGK Iridium Spark Plug – Part Number: TR6IX

Iridium NGK spark plugs offer a longer service life than a standard nickel-tipped spark plug: while nickel-alloy plugs offer a service life of roughly 20,000-40,000km, NGK Iridium IX spark plugs offer a service life of up to 60,000km, so fewer replacements are needed over time despite the higher initial cost.

Precious-metal spark plugs like the NGK Iridium IX also offer higher ignitability, achieved with an exposed fine-tip centre electrode that promotes superior flame growth compared with a standard spark plug. Iridium has a much higher melting point (2410°C) than nickel (1453°C), allowing the centre electrode diameter to be reduced from 2.5mm to 0.6mm – a smaller electrode mass that reduces the impedance to flame progress, helping acceleration, fuel consumption and idle quality.

⚙️ Key Features

• Fine iridium-tipped centre electrode for a slow wear rate and stable idle
• Longer service life than standard nickel plugs
• Trivalent metal plating provides superior anti-corrosion and anti-seizing properties
• Corrugated ribs reduce the risk of flashover
• Pure alumina silicate ceramic insulator, providing superior strength and better heat transfer
• Copper core aids in heat removal
• Triple seals prevent leakage

📏 Specifications

• NGK stock number: 3689
• Thread: 14 mm
• Reach: .708"
• Hex: 16 mm (5/8 in)
• Seat: Tapered
• Terminal: Solid
• Type: Projected

🚘 Application

Listed in NGK's application charts for marine, motorcycle, ATV and snowmobile equipment and automotive vehicles. The chart shows a 1.0 mm gap for these engines, but check it against your engine's manual before fitting.

• Indmar 5.7L V8 CARB H.O. (8 CYL GM SMALL BLOCK) – Inboard Engine
• Indmar 5.7L V8 EFI H.O. (8 CYL GM SMALL BLOCK) – Inboard Engine
• Indmar 5.7L V8 GEN 1+ CARB (8 CYL GM SMALL BLOCK) – Inboard Engine
• Indmar 5.7L V8 GEN 1+ H.O. CARB (8 CYL GM SMALL BLOCK) – Inboard Engine
• Indmar 5.7L V8 GEN 1+ H.O. PFI (8 CYL GM SMALL BLOCK) – Inboard Engine
• Indmar 5.7L V8 LT-1 (8 CYL GM SMALL BLOCK) – Inboard Engine
• Indmar 7.4L V8 (8 CYL GM BIG BLOCK, 1999-1998) – Inboard Engine
• Indmar 7.4L V8 H.O. (8 CYL GM BIG BLOCK, To 1997) – Inboard Engine
• Indmar 8.2L V8 (8 CYL GM BIG BLOCK, 1999-1998) – Inboard Engine
• Indmar FORD 5.8L V8 285 H.O. (351 CID, 1997-1991) – Inboard Engine
• Marine Power L4 3.0L (181 CID, TAPER SEAT .708 REACH, 2000-1992) – Inboard Engine
• Marine Power V8 5.7L PREMIUM (350 CID, 1997-1992) – Inboard Engine
• Marine Power V8 7.4L (L29) (454 CID, 2000) – Inboard Engine
• Mercruiser 3.0L TKS (4 CYL GM) – Inboard Engine
• Mercruiser 3.0LX (4 CYL GM) – Inboard Engine
• Mercruiser 4.3L EFI GEN+ (6 CYL GM V-6, FROM 0L012009) – Inboard Engine
• Mercruiser 4.3L GEN+ (6 CYL GM V-6, FROM 0L010065) – Inboard Engine
• Mercruiser 4.3LH EFI GEN+ (6 CYL GM V-6, FROM 0L010044) – Inboard Engine
• Mercruiser 4.3LX GEN+ (6 CYL GM V-6, 0F803000 TO 0L000000) – Inboard Engine
• Mercruiser 4.3LXH GEN+ (6 CYL GM V-6, 0F803000 TO 0L000000) – Inboard Engine
• Mercruiser 5.0L EFI GEN+ (8 CYL GM SMALL BLOCK, FROM 0L015751) – Inboard Engine
• Mercruiser 5.0L GEN+ (8 CYL GM SMALL BLOCK, FROM 0L015751) – Inboard Engine
• Mercruiser 5.7L COMP GEN+ (8 CYL GM SMALL BLOCK, FROM 0L002005) – Inboard Engine
• Mercruiser 5.7L EFI GEN+ (8 CYL GM SMALL BLOCK, FROM 0L010035) – Inboard Engine
• Mercruiser 5.7L GEN+ (8 CYL GM SMALL BLOCK, FROM 0L010037) – Inboard Engine

That is the 25 most common of 76 applications NGK's charts list for this plug – ask us to check yours.

🔄 Supersession & Cross Reference

NGK's cross-reference tables list this plug against these part numbers.

• DENSO: 4714, 5326, IT20, IT20TT, T20ERR-U
• ACDelco: 12571165, 41-104, 41-812, 92143446
• Bosch: 9608, H7LDCR, HR6KII33X
• Torch: Q6RTP-11

📦 Condition

• Brand new genuine product
• Supplied in original packaging