Spark plug torque chart by thread size (NGK, Denso, Champion)
A 14 mm gasket-seat plug in an aluminum head takes about 18 to 22 ft-lb (25 to 30 N·m) by NGK's and Champion's charts; a 14 mm taper-seat plug takes far less, about 7 to 15 ft-lb. Without a torque wrench, all three makers say finger-tight plus about 1/16 turn for a taper seat, and up to 2/3 turn for a new gasket. Threads go in clean and dry.
Contents12 sections
Key takeaways
- Seat type matters more than anything: a 14 mm taper-seat plug needs roughly half the torque of a 14 mm gasket plug 1 2.
- The makers disagree: for a 14 mm gasket plug in cast iron, NGK lists 18.0 to 25.3 ft-lb, Denso USA and Champion 26 to 30 ft-lb 1 3 2.
- NGK says not to use anti-seize or lubricant on its plugs; anti-seize can change torque by up to 20% 4.
- Ford's TSB 08-7-6 '33 lb-ft' is the expected removal torque for 3V engines, not an installation torque 5.
- The engine maker's value comes first. Hyundai and Kia print 10.9 to 18.0 lb-ft for their engines in service bulletins 6 7.
Quick facts
| 14 mm gasket, aluminum head | 18.0–21.6 ft-lb NGK 1; 18–22 Champion 2 |
|---|---|
| 14 mm taper seat | 7–15 ft-lb Denso USA and Champion 3 2 |
| New gasket, by hand | 1/2–2/3 turn NGK 8; 1/4–1/2 Denso 3 |
| Taper seat, by hand | About 1/16 turn (all three makers) |
NGK (USA, Niterra)
| Thread | Seat | Head | ft-lb |
|---|---|---|---|
| 18mm | flat (gasket) | cast iron | 25.3–32.5 |
| 18mm | flat (gasket) | aluminum | 25.3–32.5 |
| 14mm | flat (gasket) | cast iron | 18.0–25.3 |
| 14mm | flat (gasket) | aluminum | 18.0–21.6 |
| 12mm | flat (gasket) | cast iron | 10.8–18.0 |
| 12mm | flat (gasket) | aluminum | 10.8–14.5 |
| 10mm | flat (gasket) | cast iron | 7.2–10.8 |
| 10mm | flat (gasket) | aluminum | 7.2–8.7 |
| 8mm | flat (gasket) | cast iron | — |
| 8mm | flat (gasket) | aluminum | 5.8–7.2 |
| 18mm | conical (no gasket) | cast iron | 14.5–21.6 |
| 18mm | conical (no gasket) | aluminum | 14.5–21.6 |
| 14mm | conical (no gasket) | cast iron | 10.8–18.0 |
| 14mm | conical (no gasket) | aluminum | 7.2–14.5 |
From “How do I install spark plugs correctly?”1. Values as published, not converted.
NGK (Australia)
| Thread | Seat | Head | ft-lb | N·m | Turn after finger-tight |
|---|---|---|---|---|---|
| 18mm | flat (gasket) | cast iron | 25.3 – 32.5 | 35 – 45 | – |
| 18mm | flat (gasket) | aluminium | 25.3 – 28.9 | 35 – 40 | – |
| 14mm | flat (gasket) | cast iron | 18.0 – 25.3 | 25 – 35 | – |
| 14mm | flat (gasket) | aluminium | 18.0 – 21.6 | 25 – 30 | – |
| 12mm | flat (gasket) | cast iron | 10.8 – 18.0 | 15 – 25 | – |
| 12mm | flat (gasket) | aluminium | 10.8 – 14.5 | 15 – 20 | – |
| 10mm | flat (gasket) | cast iron | 7.2 – 10.8 | 10 – 15 | – |
| 10mm | flat (gasket) | aluminium | 7.2 – 8.7 | 10 – 12 | – |
| 8mm | flat (gasket) | cast iron | – | – | – |
| 8mm | flat (gasket) | aluminium | 5.8 – 7.2 | 8 – 10 | – |
| 18mm | conical (no gasket) | cast iron | 14.5 – 21.6 | 20 – 30 | – |
| 18mm | conical (no gasket) | aluminium | 14.5 – 21.6 | 20 – 30 | – |
| 14mm | conical (no gasket) | cast iron | 10.8 – 18.0 | 15 – 25 | – |
| 14mm | conical (no gasket) | aluminium | 7.2 – 14.5 | 10 – 20 | – |
| new plug, flat seat (gasket) | flat (gasket) | any | – | – | about 1/2 – 2/3 turn after finger tight |
| new plug, conical seat | conical (no gasket) | any | – | – | about 1/16 turn after finger tight |
| M10 (packaging example) | flat (gasket) | any | – | – | M10:1/2 |
From “Spark Plug Installation - Torque Setting Specifications (image) + installation text”8. Values as published, not converted.
Denso (USA, DENSO Auto Parts)
| Thread | Seat | Head | ft-lb | N·m | Turn after finger-tight |
|---|---|---|---|---|---|
| 10mm | flat seat | cast iron | 7-11 | 10-15 | – |
| 10mm | flat seat | aluminum | 7-11 | 10-15 | – |
| 12mm | flat seat | cast iron | 11-18 | 15-25 | – |
| 12mm | flat seat | aluminum | 11-18 | 15-25 | – |
| 14mm | flat seat | cast iron | 26-30 | 35-40 | – |
| 14mm | flat seat | aluminum | 15-22 | 20-30 | – |
| 14mm | taper seat | cast iron | 7-15 | 9-20 | – |
| 14mm | taper seat | aluminum | 7-15 | 9-20 | – |
| 18mm | flat seat | cast iron | 32-38 | 43-52 | – |
| 18mm | flat seat | aluminum | 28-34 | 38-46 | – |
| 18mm | taper seat | cast iron | 15-20 | 20-27 | – |
| 18mm | taper seat | aluminum | 15-20 | 20-27 | – |
| any | flat seat | any | – | – | about 1/4 to 1/2 turn after finger-tight (no torque wrench) |
| any | taper seat | any | – | – | about 1/16 turn after finger-tight (no torque wrench) |
From “Spark Plug Installation | DENSO Auto Parts”3. Values as published, not converted.
Denso (Europe, DENSO Aftermarket)
| Thread | Seat | Head | N·m | Turn after finger-tight |
|---|---|---|---|---|
| M8 (Y type) | gasket | not specified | 8-10 | new ± 1; used ± 1/12 |
| M10 (U, N type) | gasket | not specified | 10-15 | new ± 2/3; used ± 1/12 |
| M10 stainless steel gasket | gasket | not specified | 10-15 | new ± 3/4; used ± 1/12 |
| M12 (SXU, X, XE, XU, ZXE, ZXU type) | gasket | not specified | 15-20 | new ± 1/3; used ± 1/12 |
| M14 (FK, J, K, KJ, P, PK, ... W, ZT type) | gasket | not specified | 20-25 | new ± 1/2; used ± 1/12 |
| M14 stainless steel gasket | gasket | not specified | 20-25 | new ± 2/3; used ± 1/12 |
| M18 (L, M, MA, MW type) | gasket | not specified | 30-40 | new ± 1/4; used ± 1/12 |
| M14 (PT, PTJ, T type) | taper seat | not specified | 20-30 | new ± 1/16; used ± 1/16 |
| M18 (MA type) | taper seat | not specified | 30-40 | new ± 1/4; used ± 1/12 |
From “Technical Overview DENSO Spark Plugs (Spark Plug Technical Poster, DESP11-UK20)”9. Values as published, not converted.
Champion (DRiV/Tenneco, USA)
| Thread | Seat | Head | ft-lb | Turn after finger-tight |
|---|---|---|---|---|
| 10mm | gasket (Y678) | cast iron | 8-12 | 1/4 turn |
| 10mm | gasket (Y678) | aluminum | 8-12 | 1/4 turn |
| 12mm | gasket (P678) | cast iron | 10-18 | 1/4 turn |
| 12mm | gasket (P678) | aluminum | 10-18 | 1/4 turn |
| 14mm | gasket (N678) | cast iron | 26-30 | 1/2 to 5/8 turn |
| 14mm | gasket (N678) | aluminum | 18-22 | 3/8 to 1/2 turn |
| 18mm | gasket (A678) | cast iron | 32-38 | 1/2 to 5/8 turn |
| 18mm | gasket (A678) | aluminum | 28-34 | 3/8 to 1/2 turn |
| 7/8" | gasket (A478) | cast iron | 50-55 | 1/2 to 5/8 turn |
| 7/8" | gasket (A478) | aluminum | - | - |
| 14mm | tapered seat | cast iron | 7-15 | 1/16 turn (snug) |
| 14mm | tapered seat | aluminum | 7-15 | 1/16 turn (snug) |
| 18mm | tapered seat | cast iron | 15-20 | 1/16 turn (snug) |
| 18mm | tapered seat | aluminum | 15-20 | 1/16 turn (snug) |
| any (reinstalled, used gasket) | gasket | cast iron and aluminum | – | 1/4 turn |
From “Spark Plug Torque Recommendations | Champion Auto Parts”2. Values as published, not converted.
How the makers’ charts compare
The charts above are copied as each maker publishes them, without conversion. They agree on the pattern: bigger thread, more torque; aluminum heads at or below cast iron; taper seats well below gasket seats. They do not agree on the numbers.
| Plug | NGK (USA) | Denso (USA) | Champion |
|---|---|---|---|
| 14 mm gasket, cast iron | 18.0–25.3 1 | 26–30 3 | 26–30 2 |
| 14 mm gasket, aluminum | 18.0–21.6 1 | 15–22 3 | 18–22 2 |
| 14 mm taper, cast iron | 10.8–18.0 1 | 7–15 3 | 7–15 2 |
| 12 mm gasket, aluminum | 10.8–14.5 1 | 11–18 3 | 10–18 2 |
| 18 mm gasket, aluminum | 25.3–32.5 1 | 28–34 3 | 28–34 2 |
Scroll the table sideways to see every column.
NGK is not consistent with itself either. Its US page prints 25.3 to 32.5 ft-lb for an 18 mm gasket plug in an aluminum head; its Australian chart gives 35 to 40 N·m (25.3 to 28.9 ft-lb) 1 8. Denso Europe gives 20 to 25 N·m for M14 gasket plugs with no head-material split 9, well under Denso USA’s cast-iron value.
Use the chart from the maker of the plug you are installing, and the engine maker’s value when there is one.
Gasket seat vs taper seat
A gasket-seat plug seals on its gasket, and the gasket has to be turned down to make a gas-tight seal: Champion’s 3/8 to 5/8 turn for a new one 2. A taper-seat plug has no gasket and seals on its tapered seat, so it needs far less rotation and torque. NGK’s chart drops the 14 mm aluminum-head value from 18.0–21.6 ft-lb with a gasket to 7.2–14.5 ft-lb conical 1.
Champion’s torque values are for new gaskets 2. A used gasket is already crushed: Champion calls for only a 1/4 turn to seal a reinstalled plug on its old gasket, in cast iron or aluminum 2.
The turn method, without a torque wrench
All the makers start the same way: screw the plug in by hand until it seats. NGK: “screw in the plug finger tight until the gasket meets the cylinder head” 1. Then:
| Maker | Gasket seat | Taper seat |
|---|---|---|
| NGK (Australia) | About 1/2 to 2/3 turn 8 | About 1/16 turn 8 |
| Denso (USA) | About 1/4 to 1/2 turn 3 | About 1/16 turn 3 |
| Champion | 3/8 to 5/8 turn with a new gasket, by head material 2 | 1/16 turn 2 |
Denso Europe lists the angle per thread size, from 1/4 turn for M18 to a full turn for M8, and 1/12 turn for a used plug 9. NGK Australia notes that the angle is printed on the plug packaging, except for racing plugs, which use the torque method only 8.
Anti-seize and lubricant
The plug makers’ torques are for clean, dry threads, and their advice on lubricant differs:
- NGK: plugs have trivalent plating that resists corrosion and acts as a release agent, and are installed at the factory dry. “Anti-seize can act as a lubricant, altering torque values up to 20 percent, increasing the risk of spark plug thread breakage and/or metal shell stretch.” Do not use anti-seize or lubricant on NGK plugs 4.
- Denso USA: values apply to new plugs without lubricated threads; if lubricated, reduce torque by approximately 1/3 3.
- Denso Europe: with oil or lubricant, use 2/3 of normal torque; Denso does not recommend lubricants 9.
An engine maker can override this. Ford’s TSB 08-7-6 for 4.6L, 5.4L and 6.8L 3V engines calls for new plugs to be installed with a film of Motorcraft high-temperature nickel anti-seize on the ground electrode shield, not on the electrode strap 5. The same bulletin’s “about 33 lb-ft (45 N-m)” is the expected removal torque. It gives no installation torque, so 33 lb-ft is not an install value 5. For more on compounds, see anti-seize and torque.
Engine makers’ values
Owner’s manuals rarely list plug torque, but service bulletins do for some engines:
- Hyundai Accent (HC): 14.7 to 24.5 N·m (1.5 to 2.5 kgf·m, 10.9 to 18.0 lb-ft), tightened with a torque wrench 6.
- Kia Theta II (2011–2013 Sportage, Optima, Sorento): 10.9 to 18.0 lb-ft (14.7 to 24.5 N·m) 7.
- Honda 2015 Fit: 22 N·m (16 lb-ft) 10.
- BMW turbocharged engines: removed and installed by hand and tightened to 23 Nm; “The use of pneumatic tools or improper installation torque can easily result in premature spark plug failure” 11.
Over-tightening is not harmless: NGK warns it can break the metal shell and damage internal seals, while under-tightening can overheat the plug and lead to detonation 1. See how to use a torque wrench for small values.
Sources
- 1NGK (USA, Niterra), How do I install spark plugs correctly?Checked 21 Oct 2026
- 2
- 3Denso (USA, DENSO Auto Parts), Spark Plug Installation | DENSO Auto PartsChecked 21 Oct 2026
- 4NGK (USA) - anti-seize guidance, 5 Things You Should Know About Spark PlugsChecked 21 Oct 2026
- 5
- 6
- 7
- 8
- 9
- 10
- 11
Spotted a value that doesn’t match its source? Report an error
Related
- Anti-seize torqueHow much to cut torque with anti-seize, from LOCTITE data sheets: copper and metal-free K 0.16, marine and silver 0.18, moly 0.11. And why NGK says no on plugs.
- How to use a torque wrenchHow to set and pull a click, beam or digital torque wrench, what ±4% accuracy means under ISO 6789, when to recalibrate (12 months or 5,000 cycles) and what not to do.
- Torque converterConvert torque between ft-lb, in-lb, N·m, kgf·m, kgf·cm and ozf·in. 1 ft-lb = 1.355818 N·m and 1 kgf·m = 9.80665 N·m, from NIST SP 811.
- AutomotiveAutomotive torque specifications quoted from manufacturer documents: lug nut torque by vehicle and model year, spark plug torque by thread, and oil drain plugs.