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HSChapter 84
U.S. imports of parts for spark-ignition internal combustion piston engines (non-aircraft) (HS 840991) totaled $657.9M in July 2026, traded with 70 countries.
Importers of Parts for Spark-Ignition Internal Combustion Piston Engines (Non-Aircraft) paid $44.5M in duties in July 2026 — an effective duty rate of 12% on $358.9M in dutiable value, based on actual customs collections rather than the published tariff schedule.
Last updated: July 2026 dataMexico dominates US imports under this heading, reflecting deeply integrated North American automotive supply chains where engine components — cylinder heads, connecting rods, steel forgings, and cast-iron parts — move across borders as part of just-in-time manufacturing. The schedule distinguishes parts by material (cast iron at 8409911040–8409911080, aluminum cylinder heads at 8409913000, steel forgings at 8409915081) and by end-use sector: road vehicles, marine propulsion, and residual applications each carry separate 10-digit lines. Japan and China are also significant suppliers, making this heading a focal point for Section 301 tariff exposure on Chinese-origin parts.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
18.5K shipments/mo
Classification depends on the part's principal design use, not its potential interchangeability. If the part is specifically designed and marketed for road vehicle engines, it falls under lines such as 8409911040; if designed for marine propulsion, 8409911060 applies. When dual-use is genuinely ambiguous, a binding ruling request to CBP is the most reliable path to certainty.
Yes. Many parts classified under heading 840991 that originate in China are subject to Section 301 tariffs. The applicable list and rate tier depend on the specific 10-digit HTS code, so importers should verify current Section 301 exposure for each line before finalizing sourcing decisions.
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Subheading 1 of 3 in heading 8409
Subheading 840991 · $657.9M of $1.1B
ImportsExports
Imports
$657.9MYoY · Pro
Exports
$237.7MYoY · Pro
12-mo low · imports
YoY · ProThrough July 2026. Source: U.S. Census Bureau.
HS10 import codes under this HS6 parent, each with its own page. Source: U.S. Harmonized Tariff Schedule.
| Code | Description | Import Value | Effective Tariff % | Dutiable Share | Duty Collected |
|---|---|---|---|---|---|
| 8409915085 | Parts for Sp-Ig Pst Eng for Rd Tr,Bus,Auto,Trucks | $428.2M | 6.34% | 56.66% | $27.1M |
| 8409913000 | Aluminum Cylinder Heads,Spark-Ign Pist Eng.for Veh | $104.4M | 2.00% | 20.89% | $2.1M |
| 8409919990 | Parts, Exc Conn Rods, For Sp-Ig Pst Engines, NESOI | $71.8M | 14.21% | 77.60% | $10.2M |
| 8409919290 | Parts for Sp-Ig Pst Eng for Marine Propulsion | $18.9M | 10.63% | 68.80% | $2.0M |
| 8409915010 | Conn Rods for Sp-Ig Pst Eng for Rd Tr,Bus,Auto,Trk | $15.8M | 5.07% | 68.76% | $799K |
| 8409911080 | Cast-Iron Pts for Spark-Ignition Pst Engines,NESOI | $8.8M | 12.46% | 91.95% | $1.1M |
| 8409911040 | Cast-Iron Pts F Sp-Ig Pst Eng F Rd Tr,Bus,Auto,Trk | $5.6M | 13.14% | 69.13% | $734K |
| 8409919910 | Conn Rods for Spark Ignition Piston Engines, NESOI | $1.5M | 13.39% | 96.63% | $194K |
| 8409919210 | Conn Rods for Sp-Ig Pst Eng for Marine Propulsion | $1.0M | 7.04% | 57.40% | $73K |
| 8409911060 | Cast-Iron Pts for Sp-Ig Pst Eng for Marine Propuls | $996K | 8.82% | 46.55% | $88K |
| 8409915081 | Stl Forg for Spk-Ign Pist Eng Tract/Bus/Auto/Truck | $974K | 5.87% | 55.13% | $57K |
HS10 export codes under this HS6 parent, each with its own page. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 8409914000 | Parts F Spark Ign Eng F Rd Tr, Bus, Auto or Trucks | $156.5M |
| 8409918000 | Parts for Spark-Ig Piston Eng, NESOI | $76.3M |
| 8409916000 | Parts F Spark Ig Eng for Marine Propulsion | $4.9M |
Import lines come from the U.S. Harmonized Tariff Schedule and export lines from Schedule B. The two are numbered by different agencies, so the same 10-digit code can appear in both tables describing a different product.
Imports · July 2026
origin
Mexico and Japan together supply 60% of it.
customs district
destination
entry
rate provision · imports
44.1% enters free of duty; the effective duty rate is 6.76%.