Article C5.1.7
Cylinder Head Inserts
Technical Regulations
Article C5.1.7
Cylinder Head Inserts
Chapter: C5
In Simple Terms
F1 engines can only use FIA-approved metal inserts in the cylinder head to protect the valves and guides. These inserts must be small—the seat and guide inserts combined can't take up more than 3% of the cylinder head's total volume, with an extra 1% allowed for other types of inserts.
- Only FIA-approved inserts are permitted in cylinder heads
- Valve seat inserts can be up to 4mm larger than the valve heads themselves
- Seat and guide inserts combined cannot exceed 3% of cylinder head volume
- An additional 1% volume allowance exists for other approved insert types
Official FIA Text
Only FIA-approved Inserts allowed in Cylinder Head: conventional valve seat Inserts up to 4mm larger than valve heads, conventional valve guide Inserts, and spark plug coaxial insert. Total volume of seat and guide Inserts not more than 3% of Cylinder Head volume. Additional 1% allowed for other Inserts.
cylinder head insertsvalve seat insertsvalve guide insertsspark plug insertengine regulations
2026 Season Regulations