Ford Sierra Cosworth YB Turbo +1mm Inlet Valve Set (8)
YB +1mm Cosworth Turbo Inlet Valves.
Largest turbo valve that will go in standard seat.
- Length: 106mm
- Head: 36mm
- Stem: 7mm
- 214N SS Black Nitrided
This is a hardening treatment that even though it is not widely used as the chrome coating, it has several benefits and is becoming very popular, mainly for European and Japanese applications.
The microhardness is higher than the stainless steel base material, keeping good ductility beneath the hard nitrided layer (microhardness is 800HV minimum). Surface finish is smoother than with chromed stems, having less friction between stem and guide.
Valve seat surface is harder with the nitrided layer, lasting longer with lead free fuels, alcohols, nitro or other "explosive" mixes. Matches any kind of seats (nodular iron seats, steel powder metal seats, hard aluminum-copper seats or beryllium copper seats).