Reinforced inlet valves SEAT 1.8 T 20V

The SEAT engines covered

At SEAT, the 1.8 T 20V is the Volkswagen group's 1,781 cc turbocharged four-cylinder with five valves per cylinder: three inlet, two exhaust. From 1997 to 2010 it powers the Leon and Leon Cupra R, Ibiza Cupra and FR, Cordoba Cupra, Toledo and Alhambra, from 150 to 225 hp.

The engine has 12 original 058 109 601 C inlet valves: 26.9 mm head, 6 mm stem, 105.1 mm length. A remap, a bigger turbo or sharper camshafts put far greater loads on them than stock use.

SUPERTECH and FERREA reinforced inlet valves

At high revs, each 1.8 T inlet valve lifts and lands back on its seat dozens of times a second, its stem sliding constantly in the guide, at 400 to 550 °C. In that range the original chrome-silicon steel drops from 500 MPa at 500 °C to 250 MPa at 600 °C: half of its strength, 50 %, is gone.

The SUPERTECH valves are black nitride stainless steel: the treatment hardens and smooths the surface, limiting stem wear in the guide. The FERREA F1556P and F1557P belong to the Competition Plus series, for which the manufacturer claims 20 % more hot strength and fatigue resistance, and 25 % longer seat life.

In the +1 mm size the head grows from 26.9 to 27.9 mm, with stem and length unchanged: the airway widens, the cylinder fills better and the engine gains power. The inlet seats are then cut to the new size.

Inlet valve technical specification

AIVN-1103S-12 and AIVN-1106S-12: to be fitted with SUPERTECH KPR-6S/7 collets.

Fitting details

SUPERTECH requires its KPR-6S/7 collets with the 1-groove AIVN-1103S-12 and AIVN-1106S-12 valves. The 3-groove valves, AIVN-1103-12 and FERREA, keep original-type collets.

The +1 mm size (F1557P*12, AIVN-1106S-12) needs inlet seats cut to 27.9 mm.

These engines use hydraulic tappets: there is no valve clearance to set after the replacement.

Technical guide

Our brands

	SUPERTECH has been making racing valvetrain parts in San Jose, California, for more than thirty years. Each valve follows the design of a specific cylinder head, goes through ultrasonic, X-ray and laser checks, then runs in its partners' engines on circuits and drag strips.
	FERREA Racing Components, founded in 1978 in Fort Lauderdale, Florida, by two engine builders from Argentina, forges its valves in one piece from bar stock and then machines them on CNC equipment. Its valves run in NASCAR and dragster engines.

How to choose

The groove is the notch in the stem where the collets that hold the valve sit.

When reinforced valves become necessary

• Higher-lift camshafts or firmer springs
• Raised rev limit
• Fitting a supercharger or turbocharger
• Cylinder head rebuilt for circuit, drift or rally use
• Original valves marked, worn or already reground

Compatible vehicles

OEM part number (inlet valve): 058 109 601 C

Related products

A rebuilt 1.8 T cylinder head also gets new valve stem seals. The part for this engine: