Reinforced exhaust valves Opel Z22SE

Opel engines covered

The Z22SE is the Opel 2.2 litre, 16-valve twin-cam four of the Ecotec family, fitted from 2000 to 2008 to the Astra G, Vectra B and C, Zafira A and the Speedster.

It has 8 exhaust valves, two per cylinder. The reinforced valves have a 5.96 mm stem, with a 30.1 mm head at standard size, 30.6 mm at +0.5 mm or 31.1 mm at +1 mm.

FERREA and SUPERTECH reinforced exhaust valves

In the Z22SE, each exhaust valve opening releases a jet of very hot combustion gases into the manifold. Naturally aspirated from the factory, this 2.2 litre takes its valve heads to 760 to 870 °C, a value measured in the metal; grafting on a supercharger or turbo pushes it beyond 1,000 °C. The heat built up leaves the valve mostly through the seat, around 75 %, and about 20 % through the guide. Using EV8 steel as the basis for comparison, strength falls from 550 MPa at 600 °C to 300 MPa near 800 °C. As load and rpm increase, the head heats up, distorts, loses its strength and lets gases leak.

On this engine the two brands take different routes. FERREA supplies Competition Plus stainless valves whose chromed stem is hardened, a stem that resists wear in the guide; the brand credits it with better hot strength, of the order of 20 %, and a seat that wears less, with life extended by 25 %. SUPERTECH relies on Inconel, a superalloy whose base is nickel: it retains 860 MPa at 732 °C and 554 MPa at 816 °C, placing it around 85 % above EV8 steel at 800 °C, and making it the reference to choose as soon as forced induction comes into play.

Two references go beyond the 30.1 mm standard size. The FERREA F1962P grows to 31.1 mm, i.e. +1 mm, and the SUPERTECH GEVI-0012S to 30.6 mm, i.e. +0.5 mm. The 5.96 mm stem stays the same; only the head grows, which eases the exit of burnt gases, improves the following fill and supports power. The 8 seats are machined to the chosen diameter.

Exhaust valve technical specifications

F1961P is standard size, F1962P +1 mm and GEVI-0012S +0.5 mm; all have a 5.96 mm stem, the FERREA a 101.5 mm length and the SUPERTECH 101.3 mm.

Valve fitting

When refitting the springs, check that the collets seat in the groove of the valves and replace any that are worn.

F1961P goes back on seats recut at standard size; F1962P requires the 8 seats to be machined to 31.1 mm; GEVI-0012S requires the seats to be machined to 30.6 mm.

The 8 valves of one engine are fitted at the same size.

Technical guide

Our brands

	Emerging from Silicon Valley more than thirty years ago, SUPERTECH has made its name in racing valvetrain. It produces valves sized for each engine, whether stainless, titanium or Inconel, refined with the help of drag, rally and circuit teams who push them to their limits in competition.
	FERREA Racing Components started out in 1978 with Horacio Ferrea and his partner Daniel Urrutia. The company makes its valves in Florida and Argentina, in stainless, nickel superalloy or titanium, for engine builders of every background, from oval racing to the drag strip.

How to choose

The three references differ first by head size, which sets how much work the seats need, then by material, which should suit the power target of the build and any supercharger or turbo that may be added later.

When reinforced valves become necessary

• More aggressive camshaft profiles or firmer valve springs
• Supercharger or turbo added (Inconel version advised)
• Higher maximum engine speed than standard
• Circuit, slalom or hillclimb use
• Factory exhaust valves found burnt, pitted or warped after high mileage

Vehicle compatibility

OEM part number (exhaust valve):

Don't forget the inlet valves

A Z22SE cylinder head that comes off deserves new parts throughout: plan the inlet valves and valve stem seals too during the same rebuild. The matching page: