Reinforced inlet valves CITROËN Xsara VTS ZX XU10J4RS

CITROËN engines covered

The XU10J4RS is PSA's 2.0 litre (1,998 cc) four-cylinder with 16 valves, bore and stroke both 86 mm. At Citroën it is fitted to the Xsara (N0) 2.0 16V, VTS and 2.0 i 16V from 1998 to 2005, and to the ZX (N2) 2.0 16V from 1996 to 1997, with 163 to 167 hp.

Its cylinder head carries 8 inlet valves, two per cylinder, with a 6 mm stem and an overall length of 106.5 mm. A sharper camshaft, a higher rev limit or a track build makes them work far harder than in standard use.

SUPERTECH and CATCAMS reinforced inlet valves

On every cycle the inlet valve opens to let fresh air in, drops back onto its seat and slides in its guide, dozens of times per second at high rpm. It runs between 400 and 550 °C, a range in which the original chrome-silicon steel falls from 500 MPa at 500 °C to 250 MPa at 600 °C: it loses 50 % of its strength.

The SUPERTECH PEIVN-28692-8 is made of stainless steel with a black nitride treatment: the surface is harder and the stem wears less in the guide. Its stem is undercut below the head, which saves weight and frees the gas path, and the back of the head is cut to ease the air flow towards the seat.

The SUPERTECH comes in standard size, with a 34.1 mm head and a 5.97 mm stem; the CATCAMS 9249001M has a 34 mm head and a 6 mm stem. Both are 106.5 mm long.

Inlet valve technical specification

Fitting details

Before assembly, check that the collets match the groove of the chosen valves.

Technical guide

The brands offered

	Based in San Jose, California, SUPERTECH Performance has been designing valves, springs, retainers and guides for racing for more than thirty years. Every batch goes through ultrasonic, X-ray and laser inspection before reaching engine builders, from drag racing to circuit.
	CATCAMS designs and manufactures racing camshafts in Europe, and offers the valvetrain parts that go with them: valves, springs and retainers, for engines built for rallying as well as for the track.

How to choose

The groove is the recess cut at the end of the stem, where the collets hold the upper retainer. The two sets differ in their dimensions and finish:

When reinforced valves become necessary

• Sharper camshaft or stiffer springs
• Higher rev limit
• Turbocharger or supercharger fitted
• Cylinder head rebuilt for rallying, hillclimb or circuit
• Worn original valves or seats already reground

Compatible vehicles

Related products

For a rebuilt Xsara VTS or ZX 16V cylinder head, the reinforced exhaust valves are on this page: