Reinforced exhaust valves Peugeot Citroën EW10J4

Peugeot and Citroën engines covered

The EW10J4, the naturally aspirated 2 litre 16-valve four-cylinder of the PSA group, powered the Peugeot 206 S16, 206 CC and 206 SW, the 307, 406, 407, 607, 806 and 807, as well as the Citroën Xsara, Xsara Picasso, C4, C4 Picasso, C5, C8 and Evasion from 1999 to 2014: 135 hp as the RFR, then 120 to 143 hp as the RFN depending on the model.

It has 8 exhaust valves, two per cylinder, loaded on every cycle by the burnt gases, especially when the engine runs for long periods near the rev limit.

SUPERTECH reinforced exhaust valves

As it opens, the EW10J4 exhaust valve sits right in the stream of burnt gases: on this naturally aspirated engine its head metal ranges from 760 to 870 °C, and would climb beyond 1,000 °C with a turbo. Most of this heat, about 75 %, drains towards the seat, and about 20 % towards the guide. Taken as the yardstick, an EV8 grade withstands 550 MPa at 600 °C but just 300 MPa at 800 °C; from then on the head bends, fatigues and the seal at the seat is lost.

SUPERTECH cuts the PEEVN-28595-8 from Inconel, a nickel superalloy holding 860 MPa at 732 °C and 554 MPa at 816 °C, around 85 % stronger than EV8 near 800 °C: enough to spend long periods near the red line without weakening the head.

Its geometry matches the Peugeot part: 29.0 mm head, a 5.97 mm stem and a 103.35 mm length: the 8 exhaust seats need no machining, a regrind is enough to restore an even contact.

Exhaust valve technical specifications

The set keeps the 29.0 mm head, the 5.97 mm stem and the 103.35 mm length.

Valve fitting

Check the collets on reassembly: they must be in good condition and seat properly in the stem groove.

The 5.97 mm stem slides in the guides: check their clearance and replace the valve stem seals at every rebuild.

Regrind the exhaust seats with the new valves to restore an even contact band.

Technical guide

Our brand

SUPERTECH Performance designs valves, springs, guides and titanium retainers for motorsport in California and has done so for over 30 years. Stainless, titanium or Inconel: the brand defines each valve for a precise engine and tests it with recognised dragster, rally and circuit tuners.

How to choose

On the EW10J4 the range comes down to a single valve: the PEEVN-28595-8, in Inconel, at the original 29.0 mm size. What remains is to check the intended use and the head condition; its seats are simply reground:

When reinforced valves become necessary

• Cams wilder than the factory ones, or stiffer springs
• Engine speed raised after tuning the EW10J4
• Regular circuit driving or hillclimb entries
• Exhaust valves marked, pitted or no longer sealing
• Complete head overhaul on a 206, 307 or C4

Vehicle compatibility

OEM part number (exhaust valve):

Don't forget the inlet valves

With the EW10J4 head off, renew the whole inlet side within that single job, valves included, and do not forget the stem seals. This is the part made for this engine: