Reinforced inlet valves PEUGEOT CITROËN 106 S16 Saxo TU5J4

PEUGEOT and CITROËN engines covered

The TU5J4 is PSA's 1.6 litre, 16-valve, twin-cam four-cylinder that powers the Peugeot 106 S16, from 1996 to 2004, in 118 and 120 hp versions. Under the bonnet of the Citroën Saxo, the TU5J4 is PSA's 1.6 litre, 16-valve, twin-cam four-cylinder: it powers the 120 hp Saxo 1.6, from 1996 to 2004, and the 118 hp Saxo 1.6 VTS, from 1996 to 2003.

Its cylinder head carries 8 inlet valves, two per cylinder. Sharper camshafts, stiffer springs or a higher rev limit for competition expose them to more heat and harder seat impacts.

SUPERTECH, FERREA and CATCAMS reinforced inlet valves

In the TU5J4, each cam in turn opens one of the 8 inlet valves: the fresh mixture rushes into the cylinder, then the valve comes back to tap its seat while its stem slides in the guide, and this movement exceeds twenty strokes a second when the 1.6 litre nears its red line. The valve then takes between 400 and 550 °C. Yet the chrome-silicon steel of an ordinary valve, which holds 500 MPa at 500 °C, falls to 250 MPa from 600 °C: 50 % of its strength vanishes just above its working range.

The two FERREA Series 6000 valves and the SUPERTECH PEIVN-29368-8 are made from EV8 stainless steel, which keeps 550 MPa at 600 °C, 120 % more than chrome-silicon at that same temperature; at FERREA, this series teams EV8 with a hard-chromed stem. The SUPERTECH PEIVN-28065-8 is stainless steel. Both SUPERTECH parts finally receive black nitriding, a hardened layer that shields the stem and slows wear against the guide, even when the engine stays high in the revs for long minutes on a special stage or a timed hill climb.

To find more air, the PEIVN-29368-8 and F6761*8 carry a 29.75 and 29.8 mm head, against 28.75 and 28.8 mm at standard size, stem and length staying stock. That millimetre widens the gas passage at the seat: the cylinders breathe more and the TU5J4 gains power, provided the 8 inlet seats of the head are machined to this new diameter first.

Inlet valve technical specification

Fitting details

The 29.75 and 29.8 mm valves need inlet seats machined to their size; the 28.75 and 28.8 mm ones fit on seats reconditioned to the factory size.

Fit all 8 valves from the same set and replace the inlet valve stem seals at the same time.

Technical guide

The brands offered

	FERREA Racing Components took root in 1978 in Fort Lauderdale, Florida, around two engine builders from Argentina. Each valve starts there as one-piece forged bar stock, then takes shape on numerical machines before joining NASCAR grids or drag strips.
	SUPERTECH Performance, working out of San Jose in California, has turned out valve train parts for motorsport for three decades and more. Its valves are forged first and then finished on CNC; each batch goes under ultrasound, X-rays and laser before shipping.
	CATCAMS, an engine specialist set up in Belgium, made its name with camshafts and also offers springs, tappets and valves. Each of its profiles is drawn for one defined engine and one use, from the everyday road car up to a full build for rally stages.

How to choose

The groove is the notch cut near the stem tip, where the collets sit to retain the retainer. On the TU5J4, you choose the size first, then the material:

When reinforced valves become necessary

• Pointier camshafts or springs rated higher
• Rev limit pushed past stock
• Supercharger or turbo added on this 1.6 litre
• Engine entered in rallies, hill climbs or track
• Pitted or worn-out stock valves, or reground seats

Compatible vehicles

Related products

Is your TU5J4 head on the bench? Use the moment to replace its 8 exhaust valves too, whose reinforced version we stock, on the page below: