Reinforced inlet valves NISSAN SR20DE SR20DET

NISSAN engines covered

The SR20 is Nissan's 2-litre four-cylinder with 16 valves and twin overhead camshafts. As the naturally aspirated SR20DE it powered the 100NX and Sunny GTI, the Almera GTi, the Primera and the Serena in the 1990s; as the turbocharged SR20DET it drove the Sunny GTi-R and the 200SX S14 and S15.

It has 8 inlet valves, part numbers 13201-53J00 then 13201-1E700, 13201-1E710 and 13201-1E711, with a 34.0 mm head, a 6 mm stem and a length of 101.4 to 101.5 mm. Raised boost, sharper camshafts or more rpm put them under heavy load.

SUPERTECH and FERREA reinforced inlet valves

Running flat out, the inlet valve opens and shuts the fresh-air path dozens of times each second. It hammers onto the cylinder head seat as it closes, while its stem shuttles up and down in the guide. Between 400 and 550 °C, its working band, the stock chrome-silicon steel has already begun to lose strength: 500 MPa at 500 °C, then 250 MPa at 600 °C, one step higher, a drop of 50%. Extra lift, stiffer springs, more revs or more boost multiply these blows, this rubbing and this heat.

The reinforced versions are made from a competition chrome-nickel stainless steel related to EV8 (21-4N): at 500 °C it holds 650 MPa, 30% above the stock steel, and at 600 °C still 550 MPa, 120% above it. The FERREA valve belongs to the Competition Plus line, which its maker rates at 20% more resistance to heat and fatigue, with seats lasting 25% longer. Two finishes are therefore on offer for the SR20: SUPERTECH stainless with a black nitride treatment, whose hardened layer glides better and wears less, and the FERREA chrome stem.

Each brand also comes in +1 mm: the head grows from 34.15 to 35.15 mm, with stem and length left alone. The airway at the seat opens up, the cylinders breathe better and the engine makes more power, as long as the head's seats are machined to that size.

Inlet valve technical specifications

Valve fitting

The collets must seat properly in the groove of the new valves: FERREA pairs its SR20 valves with K10036 collets.

The +1 mm size calls for the 8 inlet seats to be machined to the new head diameter, 35.15 mm.

Technical guide

Our brands

	SUPERTECH has worked out of San Jose, California, for over three decades, producing valvetrain components for motorsport. Its valves are drawn up engine by engine, inspected by ultrasound, radiography and laser, then refined with tuners, from road course to quarter mile.
	FERREA Racing Components dates from 1978, set up by two Argentinian engine men in Fort Lauderdale, Florida, and keeps all of its manufacturing in house. Its one-piece valves start from forged steel bar, are wholly machined on CNC equipment and line up in NASCAR, at drag strips and on circuits.

How to choose

Below the retainer, a pair of collets grips the groove cut in the stem and holds the valve. On the SR20 you pick the head diameter first, then the stem finish.

When reinforced valves become necessary

• Camshafts with more lift, or uprated valve springs
• Higher rev limit
• Larger turbo or increased boost pressure
• Cylinder head prepared for circuit, drift or rally use
• Original valves pitted, worn or at repair size

Vehicle compatibility

OEM part number (inlet valve): 13201-53J00 ; 13201-1E700 ; 13201-1E710 ; 13201-1E711

Related products

With the head off, inlet valves, exhaust valves and their stem seals are normally all replaced in one go. The SR20DE exhaust valves are available here: