Reinforced inlet valves NISSAN 200SX 180SX CA18DET

NISSAN engines covered

The CA18DET is Nissan's 1.8 litre 16-valve four-cylinder with twin overhead camshafts and a turbo, from 169 to 201 hp depending on version. It powers the 180SX and 200SX S13 coupés from 1988 to 1993, and the Auster T12 1.8 Xtt in Japan.

The engine has 8 inlet valves, two per cylinder. Raised boost, sharper camshafts or a higher rev limit load them well beyond stock use.

SUPERTECH reinforced inlet valves

On a tuned turbo four-cylinder, each inlet valve opens dozens of times per second, then strikes its seat and slides in its guide under boost pressure. It runs between 400 and 550 °C, where the original chrome-silicon steel falls from 500 MPa at 500 °C to 250 MPa at 600 °C: 50 % of its strength is gone.

SUPERTECH makes these valves from a racing stainless steel of the EV8 family, which keeps 650 MPa at 500 °C and 550 MPa at 600 °C, 30 % and then 120 % more than the original steel. Black nitriding makes the stem harder and smoother, so it wears less in the guide.

SUPERTECH supplies it in standard size: 34.15 mm head, 5.97 mm stem and 88.90 mm length. It fits inlet seats still at factory size.

Inlet valve technical specification

Undercut stem under the head and back cut.

Fitting details

Technical guide

The brand offered

SUPERTECH works out of San Jose, California, and has supplied valvetrain parts for racing engines for more than 30 years: valves, springs, retainers and guides. Each part number starts from a specific cylinder head, goes through ultrasound, X-ray and laser checks, then is proven with engine builders, from drag strip to circuit.

When reinforced valves become necessary

• Higher-lift camshafts or stiffer springs
• Raised rev limit
• Turbo or supercharger fitted
• Cylinder head rebuilt for circuit, hill climb or rally
• Original valves marked, worn or already reground

Compatible vehicles

Related products

For a rebuilt CA18DET cylinder head, the reinforced exhaust valves are available here: