Reinforced inlet valves TOYOTA 2AZ-FE

TOYOTA engines covered

The 2AZ-FE is Toyota's 2.4 litre 16-valve twin-cam petrol four, from 143 to 173 hp depending on version. It powers the Camry from 2001 to 2011, the RAV4 II and III, the Previa, Avensis Verso, Highlander, Corolla and Alphard among others.

The engine has 8 Toyota 13711-28010 inlet valves, then 13711-0H010 from 2001, with a 34.0 mm head, a 5.47 mm stem and a 101.71 mm length, held by 90913-03028 collets. Sharper camshafts, a supercharger or a raised rev limit load them well beyond stock use.

SUPERTECH reinforced inlet valves

At every turn of the cam, the inlet valve opens under the push of the tappet, comes back to strike its seat and slides in its guide, dozens of times per second at high revs. It runs between 400 and 550 °C, where the original chrome-silicon steel drops from 500 MPa at 500 °C to 250 MPa at 600 °C: 50 % of its strength is gone.

SUPERTECH valves are made from EV8 racing stainless steel, which keeps 650 MPa at 500 °C and 550 MPa at 600 °C, 30 % and then 120 % more than the original steel. The 35.0 mm version also gets a chrome coating.

SUPERTECH offers them in standard size (34.0 mm head) and in +1 mm oversize (35.0 mm head), with a 5.48 mm stem and a 101.85 mm length. On the +1 mm size, the wider head opens a larger passage at the seat, the cylinder fills better and the engine gains power, with the inlet seats cut to the new size.

Inlet valve technical specification

Fitting details

The +1 mm size requires the inlet seats to be cut to 35.0 mm, workshop work to plan with the cylinder head rebuild.

The 2AZ-FE sets its valve clearance with solid tappets of graded thickness: after replacing the valves, check the clearance and change the tappets as needed.

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.

How to choose

The size is chosen according to the condition of the inlet seats and the filling gain wanted.

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

OEM part number (inlet valve): 13711-28010; 13711-0H010 (from 2001)