Reinforced inlet valves TOYOTA Supra 2JZ-GE 2JZ-GTE

TOYOTA engines covered

The 2JZ is Toyota's 3 litre 24-valve inline six: naturally aspirated 2JZ-GE from 214 to 231 hp, twin-turbo 2JZ-GTE from 279 to 330 hp. It powers the Supra A80 from 1993 to 2002, as well as the Aristo, Crown, Chaser, Cresta, Mark II, Soarer, Altezza, Progres and Origin.

The engine takes 12 Toyota 13711-46021 or 13711-46022 inlet valves (13711-46030 on the 1993 to 2005 2JZ-GE), with a 5.97 mm stem, held by 90913-03025 collets. Higher boost, sharper camshafts 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 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 surface harder and smoother: the stem rubs and wears less in the guide.

SUPERTECH also offers a +1 mm oversize: 34.5 mm head instead of 33.5 mm, with the 5.98 mm stem and 98.55 mm length unchanged. 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 34.5 mm, workshop work to plan with the cylinder head rebuild.

The 2JZ sets its valve clearance with shims on solid tappets: after replacing the valves, check the clearance and adjust the shims.

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): 13711-46021 / 13711-46022; 13711-46030 (2JZ-GE, 1993-2005)

Related products

For a rebuilt 2JZ-GE or 2JZ-GTE cylinder head, the reinforced exhaust valves are on this page: