Reinforced inlet valves TOYOTA 1GR-FE 4.0 V6

TOYOTA engines covered

The 1GR-FE is Toyota's 3,956 cc V6 with 4 valves per cylinder, from 231 to 282 hp depending on version, 306 hp with the supercharger of the Hilux TRD. It powers the Land Cruiser (Prado J12 and J15, 70, 200 and 300 series), the Hilux VII and VIII, the Fortuner, the 4Runner, the FJ Cruiser, the Tacoma and the Tundra, since 2002.

The engine has 12 Toyota 13711-31070 or 13711-31071 inlet valves (13711-31100 or 13711-31101 from 2009 to 2013), with a 5.47 mm stem, held by 90913-03028 collets. Forced induction, 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 offers them in two oversizes with a flat face: +1 mm (37.5 mm head) and +1.5 mm (38.0 mm head), with a 5.47 mm stem and a 107 mm length. 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

TIVN-1052F-12 and TIVN-1053F-12: flat face, undercut stem under the head, back cut, EV8 stainless steel.

Fitting details

The +1 mm and +1.5 mm sizes require the inlet seats to be cut to 37.5 mm or 38.0 mm, workshop work to plan with the cylinder head rebuild.

The 1GR-FE sets its valve clearance with tappets of calibrated thickness: after replacing the valves, check the clearance and change the tappets if 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): 13711-31070 / 13711-31071; 13711-31100 / 13711-31101 (2009-2013)

Related products

When the 1GR-FE cylinder heads are rebuilt, the matching reinforced exhaust valves are offered here: