Reinforced inlet valves TOYOTA 1ZZ-FE

TOYOTA engines covered

The 1ZZ-FE is Toyota's 1.8 litre 16-valve four-cylinder with twin overhead camshafts, from 121 to 143 hp. It is found in the Corolla E11, E12 and E15, the Corolla Verso, the Avensis T22 and T25, the Celica T23, the MR2 III, the RAV4 II, the Matrix and many Japanese market models, from 1997 to 2014.

Its cylinder head carries 8 inlet valves: the 13711-22030 with a 32.0 mm head on the first engines, then the 13711-22040 and 13711-0D020 with a 31.0 mm head, all with a 5.470 to 5.485 mm stem held by 90913-03028 or 90080-38115 collets. Sharper camshafts, a supercharger or a higher rev limit expose them to more heat and harder impacts than everyday use.

SUPERTECH reinforced inlet valves

On the inlet side, the valve lets fresh air in, drops back onto its seat every cycle and slides constantly in its guide, between 400 and 550 °C. At these temperatures, the chrome-silicon steel of ordinary valves goes from 500 MPa at 500 °C to 250 MPa at 600 °C: it loses 50 % of its strength.

SUPERTECH's TIVN-1021-8 is made of black nitride stainless steel: nitriding makes the stem harder and smoother, so it rubs and wears less in the guide. The stem is undercut below the head and the head is back cut, two machining steps that open up the airflow path.

With its 32 mm head, it is 1 mm larger than the 31.0 mm valve of engines built with the 13711-22040 or 13711-0D020: the flow area grows and the cylinder fills better, once the inlet seats are cut to this diameter. On engines built with the 32 mm valve (13711-22030), this part is at the standard size.

Inlet valve technical specification

Fitting details

On engines originally fitted with the 31.0 mm valve, the inlet seats must be cut to the diameter of the 32 mm head.

Valve clearance is set with calibrated tappets (0.15 to 0.25 mm cold on the inlet side): after replacing the valves, check it and change the tappets if needed.

Technical guide

The brand offered

Based in California, SUPERTECH Performance has designed valvetrain parts for racing for more than thirty years: valves, springs, retainers and guides, each checked by ultrasound, X-ray and laser before reaching engine builders.

When reinforced valves become necessary

• Higher lift camshafts or stiffer springs
• Raised rev limit
• Supercharger or turbo fitted
• Cylinder head rebuilt for track, hill climb or rally
• Worn original valves or seats already reground

Compatible vehicles

OEM part number (inlet valve): 13711-22030 (32.0 mm); 13711-22040 / 13711-0D020 (31.0 mm)

Related products

With the 1ZZ-FE cylinder head off, also replace its 8 exhaust valves: