Reinforced exhaust valves Toyota Supra 2JZ-GE 2JZ-GTE

Toyota engines covered

A 3 litre, 24-valve straight six, the 2JZ comes as the naturally aspirated 2JZ-GE and the twin-turbo 2JZ-GTE; the A80 Supra made it a tuning benchmark, and it also powers the Aristo, Chaser, Cresta, Crown, Mark II, Soarer, Altezza, Origin and Progres.

Toyota fits 12 exhaust valves 13715-46020, with a 29 mm head, a 5.97 mm stem and a 99.1 mm overall length. They take the hottest gases, all the more so when raised boost keeps them at high temperature for longer.

SUPERTECH and FERREA reinforced exhaust valves

On a turbocharged engine, the exhaust valve head goes beyond 1,000 °C metal temperature, against 760 to 870 °C naturally aspirated. It cools mainly through its seat, which removes about 75 % of the heat, and through its guide, about 20 %. An EV8 family steel keeps 550 MPa at 600 °C but drops to 300 MPa at 800 °C: the head fatigues, cups and no longer seals cleanly.

FERREA offers its 6000 series in special alloy and its Super Alloy, a nickel-based alloy, each at standard size and +1 mm. SUPERTECH adds black nitrided stainless steel, Inconel, a nickel-based superalloy that keeps 860 MPa at 730 °C and 554 MPa at 815 °C, about 85 % more than the reference steel near 800 °C, and a Nimonic version with a sodium filled stem, which carries heat from the head down the stem.

The +1 mm oversize takes the head to 30 mm with the same stem and length: burnt gases leave the cylinder faster, with a quoted gain of 10 to 12 cfm per millimetre of head, and the 12 exhaust seats are machined to the new diameter.

Exhaust valve technical specifications

The F6099, F1499P and TEVI-1014 are standard size; the F6097, F1497P, TEVN-1016, TEVI-1016 and TEVI-1016-HS are +1 mm. FERREA valves have a 5.98 mm stem, SUPERTECH valves 5.97 mm.

Valve fitting

When refitting the springs, check that the collets match the groove of the chosen part number.

With a 29 mm head the exhaust seats keep their factory size; with 30 mm the workshop machines the 12 seats to the new size.

Once the valves are in, the exhaust clearance is checked cold, 0.25 to 0.35 mm from the factory, and corrected with the shims of the solid tappets.

Technical guide

Our brands

	SUPERTECH Performance has made competition valves in California for more than thirty years. For the 2JZ it offers its exhaust valve in Inconel at standard size, then at +1 mm in black nitrided stainless steel, Inconel and sodium filled Nimonic.
	FERREA, founded in 1978, makes its valves in Florida and Argentina. On the 2JZ it offers its 6000 series and its Super Alloy, each at standard size and +1 mm.

How to choose

Two criteria separate the eight versions, size and material:

When reinforced valves become necessary

• Raised boost or single turbo conversion
• Turbo conversion of a 2JZ-GE (Inconel or Super Alloy version recommended)
• Higher lift camshafts
• Drift, track or drag racing
• Cylinder head rebuild with marked exhaust valves

Vehicle compatibility

OEM part number (exhaust valve): 13715-46020

Don't forget the inlet valves

A 2JZ cylinder head on the bench is the moment to renew the inlet valves and the valve stem seals as well.