Reinforced exhaust valves Toyota Celica MR2 3S-GTE

Toyota engines covered

The 3S-GTE is Toyota's 2 litre 16-valve turbocharged four, used in the ST165, ST185 and ST205 Celica GT-Four, the SW20 MR2 Turbo and the four-wheel-drive Caldina.

Its 8 exhaust valves have a 29 mm standard head, a 5.97 mm stem and a 99.7 mm overall length; they work in the gases that feed the turbo, hotter still when boost is raised.

SUPERTECH and FERREA reinforced exhaust valves

Under boost, the metal of the exhaust head goes beyond 1,000 °C, against 760 to 870 °C naturally aspirated. The seat removes about 75 % of the heat and the guide about 20 %. An EV8 family steel is the benchmark: 550 MPa at 600 °C, 300 MPa at 800 °C; beyond that, the head fatigues, distorts and leaks.

FERREA offers two materials: its Super Alloy, a nickel-based alloy, and its 6000 series in special alloy, each at standard size and +1 mm. SUPERTECH offers black nitrided stainless steel, whose hardened surface resists wear in the guide, at +0.5 and +1 mm, and Inconel at +1 mm, a nickel-based superalloy that keeps 554 MPa at 815 °C, about 85 % more than the reference steel near 800 °C.

With 29.5 mm (+0.5 mm, SUPERTECH) or 30 mm (+1 mm, FERREA and SUPERTECH), the head grows: burnt gases leave faster, with a quoted gain of 10 to 12 cfm per millimetre of head, and the 8 exhaust seats are machined to the new diameter.

Exhaust valve technical specifications

The F1865P and F6065 are standard size, the F1866P, F6066, TEVN-1016 and TEVI-1016 +1 mm; the TEVN-1011 is +0.5 mm, in black nitrided stainless steel.

Valve fitting

Before refitting the springs, check that the collets suit the groove of the chosen valve.

At 29 mm the seats stay as they are; with a 29.5 or 30 mm head, the 8 exhaust seats are machined to the new size.

All part numbers keep the 5.97 mm stem; length goes from 99.7 mm (FERREA) to 99.5 mm (TEVN-1011) and 99.1 mm (TEVN-1016, TEVI-1016).

Technical guide

Our brands

	SUPERTECH Performance, a Californian maker of competition valves for more than thirty years, offers the 3S-GTE exhaust valves in black nitrided stainless steel at +0.5 and +1 mm, and in Inconel at +1 mm.
	FERREA, founded in 1978, makes its valves in Florida and Argentina. For the 3S-GTE it offers its Super Alloy and its 6000 series, at standard size and +1 mm.

How to choose

Size and material separate the seven versions:

When reinforced valves become necessary

• Higher boost pressure
• Larger turbo
• More aggressive camshafts
• Rally and track use
• Cylinder head rebuild with worn exhaust valves

Vehicle compatibility

OEM part number (exhaust valve): 13715-88360 (10/1987 à 08/1989) ; 13715-88361 (01/1990 à 06/1995)

Don't forget the inlet valves

An open 3S-GTE cylinder head is the right time to replace the inlet valves and the valve stem seals too.