Reinforced exhaust valves Toyota Supra Cressida 7M-GE 7M-GTE

Toyota engines covered

The 7M is Toyota's 3 litre twin-cam 24-valve straight six, naturally aspirated (7M-GE) or turbocharged (7M-GTE), found in the A70 Supra, Cressida, Chaser, Cresta and Crown.

It has 12 exhaust valves, two per cylinder, with a 27.5 mm standard head, a 6 mm stem and a 98.2 mm overall length.

SUPERTECH and FERREA reinforced exhaust valves

With the turbo on boost, the head of an exhaust valve passes 1,000 °C, while a naturally aspirated engine stays around 760 to 870 °C. The seat removes about 75 % of it, the guide about 20 %. EV8 family steel, taken as the reference for the original, only offers 300 MPa at 800 °C against 550 MPa at 600 °C: the overheated head fatigues, distorts and lets gas through.

FERREA offers its Super Alloy valve, a nickel-based alloy, at standard size and +1 mm. SUPERTECH offers the TEVI-1007-12 in Inconel, a nickel-based superalloy that keeps 860 MPa at 732 °C and 554 MPa at 816 °C, about 85 % more than EV8 steel around 800 °C, the one to choose on a 7M-GTE running higher boost.

With 28 mm (+0.5 mm, SUPERTECH) or 28.5 mm (+1 mm, FERREA), the head grows: burnt gases leave 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 F1861P is standard size and the F1862P +1 mm, both in Super Alloy, for the 7M-GE and 7M-GTE; the TEVI-1007 is an Inconel racing valve at +0.5 mm for the Supra 7M-GTE.

Valve fitting

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

At 27.5 mm the seats stay as they are; with a 28 or 28.5 mm head, the 12 exhaust seats are machined to the new size before assembly.

All three part numbers keep the 98.2 mm length and a 6 mm stem (5.97 mm for the SUPERTECH).

Technical guide

Our brands

	SUPERTECH Performance, a Californian maker of competition valves for more than thirty years, offers the Supra 7M-GTE an Inconel exhaust valve at +0.5 mm.
	FERREA, founded in 1978, makes its valves in Florida and Argentina. For the 7M-GE and 7M-GTE it offers its Super Alloy valve in standard size and +1 mm.

How to choose

Size and material separate the three versions:

When reinforced valves become necessary

• Higher boost pressure (Inconel version recommended)
• Larger turbo
• More aggressive camshafts
• Track use
• Cylinder head rebuild with worn exhaust valves

Vehicle compatibility

OEM part number (exhaust valve): 13715-42010

Don't forget the inlet valves

An open 7M-GTE cylinder head is also the time to replace the inlet valves and the valve stem seals.