Reinforced inlet valves SUPERTECH NISSAN VG30DE VG30DET VG30DETT

NISSAN engines covered

The VG30DE is Nissan's 3.0 litre V6 with 24 valves and twin overhead camshafts per bank; the VG30DET and VG30DETT are its turbo and twin-turbo versions. From 1986 to 2001 they powered the 300ZX Z32, the Cedric, Gloria and Cima, the Leopard F31 and the Maxima QX A32 and A33, with 185 to 305 hp.

Each engine has 12 inlet valves, two per cylinder, with an original head of 34.0 to 34.2 mm and a stem of 5.965 to 5.980 mm. Higher boost, a sharper camshaft or more revs load them far beyond standard use.

SUPERTECH and FERREA reinforced inlet valves

The inlet valve opens the way for fresh air, closes back onto its seat on every cycle and slides constantly in its guide. It runs between 400 and 550 °C, a range in which an ordinary chrome-silicon steel drops from 500 MPa at 500 °C to 250 MPa at 600 °C, 50 % less strength.

SUPERTECH's NIVN-1017-12 is made of black nitride stainless steel: nitriding hardens the surface and reduces stem wear in the guide. The FERREA valves are Competition Plus, stainless steel with a chrome stem: the range gains 20 % hot strength and fatigue resistance and extends seat life by 25 %.

It comes in the +0.5 mm oversize, with a 34.5 mm head, a 5.97 mm stem and a length of 103.15 mm: the passage at the seat widens and the cylinder fills better, provided the 12 inlet seats are cut to this diameter. For the VG30DETT of the 300ZX, FERREA supplies the standard size (34 mm head) and the +1 mm oversize (35 mm head), with a 6 mm stem and a length of 103.13 mm.

Inlet valve technical specification

Set of 12 SUPERTECH inlet valves for the Nissan 300ZX VG30D: 34.5 mm head (0.5 mm oversize), 5.97 mm stem, 103.15 mm length, black nitride stainless steel.

F1847P*12 and F1848P*12: for the twin-turbo VG30DETT of the 300ZX Z32.

Fitting details

The +0.5 mm oversize requires inlet seats cut to 34.5 mm before fitting.

The VG30 has hydraulic tappets: there is no valve clearance to set after reassembly.

Technical guide

Our brands

	SUPERTECH Performance, based in California, has designed valves, springs and pistons for racing for more than 30 years. Each series is checked by ultrasound, X-ray and laser before being validated on circuit, drift and drag engines.
	FERREA Racing Components was founded in 1978 in Fort Lauderdale, Florida, by two engine builders from Argentina. Its valves are forged in one piece from bar stock, then fully CNC machined, and run in NASCAR as well as in dragsters.

How to choose

Two brands are offered: the size is chosen according to the condition of the inlet seats and the filling wanted.

When reinforced valves become necessary

• Higher boost on a VG30DETT
• Sharper camshafts or firmer springs
• Raised maximum rpm
• Cylinder head rebuilt for circuit, drift or drag
• Original valves worn or seats already reground

Compatible vehicles

OEM part number (inlet valve): 13201-F6511 (Cima Y32 VG30DET, 1993-1996)