Reinforced inlet valves NISSAN VQ35DE VQ40DE

NISSAN engines covered

The VQ35DE is Nissan's 3.5 litre 24-valve petrol V6 with twin overhead camshafts per bank, from 220 to 305 hp depending on version. It powers the 350Z, Skyline V35, Maxima, Altima, Teana, Murano, Pathfinder, Elgrand and Quest among others; the 4.0 litre VQ40DE from the same family drives the Pathfinder III, Xterra, Navara and Patrol VI.

The VQ35DE has 12 Nissan 13201-4W000 inlet valves, then 13201-4W001 from December 2002, with a 37.0 to 37.3 mm head, a 5.965 to 5.980 mm stem and a 96.46 mm length, held by 13210-53Y00 collets; the VQ40DE takes 13201-7S000 then 13201-9FP0A valves, to the same dimensions. A supercharger, a turbo or sharper camshafts load them well beyond stock use.

SUPERTECH and FERREA reinforced inlet valves

Twelve times per crankshaft turn, an inlet valve of the V6 opens to let fresh air in, drops back onto its seat and slides in its guide. It runs between 400 and 550 °C, where the original chrome-silicon steel falls from 500 MPa at 500 °C to 250 MPa at 600 °C: it loses 50 % of its strength.

The SUPERTECH valves are made from a racing stainless steel of the EV8 family, which keeps 650 MPa at 500 °C and 550 MPa at 600 °C, 30 % and then 120 % more than the original steel, and black nitrided for a harder, smoother stem in the guide. The FERREA 6000 series valves have a stem reduced by 0.5 mm at the groove, so the original collets and retainers can be kept.

Both brands offer the standard size (37.15 mm head) and the +1 mm oversize (38.15 mm head), with a 96.60 mm length at SUPERTECH and 96.70 mm at FERREA. On the +1 mm size, the wider head opens a larger passage at the seat: the cylinder fills better and the engine gains power, with the inlet seats cut to the new size.

Inlet valve technical specification

NIVN-1025-12 and NIVN-1028-12: dish head, undercut stem under the head and back cut.

F6019*12 and F6020*12: stem reduced by 0.5 mm at the groove to keep the original collets and retainers; FERREA lists them for the 2003 to 2008 350Z VQ35.

VQ40DE: SUPERTECH part numbers only.

Fitting details

The +1 mm size requires the inlet seats to be cut to 38.15 mm, workshop work to plan with the cylinder head rebuild.

The VQ35DE and VQ40DE set valve clearance with calibrated solid tappets: after replacing the valves, check the clearance and replace the tappets as needed.

Technical guide

Our brands

	SUPERTECH works out of San Jose, California, and has supplied valvetrain parts for racing engines for more than 30 years: valves, springs, retainers and guides. Each part number starts from a specific cylinder head, goes through ultrasound, X-ray and laser checks, then is proven with engine builders, from drag strip to circuit.
	FERREA Racing Components, founded in 1978 in Fort Lauderdale, Florida, by two engine builders from Argentina, forges its valves in one piece from bar stock and then machines them on CNC equipment. Its valves run in NASCAR and dragster engines.

How to choose

The size is chosen according to the condition of the inlet seats and the filling gain wanted.

When reinforced valves become necessary

• Higher-lift camshafts or stiffer springs
• Raised rev limit
• Turbo or supercharger fitted
• Cylinder head rebuilt for circuit, hill climb or rally
• Original valves marked, worn or already reground

Compatible vehicles

OEM part number (inlet valve): 13201-4W000 ; 13201-4W001 (VQ35DE) ; 13201-7S000 ; 13201-9FP0A (VQ40DE)

Related products

For the same VQ35DE cylinder heads, the reinforced exhaust valves are on this page: