Reinforced inlet valves SUPERTECH NISSAN VK56DE

NISSAN engines covered

The VK56DE is Nissan's V8 of 5.6 litres with 32 valves and twin overhead camshafts per bank. From 2003 it powers the Armada TA60, the Titan A60, the Pathfinder R51 and the Patrol Y62, with 309 to 360 hp.

It has 16 inlet valves, two per cylinder, with an original stem of 5.965 to 5.980 mm (Nissan part number 13201-7S000, then 13201-9FP0A from 2013). A supercharger, a sharper camshaft or more revs load them far beyond standard use.

SUPERTECH reinforced inlet valves

On every cycle the inlet valve opens to let air in, drops back onto its seat and slides in its guide. It works between 400 and 550 °C; a common chrome-silicon steel goes there from 500 MPa at 500 °C to 250 MPa at 600 °C, 50 % less strength.

SUPERTECH's NIVN-1028-16 is made of black nitride stainless steel, with an undercut stem under the head, a back cut and a dished head; nitriding hardens the surface and limits stem wear in the guide.

It is listed at +1 mm oversize, with a 38.15 mm head, a 5.96 mm stem and a length of 96.6 mm: the passage at the seat widens and the cylinder fills better, provided the 16 inlet seats are cut to this diameter.

Inlet valve technical specification

NIVN-1028-16: undercut stem, back cut, dished head; set of 16 valves.

Fitting details

The +1 mm oversize requires inlet seats cut to 38.15 mm before fitting.

The VK56DE has calibrated mechanical tappets: after replacing the valves, check the clearance and change tappets where needed.

Technical guide

The brand offered

SUPERTECH Performance has been making valvetrain parts for racing engines in California for more than 30 years: valves, springs and retainers. Its series go through ultrasound, X-ray and laser checks, then are developed with engine builders.

How to choose

A single part number is offered for this engine:

When reinforced valves become necessary

• Supercharger or turbo added to the V8
• Sharper camshafts or firmer springs
• Raised maximum rpm
• Cylinder heads rebuilt for engine tuning
• Original valves worn or seats already reground

Compatible vehicles

OEM part number (inlet valve): 13201-7S000 (2003-2013), 13201-9FP0A (since 2013)