Reinforced exhaust valves Nissan 350Z Murano Pathfinder VQ35

Nissan engines covered

The VQ35 is Nissan's 3.5 litre V6 with twin camshafts per bank and 24 valves. It powers the 350Z from 2003 to 2008, the Murano II, the Pathfinder II and IV and the Teana III.

Its two cylinder heads carry 12 exhaust valves. Nissan lists them as 13202-8J100 or 13202-8J110 on the VQ35DE and 13202-JK21A on the VQ35HR, held by 13210-53Y00 collets; FERREA reproduces them with a 31.35 mm head, a 5.96 mm stem and a 94.4 mm overall length. On a V6 that happily revs high, these valves take long periods at high temperature.

SUPERTECH and FERREA reinforced exhaust valves

Twelve times per full cycle, a VQ35 exhaust valve releases gases that have just burnt in the chamber. Its head then lives at 760 to 870 °C, a figure taken in the metal on a naturally aspirated engine like this one; with an added turbo or supercharger it goes past 1,000 °C. That heat flows back roughly 75 % into the cylinder head seat and around 20 % into the guide. EV8 family steel, used here as a yardstick, withstands 550 MPa at 600 °C, but only 300 MPa once 800 °C is reached. Long spells at high rpm, heavy load or added boost eventually tire the head, which distorts and no longer closes cleanly.

To withstand these temperatures, the range brings together several families of metals. FERREA supplies on one hand its 6000 series, made of EV8 stainless and finished with a hard chromed stem, and on the other its Competition Plus range, in special alloy or in nickel based Super Alloy, the latter intended for turbo builds; for the Competition Plus, the maker claims 20 % more strength when hot and a seat that holds 25 % longer. SUPERTECH completes the offer with an Inconel valve, a nickel superalloy that keeps 860 MPa at 732 °C then 554 MPa at 816 °C, about 85 % better than EV8 near 800 °C, the logical choice with forced induction.

In the +1 mm versions, the head diameter goes from 31.35 to 32.35 mm. The exhaust opening is wider, the chamber clears its burnt gases faster and the next charge settles in better, hence a power gain. The 12 seats are then cut to the new dimension.

Exhaust valve technical specifications

Valve fitting

The FERREA valves have a radius groove: check that it matches the 13210-53Y00 collets you reuse before refitting the springs.

At 31.35 mm the seats keep their diameter; with a +1 mm version, the 12 exhaust seats are cut to 32.35 mm.

For valve stem seals, Nissan fits 13207-84A00 or 13207-D4201; the original exhaust valve guide is 13213-31U60.

Technical guide

Our brands

	Californian firm SUPERTECH, a product of Silicon Valley, has spent over thirty years designing complete valvetrains for competition. Each model, whether stainless, titanium or Inconel, targets a given engine and is fine tuned alongside tuners active in drag racing, rallying and circuit racing.
	Since 1978, the year Horacio Ferrea and Daniel Urrutia launched it, FERREA Racing Components has built its valves in workshops in Florida and Argentina. Its output covers stainless steel, nickel superalloys and titanium, serving engine builders on every continent, NASCAR and drag racing included.

How to choose

Every FERREA for this engine shares the same radius groove, so the choice comes down to head size, which may or may not mean recutting the seats, then to the material range, depending on use and whether boost is added.

When reinforced valves become necessary

• Sharper camshafts or uprated valve springs
• Engine often taken beyond its usual rev range
• Turbo or supercharger conversion (Super Alloy or Inconel advised)
• Regular circuit use
• Cylinder head rebuild after marked or pitted exhaust valves

Vehicle compatibility

OEM part number (exhaust valve): 13202-8J100 / 13202-8J110 (VQ35DE), 13202-JK21A (VQ35HR)

Don't forget the inlet valves

Both VQ35 cylinder heads are off? Refresh the inlet side as well, swapping its valves and every stem seal during the very same job. The matching page: