Reinforced exhaust valves Nissan Bluebird SR20VE

Nissan engines covered

The SR20VE is the NEO VVL variable lift version of Nissan's 2 litre SR20 four, with 16 valves and twin overhead camshafts. This page covers its first generation, known as P11, with 6 mm valve stems, fitted in particular to the Bluebird U14 from 1997.

Its 8 exhaust valves, two per cylinder, carry the original part number 13202-1N500. Switching to high lift at high rpm exposes them for long periods to very hot burnt gases.

SUPERTECH reinforced exhaust valves

On the SR20VE P11, every exhaust valve lets through the gases leaving the chamber: its head climbs to 760 to 870 °C naturally aspirated, and past 1,000 °C once forced induction is grafted on. Close to 75 % of this heat flow drains through the seat and close to 20 % through the guide. EV8-type steel, taken as the benchmark for the factory part, offers 550 MPa at 600 °C but only 300 MPa at 800 °C; any hotter and the head overheats, tires, warps and no longer closes tightly.

Both SUPERTECH versions are cut from Inconel, a nickel-rich superalloy that holds 860 MPa at 730 °C and still 554 MPa near 815 °C. Against EV8, the lead reaches about 85 % around 800 °C, which makes it the material to pick as soon as a turbo enters the project.

The +2 mm version widens the head from 29.15 to 31.15 mm while leaving the 5.97 mm stem and the 100.5 mm length untouched. Each extra millimetre frees roughly 10 to 12 cfm: the chamber empties faster and takes in the fresh charge better; all 8 seats must then be cut to this diameter.

Exhaust valve technical specifications

NEVI-1004-VE: 29.15 mm head (standard); NEVI-1007-VE: 31.15 mm head (+2 mm); 5.97 mm stem and 100.5 mm length for both.

Valve fitting

On reassembly, the 6 mm collets must seat properly in the groove of the new valves; the KPR-6N-6-ST collets are intended for this engine.

At 29.15 mm, recutting the seats is enough; at 31.15 mm, the 8 exhaust seats are machined.

Fit all 8 valves at the same size and install new exhaust valve stem seals, such as VS-N6E-8.

Technical guide

Our brand

SUPERTECH Performance, based in California, has designed valves, springs, retainers and guides intended for competition for more than 30 years. Each valve, in stainless steel, titanium or Inconel, is engineered for one specific engine and proven with dragster, rally and track tuners.

How to choose

On the SR20VE P11, a single material is offered, Inconel, and the 5.97 mm stem stays that of the factory part. The choice is the head diameter, set by how worn the seats are and the machining planned on the head:

When reinforced valves become necessary

• Turbo or supercharger fitted to the SR20VE (Inconel version advised)
• Sharper camshafts or uprated springs
• Rev limiter pushed higher by a new engine map
• Cylinder head rebuilt for circuit, rally or drift use
• Factory valves burnt, pitted or tired

Vehicle compatibility

OEM part number (exhaust valve): 13202-1N500

Don't forget the inlet valves

Once the SR20VE cylinder head is off, make the most of it to renew the inlet side together with the exhaust valve stem seals. The parts designed for this engine: