Reinforced exhaust valves Nissan Skyline Laurel RB20DE RB20DET

Nissan engines covered

The RB20 is Nissan's 2.0 litre, 24-valve straight six, offered naturally aspirated (RB20DE) and turbocharged (RB20DET). This page covers the Skyline R31 and R32, the Laurel C33 and C34 and the Cefiro A31.

Its cylinder head carries 12 exhaust valves. On the RB20DET they open into the gases that drive the turbine; a build that raises boost or revs puts them under even more strain.

SUPERTECH reinforced exhaust valves

The metal of an exhaust valve head sits between 760 and 870 °C on a naturally aspirated engine and passes 1,000 °C under boost. About 75 % of the heat leaves through the seat and 20 % through the guide. An EV8 family steel gives the benchmark: 550 MPa at 600 °C, 300 MPa at 800 °C. Beyond that, the head fatigues, distorts and seals poorly.

SUPERTECH makes both valves in Inconel, a nickel-based superalloy that keeps 860 MPa at 732 °C and 554 MPa at 816 °C, around 85 % better than EV8 steel near 800 °C. It is the material to choose as soon as boost goes up.

Both part numbers carry a 27.5 mm head, +1 mm: the flow area grows and the burnt gases leave the chamber sooner, with a quoted gain of 10 to 12 cfm per millimetre of head. The 12 exhaust seats are then machined to that diameter.

Exhaust valve technical specifications

Both valves are +1 mm; the NEVI-1042-SL, 16.8 mm longer with a 7.4 mm stem tip instead of 4.5 mm, is intended for a solid tappet conversion.

Valve fitting

Before refitting the springs, make sure the valve lock groove matches the collets you reuse.

With a 27.5 mm head, the 12 exhaust seats are machined before the valves are fitted.

The NEVI-1042-SL is 16.8 mm longer than the NEVI-1042 and its stem tip goes from 4.5 to 7.4 mm: it only suits a cylinder head converted to solid tappets.

Technical guide

Our brand

SUPERTECH Performance, based in California, has been making competition valves for more than thirty years. For the RB20 it offers two +1 mm Inconel exhaust valves, one for hydraulic tappets and one for solid tappets.

How to choose

Same size and same material: the type of tappets in the cylinder head makes the choice.

When reinforced valves become necessary

• Moving to higher boost (RB20DET)
• More aggressive camshafts
• Cylinder head converted to solid tappets (SL version)
• Track or drift use
• Cylinder head rebuild with tired exhaust valves

Vehicle compatibility

OEM part number (exhaust valve): 13202-79S10 (RB20DE) ; 13202-80S10 (RB20DET)

Don't forget the inlet valves

With the RB20 cylinder head open, take the chance to replace the inlet valves and the valve stem seals too.