Exhaust Valves

Which valve can handle the heat and the revs when boost pressure and exhaust gas temperature rise in your project? Exhaust valves control the path of the combustion gases from the cylinder out towards the exhaust manifold. We bring together valve sets in various diameters and materials for you who are building or rebuilding a cylinder head.

Why the exhaust valve is particularly exposed

The exhaust valve sits in the hottest part of the combustion chamber and is not cooled by the incoming air the way the intake valve is. With higher boost, more power and more revs, the load typically increases, and an overheated valve can in the worst case burn or break. That is why exhaust valves are available in heat-resistant materials, e.g. Inconel from Brian Crower and superalloy from Ferrea.

How to choose exhaust valves

Start with the engine code, as the valves are made for specific engines, e.g. Honda/Acura K20, Subaru EJ257, Toyota 2JZ-GTE or Nissan VQ35DE. Then compare:

• Head diameter: stock size or oversize (e.g. +1 mm), which typically requires machined valve seats.
• Stem diameter and length: must match the valve guides, spring installed height and valvetrain geometry.
• Seat angle and head shape: e.g. 22, 24 or 30 degrees and a flat or dished head.
• Keeper grooves: e.g. standard or triple groove, which must match the valve keepers.

A larger valve does not automatically give more flow; it depends on the ports, valve seats, camshaft and your power goal.

Installation and the rest of the valvetrain

New exhaust valves are typically installed together with valve seat machining and a check of the valve guides, and the springs must suit the camshaft and revs. Consider replacing the intake valves at the same time so both sides are sized for the same project. You will find more valve types under engine valves, and the category also includes brands such as Supertech, GSC Power Division and Edelbrock.

Frequently asked questions

Should I replace all exhaust valves at once?

The valves are typically sold as sets for a specific engine, e.g. with 8, 10 or 12 pcs. If you replace them all at the same time, you get identical dimensions and material in every cylinder, and it fits naturally with a cylinder head rebuild.

What does oversize mean on an exhaust valve?

Oversize, e.g. +1 mm, means a larger head diameter than stock. It typically requires machining of the valve seats, and there must be sufficient room in the combustion chamber and clearance to the pistons.

How do I know the valves fit my cylinder head?

Compare engine code, head and stem diameter, length and seat angle with the cylinder head specifications. If a dimension differs, it can affect valve clearance, spring installed height and sealing, so always check the data for the specific part number.