Supertech Mini Cooper N14B16 / N18B16 Sodium Filled Inconel Exhaust Valve - +0.8mm OS - Set of 8

If you're rebuilding the top end of your Mini Cooper with an N14B16 or N18B16 engine, especially for performance applications or after significant wear, upgrading your exhaust valves is a smart move. These Supertech valves are made from Inconel, a material known for its exceptional strength and heat resistance, making them ideal for the demanding environment of the exhaust port. They are also sodium-filled, a feature that helps to dissipate heat away from the valve face and stem, further increasing their durability under high temperatures.

This set includes eight valves, each measuring 0.8mm oversize. Using oversize valves can be beneficial when reconditioning cylinder heads, allowing for a larger valve seat to be machined and potentially improving flow. The Inconel construction means these valves can handle higher cylinder pressures and temperatures without deforming or failing, which is crucial for engines that are driven hard or modified for increased output. The sodium filling is a notable detail; it's a common feature in high-performance exhaust valves because the sodium melts at operating temperature and circulates within the hollow stem, carrying heat to the valve guide for dissipation.

When installing these, remember they are a direct replacement for the stock valves but are oversize. This means the cylinder head will need to be machined to accept the larger diameter. It's always a good idea to consult your engine's service manual or a trusted mechanic to ensure proper installation and to confirm any other components that might need attention during a top-end rebuild, such as valve guides, seals, and springs.