Supertech BMW S14/S38 Manganese Bronze Intake/Exhaust Valve Guide 7mm Stem Oversize OD 12.065mm

If you're rebuilding the top end of your BMW S14 or S38 engine, getting the valve guides right is crucial for proper sealing and smooth operation. These valve guides from Supertech are made from manganese bronze, a material known for its good wear resistance and ability to handle the heat and friction inside the cylinder head. They are designed with a 7mm stem diameter and an oversize outer diameter of 12.065mm, meaning they are intended to be honed to a precise fit after installation.

Manganese bronze is a popular choice for valve guides because it offers a good balance of durability and lubricity, helping to prevent excessive wear on both the guide and the valve stem. This particular guide is an oversize OD version, which is common when the original valve guide bores in the cylinder head have become worn or enlarged. After installation, these guides will need to be honed to the correct size for your specific valve stems to ensure optimal performance and longevity.