Web Camshafts offers Shortened Valve Guides for many applications. Web Valve Guides are often made from C360 Bronze Material (some applications may use a different material). This Material is often an upgrade over the stock guides, and is used for its thermal and wear characteristics.
Valve Guide installed heights are important to consider when thinking about using a higher lift camshaft. Higher Lift Cams move the retainer closer to the Valve Guide, and guide seal, than a lower lift camshaft. This tightens the Retainer to Guide Seal clearance and can cause damage to the Valve Guide, Valve Guide Seal, Valve Spring Retainer, Camshaft, and other Valve train components from not having enough retainer to guide clearance.
We recommend checking Retainer to Guide Clearance on every engine, this is because it can result in sever damage if not set correctly with enough clearance. We recommend a minimum clearance of .025" (.030" recommended).
Depending on Valve Guide Design, there are sometimes several options to correct the issue.
- Depending on guide design, some guides can be sunk farther down into the cylinder head to provide more retainer to seal clearance. This method is sometimes the recommended method when you still have good valve guides that do not need replacement, and is often slightly easier to do than a complete guide replacement. The issue with this method is that some guides can not be sunk due to the design. This also results in the valve guides protruding farther down into the ports, which could hurt overall cylinder head flow. This can be corrected by grinding the valve guides back down to match the profile of the guides originally, or you can just do the recommended thing and sink the guides before you get the cylinder head ported, not afterwards.
- When guide design doesn't allow sinking the guides. valve guides are worn, or you are just looking for an upgrade over stock valve guides; your option is to use a shortened valve guide from Web Cams (or other manufacture), if available.
- your third option is to remove the valve guide seal, this sometimes will create enough clearance, sometimes not. Doing this though is not recommended as it likely make the engine begin to burn oil, etc.