INSTALLATION TIPS

At AV&V Performance Lab, we have removed and installed hundreds of guides every year with no returns and without damaging the heads. Here is the way we proceed:

Removal: 

On non-hardened guides, we cut down the top portion of the guide first to make it flush with the spring seat surface. To do this, we use a piloted counter bore tool mounted on a drill press. We then heat the head to 250^o–300^oF in an oven for 30 minutes and then hammer the guide out through the combustion chamber. After the guide is free, we chamfer the valve guide holes to remove any burrs. (Note: On Twin Cam and late EVO model the OEM guides are hardened and there is no need to cut down the guide for removal. Simply heat the head and drive the guide out as described above.)

Installation:

For installation, we use the shrink fit method by heating the head to 250^o–300^oF and then freezing the guides. We also suggest applying camshaft assembly lube to the guide’s outer surface to help facilitate installation. (Never use thread locking compounds.) If you follow the correct procedures, the guide should enter the head half-way before you need to hammer on the driver. If you have to over-hammer the guide, you may have chosen an oversize that is too big. On Twin Cam and late EVO guides, we usually reinstall STD oversized guides if the old guides were STD to begin with. (Ultimately, there should be a minimum of .002’’ press fit.)

Reaming advantages using AV&V carbide Reamers:

There are two ways of fitting a valve guide; reaming or honing.

In the past, valve guide reamers were often overlooked in favor of the tried and true honing method, largely due to the early reamer’s poor piloting functions. Holding a consistant centerline and diameter was nearly impossible with these early reamers.

With AV&V carbide reamers, a 2’’ long pilot has been configured to ream each guide precisely and quickly. In the end, AV&V reamers eliminate each step associated with honing. They leave a clean, precise, and repeatable finish at a fraction of the time required for honing.

In testing, we have used the same reamers for years, and after reaming hundreds of manganese bronze guides, they are still maintaining exact tolerances.

The finishing touch:

It is important to clean the guide and oil galleries with hot water and soap using a nylon brush before final assembly.