- Bang them out and cause damage to the head *BAD*
- Drill them until they fall out on their own so as to cause no damage to the head *GOOD*
Many builders don't have the correct equipment to properly remove and install valve guides, so they use force instead. Hammering an old guide out of a head can score and damage the head so as to not have a nice surface for the new guide. We have seen people with a guide they try to force out shatter, so then they end up forcing the hammer tool through the head to get the pieces out, nearly ruining the head completely. If you jam a new guide in the scored area it could leak and cause the engine to use oil. Many people will try to heat the head up first, but you still cause damage to the cylinder head every time you force a guide out.
We don't do this. We use a machine which drills each guide to the point that it becomes so thin that it falls out of the head. This way we cause no damage to the head casting and the new guide has a nice surface to sit in. The guide will sit in the head straight and true.
Picture below of the machine we use to drill out your old guides. It does an excellent job and assures a very clean and accurate replacement of your cylinder head guides:
Picture of old guides below:
Using the right equipment for something as simple as replacing guides is very important. Think about what a guide does. A guide has the following duties:
- Allows for proper valve alignment with the seat
- Prevent oil leaks between head and guide
- Secures valve seal in place around the valve and guide
Some people use the same hammer tools to pound your new guide in too. This can crack the new guide, or mushroom the end of it. Also very bad. Plus, hammering in new guides makes it difficult to have the same install consistency, so some guides are in too far and others are jammed in not far enough. It's amazing how many high end head builds we have seen with all of the guides sitting in a different spot. We all know how they are installing them!
Do you know what happens when your guide is too far off and the valve can't float on your seat correctly? Pic below is the perfect example:
The valve will bend itself to align with the seat. As it turns, it will bend again to align with the seat. It will do this over and over until it finally breaks and your engine is ruined. Was it worth it?
If it's not in straight, secure, and clean, then it can affect the life of your cylinder head and valves very quickly. Plus, driving around in an oil burning vehicle never looks good.
Have it done right by those very much experienced with your cylinder head! At Jacks Transmissions, doing it right not only makes the job cleaner and easier for us, but you get a superior head too. Win-win for the both of us!