I was talking to a mechanic today who told me that all modern engines (post lead in gas) have the valve guides knurled to allow lubrication to the valve stem. He's saying all new cars are this way.
Does this make any sense? Didn't sound right to me. I was told that knurling is a practice that is less desirable than replacing the guide.
Bill,
I do quite a few valve jobs on newer engines, and I have yet to see a head that had knurled guides from the factory. Knurling is an undesirable process for the auto makers because it is slow (read costly). Also, the knurled guides do not last as long as a smooth bore guide. If you are going to have your head rebuilt, and plan on keeping the Jeep for a long time, have bronze guides put in if they need replacing. The bronze wears better than new steel or cast guides, and will outlast a knurled guide by a longshot. They are a bit more costly than the steel guides, but not that much, and are well worth a few more bucks.
Chris
Thanks Chris, I knew what I have learned here and other places falls right in line with what you are saying. Just wanted to confirm it. This guy was obviously giving me a line or didn't know what he was talking about or both.
Bill
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