What causes "cam walk"?

Ricks70Duster340 said

I am a member of another forum and saw a guy with a 440 & hyd roller cam have his engine ruined because the cam walked. He used a bronze drive gear and one of those cam buttons that was two-piece with a little bearing in between (he got it from Manini but 440 Source looks to sell them too). He said he installed it with .005 clearance between the button and the timing cover. The failed cam button made an impression on the inside of the timing cover. When he took the cover off he saw the button had fallen apart.

What would make the cam walk like that?

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I took a look at the thread and I don't know what happened. Looked like a stamped cover which is really iffy with a roller cam. A stamped cover usually needs to be reinforced for a roller cam. I always use a billet timing cover for roller cams but some people don't want to spend the money for the billet cover. In this case it sounds like the guy lost the entire engine due to the cam walking. That doesn't happen very often but it can happen. I've seen a fair amount of damage in roller cam engines over the years due to cam thrust issues. BB Chevy motors chew up the block, other engines eat into the timing cover. Lots of stuff gets destroyed if the cam moves out of position.