Damaged head. Why?

[BrokenTsi]

Last year, I took the stock head off my car and built it up with crower springs/retainers etc...

I had a machine shop do a valve job and resurface for me. I bolted on the new head with a new set of comp101200's. The car only ran for 20 seconds because the machine shop messed up some guides and the valve job, and the compression was low, even zero in some cylinders. Not a huge deal, I got another head and fixed it and swapped over all my parts. Car runs great.

When I removed the cams from that damaged head, I noticed that only one "cam journal" was scored real bad. It was bad enough that it shaved itself from the inside out, and I would have never known it was bad unless the valve job on that particular head was bad. It almost filled up the oiling hole with metal. Of course, now that head is in the garbage.

My question is, what would cause that? That head was on my car running for over a year prior to the build, and all I did was have SS valves and springs put in. Now I'm worried that my head could do that at ANY time, and I would have no way of knowing it. I know how to properly install cams too. So whats the deal? Any ideas?

 

[dsm-onster]

I had a machine shop do a valve job and resurface for me. I bolted on the new head with a new set of comp101200's. The car only ran for 20 seconds because the machine shop messed up some guides and the valve job, and the compression was low, even zero in some cylinders. Not a huge deal, I got another head and fixed it and swapped over all my parts. Car runs great.

That would be a huge deal to me and I like doing my own head work. . . They should know better. Did you get at least a partial refund?

When I removed the cams from that damaged head, I noticed that only one "cam journal" was scored real bad. It was bad enough that it shaved itself from the inside out, and I would have never known it was bad unless the valve job on that particular head was bad. It almost filled up the oiling hole with metal. Of course, now that head is in the garbage.

Wait, I'm confused did you swap this bad cam into your new head that now runs great. You did say that you 'swapped over all your parts'.

My question is, what would cause that? That head was on my car running for over a year prior to the build, and all I did was have SS valves and springs put in. Now I'm worried that my head could do that at ANY time, and I would have no way of knowing it. I know how to properly install cams too. So whats the deal? Any ideas?

I actually bent my stock cams when jumping my timing belt last. The hard as heck stock cams. But no cam journal damage... or better no cam tower damage... When you mean "cam journal", you mean on the cam not in the tower, correct?

 

[BrokenTsi]

Yeah, the machine shop took care of me. They did another head for free.

The cam itself was fine. The "cam journal" I'm referring to is where the cam sits in and is bolted in. The little oiling hole on the bottom was all scored up, but I cant think of a reason why this happened.

Im trying to think of a reason why this would happen. Because I would have never known that would happen, if it weren't for the bad valve to begin with. When I was taking the cams out, I noticed that the journal where the cam sits was all scored up real bad. And that head was on my car for a full year, and was perfect before all this. Now's its a paper weight.

 

[Defiant]

Shavings or grit from where ever (was the head bead blasted?) wound up getting pumped into that bearing. Part of a plain bearing's job is to have "imbedability" just for this circumstance, and to be able to "soak up" contaminants instead of being destroyed by them- it's why bearing babbet is soft instead of chrome. If that bearing was only scored as you say, without serious damage to the cam, it could have been re-welded and saved- except that DSM heads are so plentiful and cheap.
The Model A Ford fenders we used to throw away in the seventies would bring several hundred dollars today. So it goes.

 

[BrokenTsi]

That head was resurfaced too many times anyways. It was pretty much at the end of its life.