My son just rebuilt his 460 in school. It fired up and ran good for about 15 minutes and then it sounded like it had a stuck valve.

The first thing we thought was that he forgot to tighten a rocker arm. We pulled the valve covers and everything looked good there so we thought lifter.

We pulled off the intake and the first thing I noticed was that the lifters are only running on half the lobe of the cam. One lobe even looks like it could be contacting two lifters.

Have you ever seen this before?

Edit

I went and had another look before sending this and they gave him the wrong cam. Every 2nd lifter meets the cam correctly. Guess I will have to talk to the teacher. They will need to get him a new cam, bearings, lifters gaskets and the list goes on.

If a valve opens when it should be closed can it make contact with the top of a piston.

I was going to post a pick but I don't think I can. I may have to look at getting a photo bucket account.