If I'm seeing the pics clearly, it looks like some serious valve float going on there. That's why I asked about the pics, because adding lash caps always makes the geometry worse with roller rocker. The engine doesn't know or care where the pattern is on the valve tip, but it certainly knows when the valvetrain is unstable. I'd investigate further, especially geometry, so you don't have damage more serious than just a lash cap. I hate to see stuff get busted up when it can be avoided.
Thanks for the thoughtful response. I had not considered valve float.
Are you basing this on the pattern of the worn cap or the others?
All three, actually. The center cap in the photo clearly shows a star pattern typical of valve float/bounce. The third cap looks as though it has been abrading across the whole surface, while the first one looks as though it hammered through the surface hardening. Anytime valvetrain instability is present, it is like taking a jackhammer to all of the valvetrain parts. I like to use the example of taking a 16 pound bowling ball and sitting it on your foot. Then take the same bowling ball and drop it from three feet above your foot, and see how quickly you can get to an emergency room. The ball weighs the same, but the distance it had to close allowed the jackhammer effect. The springs may be strong enough for the weight of the valvetrain and cam profile, but it will have a hard time controlling the instability from incorrect geometry. I'll dig up a photo of a -1 head to show what it should look like without the lash caps.
