This is some thing I should know but I find my self 2nd guessing my self ..

I had my hea assembled by a engine builder and picked it up a few days ago.. I was looking it over and noticed some of my rockets were " sloppy" loose .. So I pressed on them and my lifter compressed down with no resistance ... But the one beside it was rock hard ... Why are some of my lifters mushy and some hard .. ?

All the spare lifters I have are hard. Are the mushy ones shot ?