Fijensen

I'm changing my motor. I have a used one with 40k miles on it. I cleaned out the auxillary ports, cleaned, oiled, and installed the valve sleeves. It appears that one of the stems that turn the sleeve is a little longer than the other. when I put it in and tighten the LIM down, it won't turn. If I back the bolt out a turn or 2 it turns frrely. The spring doesn't look stretched. I was wondering if anyone else has had this happen, or had a cheap fix for it. TIA