free play in injector spacer

[Konstantin]

Hi guys, I removed my cover today to inspect camshafts. They looked good, but in couple places I find brownish spots. What concerned me is one of the injector shaft rocker spacer is moving kind of freely. I cranked engine and while other spacers are evenly covered in oil, this one is kind of lubricating good until lower part. I pressed on it to put it tighter against injector rocker arm and then oil started to flow from top part too. What needs to be changed? Miles on engine around 650,000. Cm 871. Thanks