It would be hard to get a total engine failure from a bad VLA. The valve tips get pitted and chipped from pounding and the noise gets annoying but thats about it.

I have never seen a bad set cause anything other than local dammage. It is best to fix it before it messes up the valve tips since repair of the valve tips requires removing the heads.

The noisey VLA on startup sounds like you have one leaker that is slow to pump back up. It probbaly makes noise only when it that valve ends up open over night. Under that load it may be leaking down. It should still pump right back up.

You have some high temeratures!!! Wow. IF there was ever a case for using the severe service maintenance schedule yours would be it. For that matter I would think synthetic oil would be a good call as well.

Good Luck,

Kevin