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I have a 05 stock Corvette that developed a ticking noise inside the engine. After failed attempts to solve it with oil additives I tour it down and found the #7-cylinder exhaust valve lifter roller’s bearings had failed causing the roller to jam up long enough to cause a small flat spot on it, cause the roller to be sloppy (you can move it side to side and up and down about .1”) and damaged the cam. I am in the process of replacing the cam, putting in new LS7 lifters and new lifter trays. My big concern is what caused this in the first place. It may have just been that the lifter failed due to age, the engine has 118K miles, or it could be a lubrication issue. I have looked in this forum and other web sites to learn who the lobes and lifter rollers are lubed but have found nothing that sounds correct. There is one post on this forum that asked this same question but it is never answered and I have not found any others. Could someone with knowledge of these LS motors please explain this to me and I am sure others would love to know this too or steer me to a post that answers the question? I will include pictures of the bad lob and lifter roller. Bad cam lobe
If the lifter fit in the lifter tray becomes loose, the lifter can turn, with the result being that the roller on the lifter doesn't track true on the cam, and will skid instead of roll. There are other possibilities as well, such as what you mentioned.
Mine is an LS2 and the lifter tray is fine. You can see from the wear pattern on the cam lobe that the lifter roller was running true or the wear would have been uneven or at least that is my conclusion. I just rechecked and there is no rotation of the lifter in the tray, it is soled.
