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, other web sites and even in 05 factory service manual to learn who the lobes and lifter rollers are lubed but have found nothing. There is one post in this forum that asked this same question but it is never answered. Could someone with knowledge of these LS motors please explain this to me and I am sure others would love to know this too. I will include pictures of the bad lob and lifter roller (the picture shows the small flat spot). Before you ask, my lifter trays are fine and the flat spot on the lifter roller is side to side which would not be the case if the lifter had spun at all. If I was to take the valley cover off would that show a lubrications path to the lobes?

 

ALWAYS change the lifter trays when u change lifters.

 

The biggest cause IMHO is possibly low oil volume. Ie: down 1+ qrts.

 

. Only use OEM Lifter trays. Order straight from your dealer. NEVER use the Chinese lifter trays.

 

could have been lack of lubrication or the lifter turning slightly in the tray. But i would say with a new cam, LS7 lifter and new trays you should be perfect after that.

What oil are you running?

 

I use Valvoline synthetic 5-30 high mileage. It will be changed again when I get it all back together. Any suggestions as to what oil to use? I am going to use new lifter trays from GM and LS7 lifters. The oil was never low. Should I take the valley cover off inspect and replace "O" rings and gasket?

 

I dont think the valley cover coming off is needed. That oil should be fine. I use 5w-40 oil since I'm in Texas to help it from getting too thin. But for a car thats a casual cruiser 5-30 is fine

 

I'm in the heat of Arizona. Should I be using that 5w-40 also? Oil pressure when hot goes down to 27 but is around 40 cruising. Still would love to know how the lobes and lifter rollers are lubricated.

 

Lifter bodies and cam bearings are pressure lubricated. Cam lobes and stock lifter rollers are splash lubricated.

Here's a diagram and description of the LS2 oiling system from the shop manual. Hope this helps

 

Thanks for the info. I figured the lobs and lifter rollers were splash liberated but wanted another who knows for sure to confirm by assumption. Any take on what oil weight I should be using here in the heat of Arizona?

 

My take.... It's just a flaw of the LS engine. My 5.3 Colorado developed the same issue, it's came from the hydraulic lifter. It had 145k on it. My dad's 6.4 hemi in his ram did the same thing, the collapsible lifters used for AFM do this.

Look up how common it is on the 5.3, it's insane.

 

This certainly isn't the first time someone on the Corvette Forum posted photos of a damaged lifter roller and a damaged cam lobe.

If the lifter is not rotating in a damaged lifter tray, then the question is ....
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1. Is the lifter roller and cam lobe for some reason not getting any splash lubricant on it so it finally runs dry and the roller chews up the cam lobe ?

2. Is the lifter roller just seizing on the lifter for some strange reason, so it stops rotating as it travels around the cam lobe (chewing them both up in the process) ?

3. Does the lifter stop getting pressurized oil fed to it internally for some reason ?

4. Is either the lifter roller or the cam lobes not properly heat treated / hardened during manufacture ?

Other than using aftermarket valve springs that have excessive seat and open pressure, or maybe a broken valve spring, or a bad lifter tray, about the only things that I can think of that would chew up a lifter roller and the cam lobe that the roller rides on are one of the 4 items I posted above.

By reading the various threads here on the Forum, this problem seems to be happening a lot (if you think about it, it shouldn't really happen at all)

 

Well the car has 118K miles on it and it ran fine up to this point so not #4. The lifters on both sides of the bad one are fine and the car ran fine, that is you could not see any difference in rocker movement when at idle. So I do not think it is #3 and that leaves #1 or 2. If the lifters and lobes right next to this one are getting splashed lubed enough do not thing this one would have a problem. I think it is #2. The roller bearings that support the lifter roller seem to have gone bad or the shaft that they roll on or the inside of the roller. I can grad the roller and move it side to side and up and down. Not a lot, I measured .1" of movement but the roller is not only sloppy but it is rough as you rotate it. I agree that this seems to be a recurring problem dealt with on the Forum and in other places on the web. I am hoping the new LS7 lifters addressed this problem and will be much better. My thanks to all how have been so kind as to reply to my post and give me information and advice.

 

Dan ...

From everything I have read, the OEM LS3 and LS7 lifters are exactly the same ... with the same GM part number.