I'm currently in the process of doing a heads, cam, intake build in my 2000 C5 FRC. I plan to document the rebuild process but once you've seen one tear down you've seen them all. At least thats what i thought until i pulled the stock cam out of the car. Take a look at the huge amount of wear in the pictures below. Somehow the car was still running fine when i put her away a few weeks ago. I guess i picked a good time to finally decide on putting in a new cam, needless to say new lifters are going in as well.

Anything else i should be looking at to ensure that this doesn't happen again to my new parts? This was the the very first lobe on the cam, closest to the front of the engine. Do you guys think i need to pull the lower end apart to see if the metal missing from the cam damaged anything down there?

 

What does the corresponding lifter look like?

Steve

 

I'm going to guess "sideways."

To the OP, that would have sent a lot of metal though the engine...

 

Somehow all of the lifters, including the one on that lobe looked fine and rolled smooth. And it was in the correct orientation when I removed it. So how exactly that happened I still don’t know. I was told by a local engine builder that he seen similar issues on a few other LS1s. I’ll be tearing down the bottom end soon to look for any other damage.

 

How many miles are on that engine?

 

Only 110K on the engine. These LS's are typically know to be bullet proof for much longer.

 

Hard to say what caused that kind of damage given that the lifter looks fine. I would guess a defect in the cam lobe itself and/or poor oil change maintenance history. Keep us posted on your rebuild!

 

I've been talking to a local engine builder and according to him its not a uncommon failure. I pulled the engine a few days ago and torn into the bottom end. Sure enough the oil in the bottom of the pan was filled with metallic "glitter" and pieces of the cam were embedded in the main bearings. If this wasn't caught the engine would have been toast sooner rather than later by the looks of it. All of those dots on the bearings are the cam shaft material "welded" to the softer bearing material.

 

I had to sit and think about “not uncommon” for a few seconds. Lol.

 

Wow that's a gnarly failure for sure but pretty much what I expected to see in the bottom end. I'm surprised the bottom end didn't get worse sooner! Now you've done this work you'll be well on your way to a strong reliable engine soon enough.

 

the brown plastic inserts I think are called lifter trays are all that keep the lifter in the correct orientation. They can crack at one corner,or just wear out. anytime the heads are off they need to be changed..

 

That's not a common failure. There haven't been many posts for cam or lifter failure on any of the forums I visit where LS engines are the primary power plant. Most of the time, a failed lifter is the cause. It's also hard to imagine that the engine could have been running well with that damage.

 

Yeah. I haven’t seen anything like this kind of failure. This motor must have been apart in the past. Something is going on here that isn’t being disclosed.

 

Believe me, I'm at just as much of a loss as you guys are. I bought the car with 75K on the clock and its at 110K now. The car ran pretty damn good when i put it away. Oil and filter were always changed prior to the cars oil changed suggestions, never ran low or lost pressure. Every indication looks like the motor is as is from the factory, all factory hardware gaskets etc. The lifter was straight when removed and the lifter trays were in one piece, however will be replace when i reassemble.

Good news is that I ran over to the machine shop with the crank today and was told that the damage is surprisingly minimal. just planning on polishing the journals -0.001 and she'll be good as new so I'm told.

I'll be starting a thread in the near future of the rebuild process. I'll post a link here once i get a chance to put something together for anyone thats interested.

 

I've seen that a number of times with aftermarket cams. Don't recall it with a factory cam. Is the lifter tray in good condition?

 

IIRC way back there was a TSB out about thin walls on the lifter trays, and yes there were a LOT of cars affected. It does not take much wiggle of the lifter to start a wear pattern, and the thin walled trays would allow that wiggle. I think it was 2001 model year when it showed up.

 

I'm interested. (I have 04 with the LS1).

 

To anyone thats interested I started a thread to document this entire project yesterday. Heres the link: https://www.corvetteforum.com/forums...e-rebuild.html

Lifter trays appear to be in good condition but do have that brittle plastic feel to them, like if i dropped them is might crack. I think thats the most likely cause for this failure.

I'd like to think that it was something done by the previous owner that caused this but i'm pretty good about inspecting my oil and filter for metal etc. at oil changes. I defiantly wouldn't have missed the amount of material that came out of the engine when i just drained it. This damage must have been in the past 3000 miles or so.

 

My memory is that the lifter trays that were a problem had the number 10 identifier on them from the molding process. What we don't know is how much the plastic softens with temperature. It might be that they allow a little wiggle when hot and are fine when the engine is cold and apart. Also with a used car we seldom know history. A blown radiator hose or a chronic leak that doesn't allow the coolant system to pressurize can cause coolant boiling around the cylinders and heads. So that is a possibility.

You are on the right track careful disassembly and cleaning is in order. You will always doubt if you got every last wear particle out of the engine. From the looks of the bearings, you wisely took the engine apart JIT. For sure the wear particles will be magnetic, so a magnet tipped oil drain bolt might be in order. Even fully dipped blocks can have a little metal nit hidden that finds its way into the lube system.

 

That damage is the result of loss of spring force over time. The stock springs are pretty much done above 50K miles and weaken such that can't control the valve train resulting in lifter lofting at higher RPM's. IIRC, Bauer Racing has documented how the springs weaken and recommend a refresh when the motor gets up in miles.