Hi All, I have a 2012 GMC Yukon XL Denali (6.2 L94) in which I'm experiencing repeated lifter failures in 2 different cam swap setups and could use your opinions on the root cause.

First time, January 2021:
Brand new Vinci Performance cam - 213/222, .578/.587, 115 +3A, 3-bolt. Non-VVT, non-AFM
New Vinci dual valve springs
New Vinci drop-in lifters and trays
New matched Vinci moly pushrods, checked for preload on assembly.
BTR trunnion upgrade kit.
After running for a few days, engine developed a chirping noise after a full-throttle runup to 5500 RPM merging on the highway.
The results are in the second 2 pictures.

Second time, September 2021
Brand new BTR Stage 2 truck cam - 212/218, .553/.553, 111, 3-bolt. Non=VVT, non-AFM
New BTR matched beehive valve springs
New Morel 6504 lifters, but kept the Vinci lifter trays since they were virtually new
New matched BTR moly pushrods, checked for preload on assembly.
Same BTR trunnions re-used and still in great shape
After running great for 8,000 towing miles, engine developed a chirping noise after a full-throttle runup to 5500 RPM, again merging on the highway.
The results are in the first 2 pictures. Very similar damage in both cases.

What's going on here? My mechanic and I think it's a bad lifter tray, and indeed, one of them has some play in it compared to Chevrolet Performance trays.

 

If it's on the same lobe that would be my guess too. Looks like the lifter was so loose it turned sideways in the tray. It's always good to replace the cams retainer plate during cam swaps so no oil pressure gets by the old flattened orange gasket. For only $18 it's a good piece of mind.

 

Thanks for your thoughts and second eyes on the pics. That's exactly what it looks like to my eyes, too. Unfortunately I didn't mark the lifter trays to ensure they went back into the same spots when I reassembled the engine the 2nd time, but both times it was a lifter mounted in the furthest right slot in a tray. And on two of the trays, that particular slot doesn't grip the lifter as solidly as the others do, and it permits some wiggle of the lifter body before it's fully seated. The Chevrolet Performance trays don't do that - they're a snug, firm fit on the lifters.

Yes, I did replace the cam retainer plate with a new one both times I did the job, and will replace it again when I put it back together this time. This time I decided on a Cam Motion Stage 2 "drop-in" truck cam with a little more LSA (117) to idle smoothly. (212/220, .501/.501, 117 LSA, 112 ICL) I also bought new Chevrolet Performance drop-in lifters and new Chevrolet Performance trays. Fingers crossed.

My only worry now is whether or not the shrapnel from 2 lifter failures has scored any of the main or rod bearings. I'm gonna run it and hope for the best. Worst case, I'll put in a new L9H crate motor.

 

How are you measuring the preload, and what preload are you running? I only use GM lifter trays even though I have no reason to avoid other brands. my lifters were very snug in the last set of new trays that I used. Does Vinci and BTR grind their own cams, or sub them out to other companies?

After 2 issues like this I'd be looking at lifters with a link bar.

 

New LS7 you mean

 

I used the Comp Cams adjustable length pushrod to get the proper length (7.400), and verified it with the old trick of tightening the rocker shaft bolt until the rocker contacts the top of the valve, then counting the turns of the bolt until it's tight. I forget what the number was for the Morels, but I made sure each was within the spec. Didn't have to make any changes to pushrod length, etc., thankfully.

I believe that Vinci does grind his own cams in-house, but BTR works with a "Tier 1 supplier" (widely rumored to be Cam Motion) for their grinds. I considered link bar lifters but fingers crossed that the new trays will solve my problem. If not, it's getting a crate motor, lol.

 

Right. Open to suggestions though.

 

make sure to get your ls7 lifters from a reputable seller. From what I understand, there are several chinese knockoff lifters advertised as LS7. GM Parts Direct, SDPC, Texas-Speed or your local dealer come to mind. I haven't had any issues with the johnson lifters in my build, but i doubt you care to spend $700+ on a set of lifters.

 

Should have highlighted where you said new crate L9H.

In terms of lifter suggestions I am running LS7 lifters, at least they are advertised as such, and I have no issues. I believe Red is running Morel and he says that they are much quieter than the LS7s he was running previously

 

Good call. Bought them through Summit and they arrived in a box sealed with a GM hologram label. No Amazon or eBay when I’m looking for OEM parts, ever.