Hi All, long time listener, first time caller. I've been working on a cam swap in an L94 in a 2012 Yukon XL Denali. 117K miles on the original cam, no issues with noises or oil pressure beforehand. Swapped in the new cam with matched lifters, springs, pushrods and seals: Gross lift: 578/587, Duration: 213/222, Lobe separation 115, +3 advance. I also replaced the valley cover with the GM DoD delete flat valley cover and put a new (correct) o-ring in the pickup tube, but left the stock HV oil pump in place. Used Permatex assembly lube and cranked it over without fuel or fire for 30 seconds until I got oil pressure, and fired it up. Ran it for a couple of hours total over a couple of days and it made great power, but the oil pressure stayed at 15 indicated at hot idle and 30-35 at 2000 on the highway. The normal new cam valve train clatter diminished but the engine developed a loud chirping/clacking for the last run before I shut it down and pulled the cam to see what was going on. The cam showed classic signs of oil starvation (pics attached). My best guess is that I either nicked the pickup tube o-ring when I put it in, or didn't get it seated right and the pump was sucking an air/oil mix.

I'm planning to drop the oil pan again and replace the oil pump with a new Melling 395HV, keeping the 70 psi bypass spring it comes with in place. I'll replace the pressure relief valve in the oil pan as well.

My question for you: do you think it's okay to run this cam and lifters as is, or should I swap it all out with a new parts? What's your opinion of the damage? About half of the lobes have enough of a ridge where the lifters run to catch a fingernail, but still look pretty good to the eye. One has a slightly deeper gouge, as you can see in the pics.

Also, here's a video for the sound it was making before I pulled the cam:

Thanks for any and all input.

 

Hi All, update here. I've been working with Roger Vinci on this (Vinci High Performance) and I've never experienced such great support in automotive that I can remember. He's been a great consultant every step of the way, and thinks that one gouge may be deep enough to have gone through the hardened layer. He's asked me to send it back for inspection. He's also offered to warranty it out, which means a regrind or a new cam, even though neither of us believe his parts were at fault. THAT's service. He's out of lifters though so I'll likely get new LS7 style lifters from Summit. I'll stick around here though and try to help out others as I can. Hard to expect help on any forum when I haven't first given help to others.

 

You need to look at the lifters.

 

Thank you, I agree. I'll have them out this weekend. Got the cam out on the bench yesterday and took a better look. The damage is much worse than I initially thought, with more than half of the lobes exhibiting significant scars and even some spalling on the ramp. Again, oil pressure was lower than I'd like but not zero (15-20 psi indicated at hot idle, 35 psi on the highway.), and the cam was dripping with oil when I removed it, so I'm shocked at seeing so much damage after less than 2 hours of total running time.

Roger Vinci has kindly agreed to take the cam in for further analysis and offered warranty support. He's been fabulous to work with through this whole episode. Will hopefully know more in a couple of weeks but will report back on the lifters in a couple of days.

 

Also, Vinci is out of lifters at the moment, so Roger suggested some alternatives. Going to roll with Morel 6504's when the replacement cam comes.

 

What springs were you using, who set your springs up? What lifters?

I had to replace cam and hv lifters rebuilt due to engine builder not having enough spring pressure on the seat.
Theres also lots of examples of new lifters failing

 

The springs are dual, but possibly overkill for this cam. Everything was spec'd out by Roger Vinci at Vinci High Performance and purchased as a set, including the cam, lifters, pushrods, springs and seals. The only parts of the valvetrain that weren't part of the set were the valves themselves and the rocker arms. The valves are the originals, and I kept the stock rocker arms but installed a BTR trunnion upgrade kit.

 

Just realized that I never updated this thread with the root cause. Turns out the lifter trays I purchased weren't holding the lifters firmly, allowing them to twist slightly under higher RPMs. The seller swore that they were OEM, but alas they were not. After twisting lifters wiped a second cam, I finally found the root cause to be the trays. I replaced them with genuine GM from a known-good source and no more problems in 20K miles since. Ended up with a Cam Motion Stage 2 truck cam and I couldn't be happier.

Here's a video showing my lifters and the defective trays compared with the OEM trays:

 

Which Stage 2 cam?? C.M. makes different grinds for 5.3, 6.0, and 6.2, and any one will bolt into any LS.

 

This one. The fact that it's a 6.2-specific grind was a key selling point for me. It has a smooth idle and does great pulling a 7500 lb camper:

"High-Lift" Version:
Grind # XA212/325-XA220/325-17+5
Duration at .050 - 212/220
Lift with 1.7 - .553/.553
Lobe separation 117
Intake center line 112

https://cammotion.com/camshafts/6-2-...212-220-117-5/

 

OK thanks!
Do you want to divulge the seller who misrepresented the trays as OEM?
It would be a service to future buyers.

 

In the video it sounds like "So here is the Vinci lifter tray"
Might explain why they were so helpful.

 

Yes, that's correct Gene. And possibly so. He did warranty the cam though, but claimed that the cam damage was caused by debris, despite the consistent curvy edge pattern engraved into many of the lobes on the first cam (Vinci) and the second cam as well (BTR stage 2). At that point I washed my hands of the man and went a different route with my lessons learned.

 

See above. Vinci.

 

when I first heard the video, I thought it sounded like a Lutyens lifter. I’m really glad found out what it was.

I’ve read about knock off trays causing this very problem on YouTube. After seeing similar complaints from bad trays, I ordered new GM pcs and GM cam plate from Summit Racing. I love SR

 

How do the BTR lifter trays compare to GM or are they actually GM? Engine is being assembled at a machine shop in the next week or so and the lifter trays I gave them were BTR's from g8only.com. Certainly don't want to have an issue and will get some genuine GM trays if the BTR trays aren't equivalent.

 

I think Brian uses GM trays, but I would 100% consult BTR and make real sure, before that shop installs a potential problem maker. If they are not GM trays, you don’t want them, no matter what they tell you. I’d install used GM trays before I put aftermarket trays in any engine of mine.

 

FWIW......When I want new GM trays, I go to my local Chevy dealer. One of the few things I buy at the dealer, and willing to pay a bit more for, knowing I'm getting genuine GM trays. So-When I go to a GM dealer, and the trays have GM part#s, they must be GM trays. I seem to remember a joke along those lines??....