2012 Yukon XL Denali 6.2L Cam Swap Thread

[ls1frc]

You will gain with a cam, even through stock manifolds. Depending on the use of the truck, headers may have big drawbacks.

-Ticking noise in the cabin
-High flow cats do not filter as well as factory cats

Everything has tradeoffs. I ran my old 99 vette with heads/cam/manifolds and it still trapped in the 120s.

I have headers on my Yukon and I flip back and forth all the time whether to take them off or not.

 

[Geotrash]

You will gain with a cam, even through stock manifolds. Depending on the use of the truck, headers may have big drawbacks.

-Ticking noise in the cabin
-High flow cats do not filter as well as factory cats

Everything has tradeoffs. I ran my old 99 vette with heads/cam/manifolds and it still trapped in the 120s.

I have headers on my Yukon and I flip back and forth all the time whether to take them off or not.

Thanks for the added perspective, Mike. That's one of the reasons I haven't considered headers or a modified exhaust. I also really like the sound of the stock exhaust system. My main objective for this cam upgrade was to improve towing power and long-term durability/reliability. I'm not looking for outsized performance gains - the 6.2 already satisfies.

 

[Geotrash]

Minor update: Since I have a couple of extra days of waiting for parts, I decided to order a Trucool 40K trans cooler and will hook it up while I have the grille off and existing cooler lines detached. Should arrive today. I read the other threads on how to mount it (good stuff, thanks all!), and have decided to simply delete the factory cooler and plumb the 40K in its place.

 

[Geotrash]

Made good progress today. Got the heads on, torqued down and all of the rocker arms installed. Drivers side exhaust manifold is on.

Lessons learned:

1/ Both timing marks need to be at 12:00 for the #1 piston to be at TDC on the compression stroke to start the torque sequencing on the rocker arms.

2/ A jack and a couple of steel punches are miracle workers for getting the exhaust manifolds to line up.

3/ The ARP head bolts need to be torqued with their special lube on the threads and between the bolt heads and the washer, but the bottom washer surface and the machined bolt surfaces on the heads need to be cleaned with brake parts cleaner and dry for proper torque values and clamping force. I’m glad I took the extra time to look up the procedure on their website because they did not include an instruction sheet with bolts.


Sent from my iPhone using Tapatalk Jo

 

[Geotrash]

Finally finished the job today and it fired right up and ran great! Couple of concerns though: 1/ there’s quite a bit of valvetrain clatter. It’s not terrible but definitely noticeable. I’m hoping it will quiet down after running some more and getting those lifters well pressurized. Seem normal to y’all? 2/ oil pressure is 5-10 psi lower than it was before I started the job. I installed a new o-ring in the pickup tube and also installed a new oil pressure sensor, deleting the screen. Since I ended up deciding to keep the OEM oil pump in place, the only thing I can think of is that the cam bearings may be looser now, but I also put in conventional 5w-30 after the work was done to run it with, knowing I would soon be changing it again within 100 miles or so. Without the VLOM stuff, if anything I thought the pressure would go up. Anyway, I’ll finish butting everything up tomorrow and take it for a ride. Can’t wait to feel how the new cam performs! Has a nice subtle lope to it!

 

[Geotrash]

So I fired it up this morning and it's definitely much quieter overall. However there's one lifter that was knocking loudly this morning and never fully settled down but got considerably quieter after running at 2500 RPM for a minute or so. I broke out my mechanic's stethoscope and it sounds like it's on the #3 cylinder. I'll get it out on the road today and see if some sustained driving will work it out.

 

[ls1frc]

Congrats, that is always satisfying doing that big a job and it starts right up.

First cold start post install will be noisy for a good 10 minutes, then will quiet down.
Aftermarket cam will always be noisier in general

Johnson 2110 lifters are slow leakdown, so will be a bit quieter than factory replacements.

My Morel LS7 replacements quieted down after a couple thousand miles. They're very quiet now, so I'd just give it some time.

 

[Geotrash]

Congrats, that is always satisfying doing that big a job and it starts right up.

First cold start post install will be noisy for a good 10 minutes, then will quiet down.
Aftermarket cam will always be noisier in general

Johnson 2110 lifters are slow leakdown, so will be a bit quieter than factory replacements.

My Morel LS7 replacements quieted down after a couple thousand miles. They're very quiet now, so I'd just give it some time.

Thank you, Mike! Very helpful and reassuring - especially considering I've only run it for maybe a total of 20 minutes so far. I'll keep everyone posted.

 

[ls1frc]

Did you measure pushrod length? With new lifters/cam, you're just guessing if you threw in only 7.400". I didn't read entire thread to see if you did already, just a suggestion.

 

[Geotrash]

Did you measure pushrod length? With new lifters/cam, you're just guessing if you threw in only 7.400". I didn't read entire thread to see if you did already, just a suggestion.

I didn't measure them but they're supposed to be 7.400". I ordered the cam, lifters, pushrods and springs as a set from Roger Vinci. Side note: I did *not* end up having the heads milled down by .0025 as originally planned and instead just had the machine shop clean them up, check the valves and seats, and make sure the mating surfaces were clean and smooth. It should be a pretty standard setup, so I'm at a loss for why it's so noisy.

I drove it for several miles on the highway this afternoon and then changed the oil before driving it some more. The valve train is still clattery - sounds like an old Dodge slant 6, with a couple of them louder than the others. Here's a video I made today to illustrate what I mean.

https://youtu.be/uD8emIEy6Ww