DOD FAILED. CAM THOUGHTS

[decembersend]

I did this job on a 2012 Yukon XL Denali 3 times, thanks to a bad set of lifter trays. The whole story is here, but the last page summarizes where I ended up and offers some tips that might be helpful.

My wife and I tow a 7000 lb camper with ours, so I wanted a cam that would be good for towing. My priorities were durability, drivability and towing power. I ended up with a Cam Motion Stage 2 truck cam (3-bolt, no VVT, high-lift version), and am happy with the choice. It's specifically designed for the 6.2, which is important because the flow characteristics of the heads is different than the cathedral port head engines. I previously had a BTR stage 2 truck cam in there but it was designed for the 5.3 and after putting the Cam Motion cam in could feel a significant difference in towing performance (stays in 5th gear 90% of the time now), and I have to remember to keep my foot out of it or I find myself accelerating uphill.

For reference, I also have a 2007 Yukon XL Denali that has the stock L92 engine (VVT, but no AFM) that I sometimes use to pull the same camper, and the Cam Motion cam out-pulls that factory cam, both off the line unloaded, and on the highway pulling the camper. You will do slightly better down low with a single bolt VVT cam, but since my priority was durability, I didn't want to deal with the cam phaser and the possibility of problems with it. I haven't missed it.

Cam specs:
Duration at .050 - 212/220
Lift with 1.7 - .553/.553
Lobe separation 117
Intake center line 112

That what I was having issues with when I looked for cams myself it all said 4.3 or 5.3 or 6.0, and I want one for the 6.2 but haven't found anything yet. I'm going to look into Cam Motion and see what they have to offer.

I'm also going to check out your story now.

 

[swathdiver]

This is why I don't come on forums, they just make me want to buy and mod stuff lmao. Now I'm shopping for headers

If the forum kept track of which member caused others to spend the most, I think @Rocket Man would win hands down! LOL I'm still suggesting he get some custom pedals, he's modified everything else! LOL

 

[91RS]

You will do slightly better down low with a single bolt VVT cam, but since my priority was durability, I didn't want to deal with the cam phaser and the possibility of problems with it. I haven't missed it.

I've never seen an issue with the cam phaser system on a V8. It is a very reliable system. The only thing timing related on a V8 I've seen fail in the real world is the timing chain tensioner but that is easily fixed by changing to the LS2 style chain and damper and deleting the tensioner. I would never give up VVT on a big heavy vehicle like this and you can make the same power with a smaller cam which means better drivability.

 

[Geotrash]

I've never seen an issue with the cam phaser system on a V8. It is a very reliable system. The only thing timing related on a V8 I've seen fail in the real world is the timing chain tensioner but that is easily fixed by changing to the LS2 style chain and damper and deleting the tensioner. I would never give up VVT on a big heavy vehicle like this and you can make the same power with a smaller cam which means better drivability.

I agree that it's generally a reliable system, but there were a handful of reasons why I chose to forgo it:

1/ In my research, I ran across some people who'd had trouble getting their cam phaser to work right with an aftermarket cam. Another one here. And working with a limiter, which the OP may have to do, further complicates the process.
2/ I ran across lots of posts in this forum from people having cam phaser and related problems with higher mileage trucks - especially when towing. Here, here and here are some examples.
3/ Torquing the cam bolt requires removing the starter to get a tool in there to hold the flywheel. There are other ways, but none of them easy for one guy to do alone. PITA.
4/ Engines with VVT use a different tensioner, as you alluded to. While some said that using the older style tensioner (not spring-loaded) would work, I couldn't find anyone who'd accumulated more than a few thousand miles with VVT and the older style LS tensioner, so I could not assess the durability of making that choice.
5/ As best I could tell, VVT is good for only about 15 lb ft. down low and slightly better fuel economy.

Can it be done? Sure. Is it a hassle? Depends on his experience. Is it worth keeping for 15 lb. ft. down low? It wasn't for me, so I just felt it was worth sharing my experience with the 3-bolt cam for perspective - especially since I have one of these trucks that still has the VVT to compare performance with. I personally don't miss the VVT and I use my trucks in a similar way the OP described for his use cases for his truck. And the drivability of the Cam Motion cam remains excellent in all scenarios.

I'm not trying to change anyone's mind with this. Rather, I'm just sharing my rationale from my decision process in the hope that it will be helpful to others and illuminate relevant factors they may not have yet considered.

 

[91RS]

Tuning is a sperate issue, many tuners are scared of or don't know how to tune the VVT so you should definitely make sure your tuner is willing and able before making the decision to keep it.

Most of the "phaser" problems are really timing chain and tensioner problems. This may come off as belittling but most people here seem to have no problem firing the parts canon to avoid getting a proper diagnosis (either by paying someone or having a scan tool and the knowledge to use it). So when someone goes in and replaces a pile of parts to fix one problem no one really knows which part was actually bad. I've never replaced a phaser for a P0011, it was always a broken tensioner or the pin sheared off the cam (or someone was in there not knowing what they were doing and broke it or put it together wrong). That's not to say one has never gone bad but it would be so rare that I wouldn't consider it something to worry about.

Th flywheel holding tool should also be used to torque the balancer which has to come off to replace a cam so anyone who is doing that should already have some way to hold the flywheel to torque the balancer. I deleted the timing chain tensioner in my Escalade and also in my father-in-law's Sierra Denali and have had no trouble. I didn't delete it on my Yukon because I didn't know it could be done at the time I deleted the AFM on it but if/when I do the new Escalade I will be deleting the tensioner there, too.

It isn't just about the peak numbers. It sure feels like more than 15 ft. lbs. to me but regardless the point is that you can get similar results with a smaller cam by keeping the VVT which provides better drivability and durability of the valvetrain but with a better power curve and without having to have a higher stall torque converter which kills fuel economy and drivability. Some people are fine with the way a bigger cam and torque converter drives and if that's you, then that's fine. But if you want it to drive very similar to stock but with more power, then keep the VVT.

 

[hagar]

I use the Texas Speed stage 2 vvt cam in stock 6.2 trucks and its an absolute monster with zero low end power issues on the stock stall. It is a little tricky to get the idle dialed in at certain spots like approaching a stop with the stock stall, the cam pushes on tbe converter down low, but if you know what you are doing, it works great.

I would challenge anyone to floor one of the 6.2s with that cam, from a dead stop, and say it feels like it lost anything down low. The ability of a vvt cam to fill in power at all rpms can only be believed after you try one.

 

[hagar]

Traditionally you lose power down low with a bigger cam, and I am sure if you were able to hold the power down low enough on a steady state dyno, you would see some loss, but the truck in the real world would never be there. With the vvt cams, your camshaft is parked at maximum advance position, so it is in the position to make the most possible torque, then as your rpms increase, the cam starts retarding, as it retards, it starts swapping the characteristics of a fully advanced cam, for the characteristics of less and less advanced cam, until finally your truck is at peak torque, and the cam then ends up in fully retarded position, which allows peak hp production.

It does an amazing job of making power down low with bigger cams than you would Traditionally use for a heavy truck. The old keep it under 208 duration and such that was the old standard, isn't the same with vvt.

 

[decembersend]

I use the Texas Speed stage 2 vvt cam in stock 6.2 trucks and its an absolute monster with zero low end power issues on the stock stall. It is a little tricky to get the idle dialed in at certain spots like approaching a stop with the stock stall, the cam pushes on tbe converter down low, but if you know what you are doing, it works great.

I would challenge anyone to floor one of the 6.2s with that cam, from a dead stop, and say it feels like it lost anything down low. The ability of a vvt cam to fill in power at all rpms can only be believed after you try one.

Do you have the part number to that TS cam? The one I found says its for the 5.3. I know that it should work just fine I was just curious if you found one that meant for the 6.2

 

[hagar]

Do you have the part number to that TS cam? The one I found says its for the 5.3. I know that it should work just fine I was just curious if you found one that meant for the 6.2

25-TSPL92VVT-2 - TSP L92 Stage 2 VVT-2 Camshaft: 220/232, .600/.600, 113 LSA 107 ICL

 

[decembersend]

25-TSPL92VVT-2 - TSP L92 Stage 2 VVT-2 Camshaft: 220/232, .600/.600, 113 LSA 107 ICL

Thank you.

Aside from the DOD delete did you have to tune for the cam?