DoD 5.3 LC9 motor help

Over the weekend, I helped a buddy who wanted to clean his rocker arms and push rods to get rid of a small tick in his 07 Avalanche 5.3 LC9 motor with active fuel/ displacement on demand.

When we put the motor back together, we changed he oil and ran it for a couple minutes and it was good. When we started it up again, it had a massive lifter tick, like a blacksmith hammer forming away.

We pulled the valve cover and found a few of the rockers did not have tension, especially the #1 intake valve. It had ~1/8th" gap. All of the valves would move when we rotated the motor.

It looks like a lifter collapsed. Has anyone ever run across this on one of the cylinder shut down motors?

The DoD lifters are notorious for collapsing. Replace all the lifters, as well as the Variable Lifter Oil Manifold (VLOM). When you have the lifters out, make sure to check the cam, as I've seen the lifters fail and take out the cam before. And while you have the intake off, it's a good time to put a new oil pressure sender in and make sure to clean or replace the screen filter under the pressure sender.

the best fix that i've heard of is to swap in a non DoD cam and regular lifters.

former520 wrote: Over the weekend, I helped a buddy who wanted to clean his rocker arms and push rods to get rid of a small tick in his 07 Avalanche 5.3 LC9 motor with active fuel/ displacement on demand. When we put the motor back together, we changed he oil and ran it for a couple minutes and it was good. When we started it up again, it had a massive lifter tick, like a blacksmith hammer forming away. We pulled the valve cover and found a few of the rockers did not have tension, especially the #1 intake valve. It had ~1/8th" gap. All of the valves would move when we rotated the motor. It looks like a lifter collapsed. Has anyone ever run across this on one of the cylinder shut down motors?

Yep. Pull heads, replace lifters.

Knurled wrote:

former520 wrote: Over the weekend, I helped a buddy who wanted to clean his rocker arms and push rods to get rid of a small tick in his 07 Avalanche 5.3 LC9 motor with active fuel/ displacement on demand. When we put the motor back together, we changed he oil and ran it for a couple minutes and it was good. When we started it up again, it had a massive lifter tick, like a blacksmith hammer forming away. We pulled the valve cover and found a few of the rockers did not have tension, especially the #1 intake valve. It had ~1/8th" gap. All of the valves would move when we rotated the motor. It looks like a lifter collapsed. Has anyone ever run across this on one of the cylinder shut down motors?

Yep. Pull heads, replace lifters.

and cam, top plate with an ls2 non DOD plate, and program out the DOD.

The DoD failed on da boss's Suburban when he was down in Florida. Everything was flawless until they got off the highway and the engine dropped into 4cyl mode. Then one of the lifters came apart. Dealer down there wanted to replace the whole engine Failure when 4cyl mode engages seems to be a common theme.

We disabled it last month because it pissed him off so much. 10 minutes to find where it was buried in the tune (it is somewhere weird, not where it would be expected), 2 minutes to write to controller, and he's happy.

So if you program out the DoD before trouble comes,and keep the original lifers, can they still fail, or I guess I should say, are they less likely to fail?

Which LS engines have the DoD? My work van is a 2013 with 4.8, and does some funny things somes times when cold.

They should be less likely to fail if kept disabled. This isn't a hard guarantee, of course.

There are eleventy billion cam options for these and cams are easy. Replace lifters with regular units, and whatever other parts are required, and put in one of the available cams. I used a Vinci 210/218 .551/.551 cam in my 6.0. Loved that cam.