Flapjack

Hey everyone. I don't post here often as I'm usually beating up on my Mustang. Now that I got it up to 1000 rwhp, I've kinda moved onto other projects... the number one being my truck.

I have a 2002 Chevy Avalanche Z71 with about 170k miles. The engine is burning oil pretty bad, so I decided to accelerate my plans to swap it.

I picked up a complete 6.0L LQ4 from an 03 Chevy Van and was told it would be a pretty direct swap. The place I got it from offered a 3000 mile / 3 month warranty, so the clock is already ticking. I plan on installing it this weekend, but want to make sure there are no "gotchas" here.

I've talked to the local GM performance shop here in Colorado Springs (RMCR) and they said I shouldn't need anything. They even said I could use the 5.3L intake and injectors, and wouldn't need to worry about a tune right away. I should be able to run on the 5.3L tune, knowing their will be some volume values I'll have to tweak later down the road.

I'm wondering if anyone has done a similar swap and had some tips as to what else I may need to pick up before I start. I don't have exhaust manifold gaskets, and I'm not sure how different they are (if they'll match up to my old exhaust). I'll probably swap the 5.3L ones onto the 6.0L before I drop it in, but wanted to know if I can reuse the gaskets (like you can on a Ford modular motor). If not, can I use high temp RTV? I've had great success using it on my all my Mustang exhaust parts, including headers and both turbos. I just don't know how well it works with stock exhaust manifolds.

Let me know if you guys think there is anything I absolutely need to have before I begin the swap.

Oh yeah, one of the fan blades on the 6.0L is broken. Can I still use it, or will it cause a vibration? If I can't use it, is it that hard to put the 5.3L fan on it?

Thanks in advance!

Jimbo1367

I wouldn't use the 6.0L fan if its broken. Asking for problems

Flapjack

I won't. I'll pull the fan off of the 5.3L and use it on the LQ4.

CattleAc

iTrader: (7)

I wouldn't even take the ex manifolds off...(unless you have to remove a broken bolt from the cyl head) They are the same as your 5.3. And yes I have reused the gaskets more than once on these.

Get some new gaskets for the exh flanges...should be good to go.

And what Jimbo1367 said...DO NOT use that fan with the blade missing. Your old 5.3 fan will work fine.

Flapjack

Thanks for the tip. I definitely can't stand when an exhaust flange leaks and you need to take it back apart...

Pretty slow-going last night. A friend and I worked a few hours and got the block pretty much exposed. I was dismayed to find that the A/C coils are built right into the radiator. On my Mustang, I've always been able to remove the radiator to make a lot of room for the engine to come out, without having to crack the A/C lines. Gonna try to get it out with the radiator in place...

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Flapjack

I'm having a hard time trying to figure out how to separate the engine from the tranny. I've disconnected the exhaust from the collectors, removed all the tranny bellhousing bolts, and removed the starter. I think I read somewhere that I have to disconnect the torque converter, but I can't for the life of me figure out how. Used to working on standards with a clutch....

rennat_2006

iTrader: (10)

You need to go in from where the starter bolts in and remove the 3 if i remember right flywheel to torque converter bolts. Obviously youll have to turn the engine over to get them to line up with where the starter usaully is.

Everything motor wise should be the same. I just did a 5.3l to lq9 6.0 swap in a 02 burban and the only thing i had to change was the oil pressure sending unit.

Flapjack

Yeah, I was missing that crucial little tidbit. Feeling like an idiot, lol.

Ended up getting the engine out, working lazily, drinking beer, etc... Both engines are outside, waiting to swap parts from the old to the new, but it's been pouring rain for the past few hours. Decided to call it quits as the weather isn't supposed to let up anytime soon. Probably gonna take tomorrow off and get it finished.

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Flapjack

I'm nearly done with the swap, thank God. I just have a few minor things like the intake, hoses, harnesses, to hook back up.

I have a few questions regarding selling the leftovers:

I'm trying to figure out what to do with the old engine, and the 6.0L intake and injectors.

- I figure I can easily take out the injectors and sell them for $100 or so (not sure what size they are).

- Not sure what the 6.0L intake is worth. It is identical to the 5.3L with the exception of the valve cover not having a PCV valve on it (can easily run an inline one).

- Should I sell the engine as-is? If so, how much would it be worth? Cylinders 1-7 are perfect, compression-wise. The compression in cylinder 8 is about 45psi less than all others.

- If I don't sell the engine alone, I should be able to sell the heads by themselves. They are in excellent condition.

- Are the stock exhaust manifolds and/or 6.0L flex plate worth anything?

Thoughts?

dvdswan

where are you located? I'll buy it as is if you are close to Seattle.

Flapjack

Too bad... I'm in Colorado. You can drive out and hang out for a day, though. I'll provide beer.

dvdswan

I just may do that in April next yr when I head to AZ. Beer seems to call my name very well.

Flapjack

Sounds like a plan. Of course, it'll probably be gone before then. I already have a Ford stock 5.4L mod motor in perfect shape... I just haven't marketed it really well. No matter how well I cover it up, the wifey still knows it's out there. :o)


BTW, does anyone know what this bracket might be?

Flapjack

Sorry for the lack of updates. We finished the truck Wednesday night after 1pm. I took it to work the rest of the week and had no mechanical problems, just a few error codes and poor performance.

The codes are:

P0151: O2 Sensor Circuit Low Voltage (Bank 2 Sensor 1)
P0332: Knock Sensor 2 Circuit Low Input (Bank 2)

My buddy hooked up the knock sensor while I worked on other things. He said there was only one place it would go, but I guess I'll have to double-check. On my Mustang, there are no less than 3 places the knock sensor can hook up. The other two are IMRC plates and O2 sensors, which if it's the same on a GM (all Bosch sensors?), swapped harnesses could explain both codes. I really doubt it, though. Gonna check for wire pinches and all that stuff, too.

As for performance, it's just a dog. I used the 5.3L injectors, but it is still a different engine. I have no idea how the GM strategy works, but I know that the Ford PCM would not run it this good. Still, it backfires when cold, has spotty acceleration (sometimes good, sometimes bad), etc... So I'm looking at tuning options now. I've pretty much decided to get tuner, as I would like to put a blower or turbo on it some day.

Flapjack

So I figured out what the problem was. When we put the intake back on, we didn't realize the knock sensor harness was laying to the side, not out of the back like it's supposed to. My buddy had no idea, and I was working on something else, so he just plugged it in as-is.

The pics are of what the harness looked like, lol. Luckily, the harness from my old engine was in good shape, so I reused that. The old knock sensors looked like ***, but I knew they worked just fine prior to pulling the engine, so I went ahead and put them in the 6.0L.

So far, everything is good. I drove it for two hours today without the light popping up. I'll make another 2hr trip tomorrow. If it doesn't come back up, I'll call it 'good'.

jonesjgqg

I wouldn't use the 6.0L fan if its broken.

Flapjack

Thanks, but that was handled a long time ago.