Lq4 2004 what to do before dropping in

[Amaster]

We're saving the 3/4 ton after all, got a used engine and transmission and tc for a hell of steel. Now I'm just wondering what all to do before we drop this thing in. I was thinking rear main, knock sensors, injectors, valve covers water pump lifters. Anything else?

 

[justirv]

We're saving the 3/4 ton after all, got a used engine and transmission and tc for a hell of steel. Now I'm just wondering what all to do before we drop this thing in. I was thinking rear main, knock sensors, injectors, valve covers water pump lifters. Anything else?

While you're doing the rear main, suggest adding billet oil barbell, from Sac City or comparable, and also their rear main centering tool, if you don't have one. Your list looks good, might as well add the oil pressure sensor. I always look at accessibility, now vs. later.

 

[Marky Dissod]

We're saving the 3/4 ton after all, got a used engine and transmission and tc for a hell of steal.
Now I'm just wondering what all to do before we drop this thing in.
I was thinking rear main, knock sensors, injectors, valve covers water pump lifters. Anything else?

Use heads from any ol' 4.8L / 5.3L for an scr bump-up. Cheap bang-for-the-buck performance mod,
although a tune will be required for best results.

Convert to Gen4-style knock sensors so you won't need to remove intake manifold to maintain/replace them next time.

 

[Mudsport96]

Unless you are going to be running premium every fill up stay with stock heads. You will end up in the neighborhood of 10.7:1 compression going that route. I am going to assume that this is a daily that you aren't looking to race? If you were to change heads 799s would get closer to 10:1 if you had a really good tune you would probably be alright. But if you tow alot, you would have to pull timing to make it live, and at that point you negate the additional power the compression gives you.

Do an oil pump, or at least shim the pressure relief spring. Do the pick up oring. But the rest of the list looks okay. Not sure about messing with the barbell, my Silverado has 423k on it with all stock internals except pick up oring.

 

[Marky Dissod]

Unless you are going to be running premium every fill up stay with stock heads.
You will end up in the neighborhood of 10.7:1 compression going that route.

So how'd the LFA / LZ1, both with 10.7:1 scr, get away with using 87 octane?

 

[Mudsport96]

So how'd the LFA / LZ1, both with 10.7:1 scr, get away with using 87 octane?

TUNE and computing power of the E38/E67 ecm was miles ahead of the P59 that the OPs vehicle has. Yes they can run on 87, my old man's '16 runs good on it. It runs WAAAYYY better on e85. Not because e85 "makes" more power. But because of the octane it has the computer puts more timing into the engine and it can recover the power LOST by running an inferior octane fuel. Heck even the old p59 setup adds 5 degrees of timing for e85, I dont have the ability yo see the newer pcm timing, but with a faster processor, you can figure it is at least the same as the older unit.
Im not saying he can't do it. I would just not recommend it unless a very good tuner can be found.

 

[strutaeng]

Keep the original injectors. Nothing wrong with them and probably more reliable than aftermarket ones.
Everything else sounds good otherwise.

What is this going into?

 

[noodlesandsam2]

Did not see oil pressure switch above, but I could have missed that. Oil pump pickup screen check and O rings for sure.

 

[Amaster]

Did not see oil pressure switch above, but I could have missed that. Oil pump pickup screen check and O rings for sure.

That was something already on my list too. Due to the fact i know they can have issues.

Keep the original injectors. Nothing wrong with them and probably more reliable than aftermarket ones.
Everything else sounds good otherwise.

What is this going into?

I just figured since the intake is off would be good. I was just looking at stock or maybe late model 6.0 injectors. This is going in a 04 yukon xl 3/4 ton.
Out of curiosity how do you convert over too gen 4 knock sensors?

 

[strutaeng]

LQ4 is a Gen III, so it will be a plug 'n play for a 04 Yukon XL 2500.

Gen IV knock sensors...in a Gen III engine? Never heard of this.

You can use a Gen IV block in a Gen III vehicle though. You drill/ream the existing threads on the side of the engine for the Gen III sensors. I have an engine in my engine stand I did this to.

 

[Marky Dissod]

Gen IV knock sensors ... in a Gen III engine? Never heard of this.

It's not actually using Gen4 knock sensors on a Gen3, it's about MOVING the Gen3 sensors to the Gen4 location,
so you'll never need to remove the intake manifold to replace them ever again.
The pcm you use will determine the knock sensors it expects.

Using the Gen4 5.3L heads on an LQ4 will result in less scr than using Gen3 4.8L / 5.3L heads,
but will still improve performance over LQ4 heads.

 

[Amaster]

Well I'll just replace them in the stock location. I'll be using the stock computer that's already in the truck so, I don't think we'll change over the heads either this is toter so we won't be racing down the strip. We may make it a awesome 4 wheeler but first things first we got to get it back here.

 

[Amaster]

Whelp update we got it back here and dropped it off at the shop I'll let you guys know when it's alive.