Head gasket build

[blueshift]

I'd do every rubber line under the hood (coolant, fuel, and hydraulic) and use spring clamps (like the factory did) except the few places where a worm clamp is appropriate. Even if you don't want to go that far, please do that 3" long coolant hose that runs over/behind the fan pully bracket. The one that returns the turbo coolant back to the bypass tube. The ones in the valley can be tackled later but that one is a tough cookie on its own.

I guarantee the turbo thermostat has enough crud in it that it's stuck open.

Your water pump looks like it might be newer than the truck. Your harnesses also look like they aren't shedding brittle loom like mine were, before I redid everything I could touch.

An updated oil cooler if you have heavy towing aspirations?

Not the OP, but currently in a similar situation, and I agree 100% (especially the bolded).

As I mentioned earlier, I'd already decided to do the soft fuel lines, as they looked pretty bad. Finally swapped them out last night, and WOW, they were awful. I swear I could almost see through the small 5/16" ones on the CP3. I think the inner liner was the only thing still intact. I was going to use the spring clamps, but the replacement hose I got (Shields Rubber 368, USCG approved stuff) was quite a bit stiffer and the spring clamps didn't seem to compress them much, so went with some good quality Ideal worm clamps.

Went ahead and did the coolant lines on the upper half of the motor as well. They didn't look terrible, but again, were quite soft and flexible compared to the new stuff I got. What's $40 more when I'm already $4k+ and 30 hours into it?

Didn't mention it in my post earlier, but I also rebuild the filter head. Again, what's another $20 while it's already off the truck? And based on how square-shaped all the round o-rings were, I couldn't believe it wasn't hemorrhaging fuel everywhere, especially under 7-8 psi from the lift pump.

Funny you mention the harness. Mine was in shambles, and getting worse every time I only looked at it. Almost just said 'eff it', but my OCD got the best of me. Pulled the engine harness off and completely reloomed it. Did the bundle coming out of the fuse box as well. Used the TechFlex F6 split braided. Quite a bit of work (tedious, too), but OMG, may be one of the most satisfying things I've ever done on a truck / car. It looks amazing.

Considered doing the water pump, too, as I know mine is original (260k miles). But it looks like draining the coolant is about the only common step with changing the injectors. Kinda like the OP, I've been piecemealing this project for a couple hours at a time for the last several weeks, and I'm ready to get it finished. So that'll be a job for another day.

Thanks for the advice, and a bit of reassurance that I'm not crazy for adding on all this extra time / money / work to this already big job. Hope the OP feels the same way.

 

[lb7resto]

First looks from last night:



Cylinder 8:


I didn't take pictures of the heads, but they were about as you'd expect after seeing this. The only thing I really took note of was a little bit of corrosion on most of the valves which would probably clean up fine, maybe leave some pitting behind. After seeing the heads it pushed me over the edge to the fleece heads. I really just hate the idea of messing with the cups and them causing me trouble in the future.

The water jacket in the block looks rough. We'll see how well that cruddy corrosion lying on top of cylinder 7 cleans up, fingers crossed. Other than just being dirty above the rings the cylinders looked good, I saw some vertical lines in #5 but it didn't look too bad, I'll get in there and see what that's about later.

 

[lb7resto]

My wire looms at the driver's fender are absolutely crumbled to dust. I do want to get some OE loom and fix the few spots where it's gone.

I do appreciate the notes about the coolant lines. I probably would have re-used everything that wasn't busted but I will replace them all. Rebuilding the filter head seems like a good idea too. I want to avoid the water pump for now, already enough scope creep happening here - I need to get this thing going.

 

[lb7resto]

I reckon my next step is block prep. What do you guys recommend?

 

[2004LB7]

I reckon my next step is block prep. What do you guys recommend?

To prep the block...

 

[TheBac]

You can use a straightedge to check that the block surface is flat. I have an adjustable carpenter square, and used the ruler portion of it.
I then very carefully cleaned the block surface with a piece of emery cloth wrapped around the same ruler.

Rebuild was in 2009, and engine has 70,000 miles since with no sealing issues.

 

[lb7resto]

To prep the block...

Well I've seen people say sand it and I've seen people say don't even touch it with a scotch brite. Manual says gasket scraper only which is what I'm inclined to.

I'm realizing now that even though I've built a few gassers I've only ever done one strictly head gasket job, and it was a parking lot rescue on a friend's jeep (went into deep water and I dared him so I figured I owed it to him), I don't even recall what I did to prep surfaces... nothing? So every other time I've done this before everything has been fresh machined.

 

[2004LB7]

Well I've seen people say sand it and I've seen people say don't even touch it with a scotch brite. Manual says gasket scraper only which is what I'm inclined to.

I'm realizing now that even though I've built a few gassers I've only ever done one strictly head gasket job, and it was a parking lot rescue on a friend's jeep (went into deep water and I dared him so I figured I owed it to him), I don't even recall what I did to prep surfaces... nothing? So every other time I've done this before everything has been fresh machined.

I've had good luck using a flat block of aluminum or steel with a piece of sandpaper stuck to one side. Clean up the whole surface then like Tom mentioned, use a good straight edge and check for flatness. I like to use a flashlight behind the edge and look for light coming through. Sand the high spots until you are flat. Don't forget to stuff rags in the cylinders and clean them up thoroughly. You can tape them off too to keep the grip from getting down between the pistons and cylinder

There is many options and opinions on the subject so don't take it as the only way.

 

[PureHybrid]

Don't use a "Roloc wheel" or scotchbrite disc, I like using the green bristle disks. They're basically plastic fingers. You could use a scotchbrite like the gray ultra fine, but I'd do it by hand. Honestly unless there's some crud that a general wiping won't remove, just use a lint free rag and hit it with some alcohol

 

[TheBac]

You dont need to overthink this. Its exactly like building a gasser, just the parts are larger.

 

[lb7resto]

After working it a little I'm finding there to be some pretty tough corrosion right where the fire ring sits, it will only come off with a metal scraper and then isn't smooth. I think I'm going to have to use sandpaper.

Really what brought me in here today was to ask if I should get the PPE cast iron cupless heads instead of the fleece aluminum for this.

Also as I'm getting my shopping cart together I wanted to ask about dmaxstore in general and if their injector pressure lines were good or if I should stick with GM.

 

[1FastBrick]

You might want to talk with Brad @Bdsankey in here. He is a form sponsor as well his family has a shop.

 

[N2BRK]

After working it a little I'm finding there to be some pretty tough corrosion right where the fire ring sits, it will only come off with a metal scraper and then isn't smooth. I think I'm going to have to use sandpaper.

Really what brought me in here today was to ask if I should get the PPE cast iron cupless heads instead of the fleece aluminum for this.

Also as I'm getting my shopping cart together I wanted to ask about dmaxstore in general and if their injector pressure lines were good or if I should stick with GM.

I asked about those heads here not long ago; no love to be found. Fleece all the way, from every reply that I was given in public and in private.

 

[Bdsankey]

Personally I would go with Fleece > PPE. They're a better value and do the same job.

 

[DAVe3283]

I am running the Fleece heads on my LB7 swapped Suburban, and have no complaints or regrets. Not having to ever worry about or touch injector cups ever again is nice.

 

[Bdsankey]

I am running the Fleece heads on my LB7 swapped Suburban, and have no complaints or regrets. Not having to ever worry about or touch injector cups ever again is nice.

They are our go to if there is a damaged head or a customer doesn't have time to wait for a machine shop.

 

[lb7resto]

I need to test the connector and wiring for my FPR. Looking at the connector diagrams in ALLDATA, it looks like I need to test the connector to ECM C2 Pins 42 and 77. Can anyone confirm that? It seems straightforward but I feel like I always get automotive electronics wrong and end up chasing the wrong thing.

 

[2004LB7]

If this is for the 04 in your sig then here is the official GM pinouts. Connector #2 pins 42 & 77 look correct