Advice for LLY Head Gasket replacement

tenderdurden

tenderdurden

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Mar 18, 2020
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I'll try to keep this short. I do a lot of work with addicts in recovery, and because of helping a family get their kid into rehab, they gave me this 2005 LLY for WAY less than it's worth. However, it does need to have the head gaskets replaced.

The truck still ran with great power before I started on this (except spitting out all the coolant.) It has had over $6,500 in maintenance done in 2019, new transfer case, new transmission, $1,500 in new tires, and it has clearly been well-loved in the past. I'd rather not spend $6,000 to get the heads done at the shop. I've spent DAYS researching and watching how it is done. If I do put extra money in, I'd rather learn about my truck and have a decent tool set to show for the expense.

Can someone who has only replaced fuel pumps, alternators, and other basics tackle a head gasket job on an LLY or will I make it all worse? Do I add the EGR block while I'm at it? How about the turbo intake that I've heard are bad on these LLY's? It has a Bully Dog performance system, so should I do studs? Here's how far I've gotten:
 

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Bdsankey

Bdsankey

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If you take your time and understand it won't be a 2 day job then I think you can tackle it. Don't rush, don't skip any steps etc and you should be fine if you are pretty decent at turning wrenches. As for parts, you will need all the same parts either way, what changes is if you decided to do studs/egr while you're in there.


You need grade c head gaskets (you could use a different thickness based of protrusion but the grade C is a little easier as it will work on any factory block that hasn't been decked), an upper gasket kit, and head fasteners of your choice. You can either use factory torque to yield (TTY) bolts or ARP studs. The cost difference is ~$450 to get studs vs TTY bolts. You also will NEED to have the heads checked for flatness and overall health (guides/seats/etc).


My kit is ~$508 with TTY and ~$960 with ARP studs. Both prices are shipped and use only Mahle/Victor Reinz gaskets with wave stopper head gaskets as opposed to the GM gold gasket. In my opinion, an EGR delete isn't a bad idea if your state/area doesn't do testing. The early systems were failure prone and nowhere near as refined as the newer systems. My truck had a ton of gunk built up in the intake tract from the EGR and PCV when I tore it down to start the first stage of my build.


As for the mouthpiece, I would definitely replace it as they are very restrictive. You can use an S&B, AFE, HSP, WCFab, or even a factory LBZ/LMM mouthpiece with a few little changes to the factory intake. Lastly, while you're in there, I would recommend replacing the cover on the rear engine housing that seals the cooling system. Note, this is my personal opinion and not 100% mandatory but I have been bitten more than once by that cover warping and leaking so I make it a point to change every one I can while I'm that far into the job to avoid that failure again. The billet covers are ~$65 and are sealed with an o-ring as opposed to the factory flimsy stamped cover and gasket.
 
Chevy1925

Chevy1925

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Oct 21, 2009
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Key isnt you being able to do it, its having a competent machine shop by you that knows how to check those heads for cracks, how much they can deck the head before needing to recess the valves more, and what spring seat pressure the valve springs should be checked and set to.

its all nuts and bolts for you, just take your time and take pics of how you pulled it apart. organize all the bolts in little sandwich baggies and label them where they go. wiring harness is hard to plug into the wrong stuff as they are keyed for specific plugs
 
Bdsankey

Bdsankey

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Chevy1925 said:
Key isnt you being able to do it, its having a competent machine shop by you that knows how to check those heads for cracks, how much they can deck the head before needing to recess the valves more, and what spring seat pressure the valve springs should be checked and set to.

its all nuts and bolts for you, just take your time and take pics of how you pulled it apart. organize all the bolts in little sandwich baggies and label them where they go. wiring harness is hard to plug into the wrong stuff as they are keyed for specific plugs
Click to expand...

Sandwich bags are the most underrated items when it comes to repairing these trucks. It allows for easy labeling and makes it much easier to put back together instead of just grabbing from a big box of bolts.
 
jedenbeck

jedenbeck

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Aug 11, 2015
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I did my first set with pretty much no knowledge of what I was getting into. Anyone with mechanical ability’s can do it if they are careful and pay attention. I labeled everything I took off and parts went in bags labeled etc. it will take you a few days to do it. Clean and organized work area is a must. Most aggravating part to me was adjusting the valves back. I did everything my self I had zero help.
 
NevadaLLY

NevadaLLY

Adam B
Feb 24, 2019
311
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28
Reno, NV
I did this build myself as well and a few tips I recommend:
Set up a large table or two, so you can lay out all the parts. I used blue masking tape and a marker to stick on the table and write down what it was and where it came from. (Baggies got too cumbersome). Next, I used a silver sharpie to label every electrical connection and any disconnects I made. I drew the mark directly on the parts so when going back in, match 1-1, 2-2, A-A, B-B, etc. Using this method, I did the whole job and not one issue. Started in first crank and has been running perfectly the last 7 years. I also did not do anything with the heads other than clean up (very carefully) any residue or debris from the prior gasket. I installed ARP studs and I’d recommend it for an LLY. TTY are single use and if you have to get back in there later, you’ll re-spend the money on hardware.
 
Chevy1925

Chevy1925

don't know sh!t about IFS
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Oct 21, 2009
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techperry said:
So using the wave stopper that are listed for overbore and decked blocks on everything?
Click to expand...



I suggest just picking up Grade C victor reinz or mahle gaskets. These will have a compressed thickness of .0394 to .0433 (most list them as 1.05mm thick)

All the ones I’ve gotten have been a “wave stopper”, even the A’s I have sitting in my shop right now. Even if they are not, I wouldn’t worry. They are still better than the gold acdelco
 
Chevy1925

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,123
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Phoenix Az
all the stock and aftermarket gaskets fit a .040 bore. the grade D was made for a decked block but factory pistons. this way piston protrusion does not hit the heads when you take .005 to .010 off the block, its a much thicker gasket.

they call it an "over bored, decked block gasket" but its really just for a decked block if you are using factory pistons and NOT cutting the tops of the pistons the same amount as the block.
 
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