LML swap difficulty

Powellbr

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Nov 17, 2015
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Hi all, so I got wondering as I was reading and finding parts for my project and got wondering how hard it would be IYO to do an LML swap into my '93 K1500, this won't be the only thing done though to it, as I will also be doing a 14 bolt swap under the rear and a D60 under the front. So where am I going wrong on this? Please let me know where I'm going wrong with this as I'm probably going wrong somewhere with this, whether it's I forgot something or something like the frame is gonna do something spectacular and shit the bed or something. Thanks for the input as it will be greatly appreciated.
 

CarolinaHD

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Feb 8, 2011
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Frame is gonna be too weak. Ferminator will hopefully chime in with all the other little details.
 

Powellbr

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Nov 17, 2015
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So I'll elaborate a little on this if it'll help. I'm not going to be doing any things like the EGR cooler or the PCV system, although I may do a crankcase breather, and I'll be using the Banks Big Hoss intake manifold, idk if I'll do A/C on my truck, and it's gonna be twin turbo'd 'cause I'm hoping around 800 to 1000 horsepower & roughly as much torque, the dual fueler kit from H&S with twin CP3s, and either Banks or PPE exhaust manifolds
 

Powellbr

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Nov 17, 2015
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Any reason you're set on the lml?

Sent from my SM-N910V using Tapatalk

Idk actually if I have a reason chose the LML for this or not, once I have all the parts for the engine and that found I may look and see if the older versions of the Duramax would be less expensive and I'd be able to get away with some stuff that I couldn't with the LML, for a while I did have an idea to use an LLY as the heart for the swap, dunno why I went back to LML
 

Powellbr

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Nov 17, 2015
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Ben Tyler from BT Diesel Works will be the man to get your wire harness conversion from.

How will some of the gauges like the tach, speedo, and fuel level gauge with the swap from a gas fed 5.7L to a diesel? Just some things that I'd be worried about
 

Awenta

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Sep 28, 2014
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Yes you'll need to strengthen the frame. Alot.

So I'll elaborate a little on this if it'll help. I'm not going to be doing any things like the EGR cooler or the PCV system, although I may do a crankcase breather, and I'll be using the Banks Big Hoss intake manifold, idk if I'll do A/C on my truck, and it's gonna be twin turbo'd 'cause I'm hoping around 800 to 1000 horsepower & roughly as much torque, the dual fueler kit from H&S with twin CP3s, and either Banks or PPE exhaust manifolds

The banks is a waste of money. 1000 hp is a serious goal and you'll be making a ton more tq than that by then. What are your intentions with this truck? Built Trans and max effort in a platform this light would be a blast.

Idk actually if I have a reason chose the LML for this or not, once I have all the parts for the engine and that found I may look and see if the older versions of the Duramax would be less expensive and I'd be able to get away with some stuff that I couldn't with the LML, for a while I did have an idea to use an LLY as the heart for the swap, dunno why I went back to LML

A lly should net you much less headaches.

Sent from my SM-N910V using Tapatalk
 

THEFERMANATOR

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The lml and lat lmm's have some issues I believe regarding starting in swaps. Theres a thread here somewhere where Ben and kidturbo were talking about building a gateway to allow this kind of swap to occur. I would DEFINATELY go with a newer frame rather than trying to beef up yours for that kind of power goal. Thes gmt-400 frames are NOT tbat strong. Mines a 2500, and I've rippled the framerails some from the leaf springs forward about 2 feet. I would stick with an lbz or older just for simplicity sake imho. The speedo can be made to work, you can use a ls tach adapter to run your gasser tach, you can adapt in the stock oil pressure sender(and if you do use the stock 3 wire sender, you can use it to trigger your lift pump), and you can use the 3 wire coolant temp sensor to run your stock temp gauge. Leave the fuel gauge as is and thats all good there. When you go to the lmm/lml, you run into issues where so much in the truck is activated via the data bus whereas the lb7, lly, and lbz still were mostly hard wired.
 

duratothemax

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Aug 28, 2006
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I really dont recommend doing LML for standalone. You have to keep the BCM and stuff wired up, and the harness ends up being twice as expensive, complicated, and bulky.
 

Powellbr

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Nov 17, 2015
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I would DEFINATELY go with a newer frame rather than trying to beef up yours for that kind of power goal. Thes gmt-400 frames are NOT tbat strong. Mines a 2500, and I've rippled the framerails some from the leaf springs forward about 2 feet.

How would the frame from a 3500 hold up? I'm also not gonna go with leaf springs in the suspension, I'm gonna be using a triangulated 4-link system with coilovers on both ends and possibly a set of additional airbags in the rear to help the bed stay level when I'm hauling loads or towing
 

THEFERMANATOR

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How would the frame from a 3500 hold up? I'm also not gonna go with leaf springs in the suspension, I'm gonna be using a triangulated 4-link system with coilovers on both ends and possibly a set of additional airbags in the rear to help the bed stay level when I'm hauling loads or towing
The 3500 frame isn't much beefier. These early trucks just were not up to the torque that the DURAMAX can produce. If your going to do it, be prepared to plate and box the frame to hold it. Or go with a frame from a newer truck as they are night and day different.
 

Powellbr

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Nov 17, 2015
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So I was looking at the engine bay on my truck and physically how does the 6.6 compare to the 5.7? From what I'm seeing the block comes to where the front of the accessory drive on my 5.7 and the heads are about an inch to inch and half wider on each side than the 5.7 heads. Does anyone know for sure on this? Am I just worrying too much about it?
 

THEFERMANATOR

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Depends on which gen engine, but the lb7 is a good 8-9 inches taller, and probably at least that much wider. The duramax has the same 90 degree v, but the v just keeps going up alot higher. Also it is a good 3-4 inches wider at the oil pan level than a 5.7l.
 

Powellbr

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Nov 17, 2015
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So i was thinking with I don't rememmber who mentioned it but someone in here mentioned I would have to keep the BCM to get the LMM or the LML to run, what if I ran the OS off the LLY or LBZ modules on the modules on the LMM or the LML? Or could I run things the block or other hard parts off the LML on the LLY? The reason I ask is from what I've read an heard the block that's used in the LML is the strongest block for the Duramax to date, if I'm wrong please correct me.
 

DIESELMAFIAPER.LB7

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What you just said will not work in anyway shape or form......

Use a lly or lbz engine.

The lml block is stronger but I wouldn't worry about using any other block. The lml has some Suttle differences on the block from previous generations like where the oil feed and drain are a different coolant passage on the rear cover ect ect nothing major.

For simplicity just use a lly or lbz and save your self tons of time and grief
 

IdahoRob

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LBZ/LMM is the best for swaps IMO. Stand alone and you don't have to worry about the FICM extra wiring and plumbing of the LLY.
 

THEFERMANATOR

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LBZ/LMM is the best for swaps IMO. Stand alone and you don't have to worry about the FICM extra wiring and plumbing of the LLY.
I'm biased, but I still like the simplicity of my early LB7. And the fact it's wiring color code matched up to my 95 BURB's also helped. Made integrating the wiring ALOT easier to do. The FICM is no problem since it is all part of the engine harness to begin with, so no extra harness's needed.