2008 Tahoe LMG Engine Swap

[Cludington22s]

Hey everyone,
New to this group, but have used it in the past to find info. I have a 2008 Tahoe with the LMG engine. I keep having engine issues with the AFM and what not. I’ve owned older versions of this motor pre-AFM and have just noticed to get more life out of them. I guess what my question is swapping out the LMG with something that’s more bulletproof for just general use and longevity. What engine do you think would be the easiest and most cost-efficient I don’t mind spending a little bit of money to do this as long as I’m getting more life out of said vehicle and can do most of it myself. Thank you!

 

[Marky Dissod]

Willing to spend a bit more money to get even better bang-for-the-buck? Find an L76 (truck version) / LY6 / L96 / LC8 6.0L.
GM 6.0L V8s are famous for durability and longevity above and beyond the lesser 5.3L variants when maintained assertively.

If you want more power and torque, better fuel economy, and quicker throttle response (and are willing to get tuned),
install your LMG's heads on top of the L76t / LY6 / L96 / LC8.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

Or, you could go with a remanufactured 6.2L L92 motor (no AFM) for under $5000.

 

[Cludington22s]

This is Frosty, 2008 LTZ Tahoe, have had it for about a year. Rebuilt trans right after I got it, pretty rust free and interior is in good shape. I really like the style of these trucks so I’d like to get some good years out of it !

 

[Cludington22s]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

Or, you could go with a remanufactured 6.2L L92 motor (no AFM) for under $5000.

So going with the L92 I would Just need a tune in theory, everything else should bolt and plug up ?

 

[Marky Dissod]

So going with the L92 ...

or any of the 6.0L engines I mentioned, depending on whatever deal manages to appeal to your wallet best at that time ...

I would just need a tune in theory, everything else should bolt and plug up?

Every GM V8 between 99 & 13, between 4.8L & 7.0L, is physically interchangeable with any other.
Just take your old one out, and put the newer one in its place.

 

[j91z28d1]

it is easier if you stay with the crank trigger tooth count your year ecm is looking for thou. what is it? older 24 or newer 58? something like that. the cam seosor is believe there's 2 or 3 different setups but all can be adjusted for with either a small jumper harness or in the tune?

the 6.0 seems to be the most reliable combo if you want to run 87 octane. if you're good with always running 93 the 6.2 will get you a little more hp. but you'll have to cam swap to to get rid of afm. vvt seems pretty reliable, but does require a timing chain tensioner setup that can fail, compareed to a non vvt stright chain that shouldn't really ever fail.

 

[Joseph Garcia]

So going with the L92 I would Just need a tune in theory, everything else should bolt and plug up ?

Yes, it should be an easy swap. You will need a tune, and that can be accomplished. As mentioned above, the L92 needs to run on 91 octane minimum to keep the motor happy, and to give you all of those 405 HP.

The L92 does not have AFM, so no internal parts swapping is needed.

 

[Cludington22s]

Perfect ! Thanks for the info!!

 

[roc1967]

or any of the 6.0L engines I mentioned, depending on whatever deal manages to appeal to your wallet best at that time ...

Every GM V8 between 99 & 13, between 4.8L & 7.0L, is physically interchangeable with any other.
Just take your old one out, and put the newer one in its place.

Physical interchangeably is important, but what about Controls/Datalink compatibility with transmission, ABS, body controllers?

 

[Marky Dissod]

Physical interchangeably is important, but
what about Controls/Datalink compatibility with transmission, ABS, body controllers?

Only difference between any GM V8 vs any other GM V8 (of the same generation), are tune-able variables.
This is why people who didn't know better would say 'grab the pcm / ecm from the engine you bought',
not yet knowing that even the meager differences are easily handled by a competent tuner.

If you feel froggy, you can even adjust for the differences between a Gen3 vs a Gen4, with a lil patience.
I'm dreaming of upgrading to an L77 someday, but I'll settle for ANY GM 6.0L V8.

This page will help you keep track of the differences; they are minor details, not insurmountable obstacles:

The Definitive Guide to LS Engine Specs and LS Engine Upgrades

We put everything you need to know about the Gen. III & Gen. IV LS engine family in 1 spot—from cam specs to upgrades & everything in between.

www.onallcylinders.com

Oh: compatibility with those things you mentioned is 100%.

 

[j91z28d1]

I remember the grab the ecm and all when you swap days. don't miss that.. these days the ecm has to talk to the rest of the truck so as said, it's much eaiser tune your current ecm timing and fuel maps to the new engine than to reflash a different ecm to talk to the rest of the truck. you can literally download the tune file from the truck you got the swap engine from, most are already online. open a compare in hptuners and just copy and paste the major stuff over to get it running and then fine tune as needed for any mods you did.

it is easier if you sick with swaping Gen 3 into Gen 3 and Gen 4 into Gen 4 because of the different crank tooth count.

 

[petethepug]

Happy Thanksgiving Cludington. The L92 or L9H clone from Jasper is the boring 403hp complacency you’re looking for.

Yes, the power is great but it’s capabilities to move the truck around without lifting a finger is it’s best attribute. It never works that hard.

Nice truck and you’ve got the 4SP trans that’s not a good pair to the 6.2 though. The shortcut around all this is to find an 07-14 Chevy, Caddy GMC truck / SUV with a 6L80 & 6.2L to yank out as a pair.

 

[Cludington22s]

Happy Thanksgiving Cludington. The L92 or L9H clone from Jasper is the boring 403hp complacency you’re looking for.

Yes, the power is great but it’s capabilities to move the truck around without lifting a finger is it’s best attribute. It never works that hard.

Nice truck and you’ve got the 4SP trans that’s not a good pair to the 6.2 though. The shortcut around all this is to find an 07-14 Chevy, Caddy GMC truck / SUV with a 6L80 & 6.2L to yank out as a pair.

I just rebuilt this trans about a year ago so I’m definitely gonna have to stick with that for at least a little while, but I did order an l92 out of an 07 Denali GMC, I’ll freshen it up a bit and throw it in.

 

[07burban88]

so to put a gen3 engine into a 07 to 14 gen4, the way I'm planning it, you would have to swap the crank as the gen4 has a 58x reluctor and the gen3 is 24x and front timing cover as the cam sensor is on front cover. and of course, mount the knock sensors to the sides of block. I'm not 100 percent on crank though, just easiest way I can see to fix the reluctor wheel issue

 

[swathdiver]

so to put a gen3 engine into a 07 to 14 gen4, the way I'm planning it, you would have to swap the crank as the gen4 has a 58x reluctor and the gen3 is 24x and front timing cover as the cam sensor is on front cover. and of course, mount the knock sensors to the sides of block. I'm not 100 percent on crank though, just easiest way I can see to fix the reluctor wheel issue

In addition, the knock sensors and the cam and or crank sensor are in different locations as well. It's less expensive and less aggravating to stick with the same generation engines.

 

[Reebok59]

No one has mentioned the vvt issue yet. The 2007 and 2008 LMG engine is non-vvt. And therefore has a non-vvt ECM. I am in the same boat with a 2008 Suburban with an LMG and planning a swap for when the day comes. However, I am leaning towards the 6.0 (LY6 or L96). As I understand it, all Gen 4 6.0s and 6.2s are vvt. So I would assume that if swapping with LY6, L96, or L92, it would require either vvt-delete or changing out the ECM. Correct?

 

[Marky Dissod]

so to put a gen3 engine into a 07 to 14 gen4, you'd have to swap the crank as the gen4 has a 58x reluctor and the gen3 is 24x

There's a way to do this without swapping an entire crank - but if you want to address the crank bearings, then you may as well swap the crank, I guess.

and front timing cover as the cam sensor is on front cover.

There are other ways around this too.

and of course, mount the knock sensors to the sides of block.

Not sure precisely how, but Gen4 or Gen3 knock sensors can be mounted to the side of a Gen3 block.

 

[Marky Dissod]

No one has mentioned the vvt issue yet. 07 & 08 LMG engine is non-vvt, therefore has a non-vvt ECM.
I am in the same boat with a 08 Suburban with LMG, planning a swap for when the day comes.

It either has a non-VVT ECM (unlikely but possible),
OR
it has a non-VVT TUNE (GM OE) in an ecm that COULD support VVT - but it was not turned on, as in PRE-disabled (GM-pre-disabled L92's V4 mode)
OR
it has a non-VVT pcm. Does it have a 4L60E or a 6L80E? 4L60E LIKELY uses a pcm, 6L80E definitely uses an ecm & a tcm.

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add your VIN after the equal sign, that link will describe your vehicle's RPOs, and will help you determine what you're supposed to buy for your vehicle
(but buy from another website, GMPartsGiant overcharges)

However, I am leaning towards the 6.0L (LY6 or L96). As I understand it, all Gen 4 6.0L and 6.2L are VVT.

They both are.

So I would assume that if swapping with LY6, L96, or L92, it would require either vvt-delete or changing out the ECM. Correct?

Incorrect. Just disable VVT in the ecm - that is if the vehicle uses an ecm capable of supporting VVT.
If the Pcm (or the ecm's operating system) cannot support VVT, it is already effectively disabled - just like I can't use my 3rd eye for telekinesis.
Once VVT is disabled, you then have the option of physically deleting it of course (recommended, of course),
or, it can simply be limited (not sure which is cheaper, physically limiting VVT, or deleting it).

 

[Cludington22s]

It either has a non-VVT ECM (unlikely but possible),
OR
it has a non-VVT TUNE (GM OE) in an ecm that COULD support VVT - but it was not turned on, as in PRE-disabled (GM-pre-disabled L92's V4 mode)
OR
it has a non-VVT pcm. Does it have a 4L60E or a 6L80E? 4L60E LIKELY uses a pcm, 6L80E definitely uses an ecm & a tcm.

Free GM Vin Decoder | GMPartsGiant

Free GM VIN Decoder - Do a VIN lookup to acquire specific car information. Ordering exact-fit parts has never been this smooth and hassle-free on GMPartsGiant!

www.gmpartsgiant.com

add your VIN after the equal sign, that link will describe your vehicle's RPOs, and will help you determine what you're supposed to buy for your vehicle
(but buy from another website, GMPartsGiant overcharges)

They both are.

Incorrect. Just disable VVT in the ecm - that is if the vehicle uses an ecm capable of supporting VVT.
If the Pcm (or the ecm's operating system) cannot support VVT, it is already effectively disabled - just like I can't use my 3rd eye for telekinesis.
Once VVT is disabled, you then have the option of physically deleting it of course (recommended, of course),
or, it can simply be limited (not sure which is cheaper, physically limiting VVT, or deleting it).

It either has a non-VVT ECM (unlikely but possible),
OR
it has a non-VVT TUNE (GM OE) in an ecm that COULD support VVT - but it was not turned on, as in PRE-disabled (GM-pre-disabled L92's V4 mode)
OR
it has a non-VVT pcm. Does it have a 4L60E or a 6L80E? 4L60E LIKELY uses a pcm, 6L80E definitely uses an ecm & a tcm.

Free GM Vin Decoder | GMPartsGiant

Free GM VIN Decoder - Do a VIN lookup to acquire specific car information. Ordering exact-fit parts has never been this smooth and hassle-free on GMPartsGiant!

www.gmpartsgiant.com

add your VIN after the equal sign, that link will describe your vehicle's RPOs, and will help you determine what you're supposed to buy for your vehicle
(but buy from another website, GMPartsGiant overcharges)

They both are.

Incorrect. Just disable VVT in the ecm - that is if the vehicle uses an ecm capable of supporting VVT.
If the Pcm (or the ecm's operating system) cannot support VVT, it is already effectively disabled - just like I can't use my 3rd eye for telekinesis.
Once VVT is disabled, you then have the option of physically deleting it of course (recommended, of course),
or, it can simply be limited (not sure which is cheaper, physically limiting VVT, or deleting it).

Update* have the L 92 on the stand almost ready to go in just waiting on a few more little detailed parts. Just wanna have everything ready at the time of swap, this motor has the VVT option, but the Tahoe (Frosty) does not, assuming the ECM doesn’t support it since it didn’t come with that vehicle stock can I just leave this in here? I actually ordered a new VVT sensor so I’ll put that one in just so it looks clean, but will it affect anything if I just leave it without deleting it?