Difference between G8 L76 and Vortec Truck L76 engines

[majesticix]

Anyone know the differences between these two engines? I know the intake is different, but what about the heads, VVT, weight, etc...? I know the numbers put the Vortec at 367/375 HP/TQ.

Reason I ask if you haven't followed my previous thread is I'm thinking they are putting this engine in my car as a replacement. They had to order some parts to get this engine to fit into my car (oil pan, dipstick). Dealer told me the motor was the same when I asked if this was an L76. I just would like to be informed of any differences and make sure I am not getting inferior parts or added weight.

I'm hoping this is just a shortblock swap and they will use my intake/heads (couldn't use my oil pan cause it had a hole in it).

Thanks for any help you can provide.

[norm8332]

From what I read the truck one has VVT while the G8's doesn't.

[norm8332]

Be sure to read the DOC attachment.

[johnbell2]

Looks like there's hope if they use a Suburban L76?

[p71]

I am betting on it not working and them having more lick with an LS2...

[stonebreaker]

The truck heads use the smaller intake valve size.

[13 QTR]

Pretty positive the truck one is a iron block....so more weight.

[GRRRR8]

The truck is an iron block with VVT, so I doubt they are using a truck motor.

[sales@spencershids.com]

Be sure to read the DOC attachment.

according to the attatchment, it is an iron block. I wouldnt worry too much about it as long as your getting it done at a dealership. We have to swap oil pans ALL the time on new motors. The oil pan is the only difference between many engines. I have even gotten an Aveo motor and had to swap the flex plate off of that because it was different. Dont stress what they are doing until they are done. Most dealership techs are plenty competent enough to realize that if the one coming out is aluminum block, the one going in should be as well.

[ChipC]

Like was said, I am sure the techs will put in the correct engine. I would point out though that GM Powertrain specs for 2007, 2008, 2009 all indicate that the Truck L76 is aluminum and not iron. The previous gen 6.0L truck motors were iron. Here is the 2009 truck list:

http://media.gm.com/us/powertrain/en/product_services/2009/09truck.htm

Chip

[ChipC]

according to the attatchment, it is an iron block.

Actually, the article states the LY6 is iron and the Truck L76 is aluminum. I had to read it a couple of times to get it right myself.

"The cast-iron block Vortec 6.0L (RPO LY6) was developed for heavy-duty applications, such as the all-new Chevy Silverado and GMC Sierra 2500 HDs. The LY6 has undergone the most rigorous lab- and road-testing process in small-block history. It’s validated to achieve 200,000 miles of operation in typical applications. The aluminum-block 6.0L was developed for maximum towing capability in vehicles like the Chevy Suburban. Its Active Fuel Management cylinder-deactivation technology improves fuel-economy when the trailer is empty or left behind."

Chip

[Crazy Paul]

The Vortec 6.0L V-8 VVT ( L76 ) is a cast aluminum block V-8 with GM’s industry leading Active Fuel Management (A.F.M.) technology. The 6.0L also features industry first cam-in-block variable valve timing. For 2009, the Vortec 6.0L V-8 VVT (L76), is found in the Chevrolet Avalanche, Silverado and Suburban, and the GMC Sierra and Yukon XL models.


The new Vortec 6.0L is offered with either a conventional cast-iron (LY6) or an aluminum engine block (L76), giving customers a choice and allowing technology appropriate to the application. The lighter aluminum block allows vehicle engineers more latitude in tailoring weight distribution, and can mean a slight improvement in fuel economy. The Gen IV aluminum block is cast from A356-T6 alloy. With cast-in iron cylinder liners, It weighs roughly 100 lbs. less than a comparable cast-iron engine block.


Variable Valve Timing
The Gen IV Vortec 6.0Ls bring GM Powertrain’s industry exclusive cam-in-block variable valve timing (VVT), or cam phasing, to the small block V-8.

The Vortec 6.0L’s dual-equal cam phaser adjusts camshaft timing at the same rate for both intake and exhaust valves. A vane-type phaser is installed on the cam sprocket to turn the camshaft relative to the sprocket, thereby adjusting the timing of both intake and exhaust valve operation.


http://mrpburke.com/fileupload/uploads/09l76vortec.jpg


http://mrpburke.com/fileupload/uploads/08_l76_g8.jpg


Externally:
Oilpan,Intake Manifold, Balancer, Waterpump, All front driven accessories are different.

[majesticix]

Very good info. From the picture above, there appears to be a significant difference visually anyway. I'll find out Monday what exactly they put in there and start asking questions.

[Crazy Paul]

Internal differences.

Possible different compression ratio, depending if you believe GM media online.
Different VVT pistons with valve reliefs.
VVT camshaft gundrilled & crossdrilled for oil supply to the phaser mechanism.
(L76 car cam might also have the drillings but doesnt have the phaser)
VVT phaser mechanism on the front of camshaft.
VVT Cam bolt.
VVT Front timing cover.

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/VVT/engineCutaway_lg.jpg

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/VVT/0903gmhtp_16_zl92_comp_cams_vvt_cam.jpg

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/VVT/0711gm_11_zgm_ls3_engine.jpg

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/VVT/0903gmhtp_04_zl92_comp_cams_vvt_cam.jpg

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/VVT/0903gmhtp_09_zl92_comp_cams_vvt_cam.jpg

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/VVT/0903gmhtp_10_zl92_comp_cams_vvt_cam.jpg

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/VVT/0903gmhtp_02_zl92_comp_cams_vvt_cam.jpg

[-Ray-]

Great description and photo's Paul. When did the L76 get described with VVT? AFM yes, but where is the VVT?

[Crazy Paul]

Great description and photo's Paul. When did the L76 get described with VVT? AFM yes, but where is the VVT?

Car L76 6.0 as per G8-GT has AFM......can run as a V4 etc

Truck Vortec L76 6.0 has AFM + VVT.......can run as a V4 and advance and retard the cam.

This gizmo on the front of the truck engines is the cam phaser (for VVT)
http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/VVT/0903gmhtp_04_zl92_comp_cams_vvt_cam.jpg

[johnbell2]

L76 in the Holden/G8 application does VVT with 'variable cam phasing'. The exact term is 'double continuous variable cam phasing' or DCVCP and is the same VVT implementation seen in the Ecotec engines (e.g. the LE5).

[Crazy Paul]

L76 in the Holden/G8 application does VVT with 'variable cam phasing'. The exact term is 'double continuous variable cam phasing' or DCVCP and is the same VVT implementation seen in the Ecotec engines (e.g. the LE5).

They sure made it stealthy (invisible to the untrained eye).

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/L76/2792209582_fd2e9269e3_o.jpg

[grandmacpubah]

dude paul is the freaking man lol where the heck do you get all these pictures?

[johnbell2]

They sure made it stealthy (invisible to the untrained eye).

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/L76/2792209582_fd2e9269e3_o.jpg

Yes, you are correct. I fail reading comprehension.

[johnbell2]

You know, now that I'm set straight on what DCVCP looks like... wonder how much that would buy us in a G8, all else equal?

[Crazy Paul]

You know, now that I'm set straight on what DCVCP looks like... wonder how much that would buy us in a G8, all else equal?

$/hp result would be way worse than a set of headers I'd imagine.

Besides that there would be a few large technical battles fitting the hardware into a car.
The cam phaser necessitates a thicker front timing cover, which then requires the truck style water pump, which forces all the pulleys forward.
So then you'd need the complete truck style front belt driven accessory pack including all brackets and pulleys.

The truck water pump I believe wont work with the car LS3 intake manifold....so you'd need the truck intake manifold, which is too tall and wont fit under the hood of the car.

:)

[beach]

Needless to say, especially for such a warranty repair, I'd hope EXACTLY the same thing went in there as came out...it's actually kind of odd that there'd be any other impression, yet there seems to be from the dealer with "but this won't fit"...

What came out is what should go in. Yes, a lot of GM LS engines are very "swappable" but in this case the truck to G8 versions, even the "same", are not.

Interesting, still.

[supercharger]

Hi, new guy here!!

I've done some research and this is my take.

The block used in the GT is a truck block with some modifications specific to the G8. Compared to the LS3 it is .2 litre smaller displacement because of a slightly smaller bore size. We also get a milder cam tuned for smooth operation and torque. The LS3 gets a higher lift cam tuned for HP (peak torque occurs at a higher rpm) and no AFM capability.

The Vette/LS3 heads use the same casting and valve sizes as the GT but have hollow valves to facilitate higher RPM operation. The GT valves are sodium filled for better thermal efficiency. The L76 intake manifold is the same part# as used on the LS3.

IMHO, the best way to describe our GT engine is a modified truck block with a Vette/LS3 top end. :)

[Crazy Paul]

Hi, new guy here!!

The valves aren't sodium filled.
The block is an LS2 block (same casting number even).
Mild cam with AFM lobes (8x) machined differently to the other (8x) normal lobes.

[majesticix]

Awesome info here. Tomorrow hopefully I'll be picking up the car. I'll be armed with some great data from this post to make sure I'm getting the right engine. I'm sure these guys know what they are doing but the fact that they had to order parts to get this engine to fit makes me wonder...and they mysteriously pulled this engine out of thin air. 3 days earlier I was under the impression one would have to be built for me from the plant and who knows how long it would take (and they hadn't done any work on my car at that point). In 3 days they managed to find an engine, rip my engine out, and get this thing ready to drop in. I'm quite impressed with how quickly things changed, just a little curious if maybe the mention of the NYS 30 day lemon law last Friday woke 'em up or if they're cutting corners.

Keep you posted...

[johnbell2]

$/hp result would be way worse than a set of headers I'd imagine.

Besides that there would be a few large technical battles fitting the hardware into a car.
The cam phaser necessitates a thicker front timing cover, which then requires the truck style water pump, which forces all the pulleys forward.
So then you'd need the complete truck style front belt driven accessory pack including all brackets and pulleys.

The truck water pump I believe wont work with the car LS3 intake manifold....so you'd need the truck intake manifold, which is too tall and wont fit under the hood of the car.

:)

pfffft... details, details.

:)

[R.Penguin]

dude paul is the freaking man lol where the heck do you get all these pictures?
CP is, indeed, the man!

I beleive his last name may be Holden! :p

[G8GT721]

dude paul is the freaking man lol where the heck do you get all these pictures?

http://i323.photobucket.com/albums/nn453/kroche721/chucknorris.jpg

[Crazy Paul]

dude paul is the freaking man lol where the heck do you get all these pictures?


CP is, indeed, the man!
I beleive his last name may be Holden! :p

Naaah I've just had 3 years head start learning about all this stuff.
CP Photobucket = 10,879 files.

[R.Penguin]

Naaah I've just had 3 years head start learning about all this stuff.
CP Photobucket = 10,879 files.
CP Photobucket = 10,879 files!

Holy shit! Back 'em up!

[todds87ss]

CP is, indeed, the man!

I beleive his last name may be Holden! :p

First name "Holden". Middle initial "M". Last name "Nutsak"!:woohoo:
jk

Thanks for the great info. This could even qualify for sticky status?

[Crazy Paul]

A truck engine with VVT (in this case L92) and keeping the LS3 car intake and throttle body can be done. This guy has used 1.5" spacer blocks behind the car style water pump, and more spacers behind all the brackets for belt driven accessories.

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/IMG_0657.jpg

[majesticix]

Got the car back, 26 days after the engine blew. What they did was replace the entire engine with an 09 G8 Engine, which I guess is slightly different from the 08 apparently. Must have moved some small things around. All covered under warranty, including nearly 4 weeks of rental.

All-in-all, glad to have the car back. Now I've got to schedule an appointment with New Era to re-dyno this puppy and put my "stuff" back on. :)

Thanks again for everyone's help, advice and knowledge. Sure is good to have knowledgeable and passionate people who own these cars.

[norm8332]

Got the car back, 26 days after the engine blew. What they did was replace the entire engine with an 09 G8 Engine, which I guess is slightly different from the 08 apparently. Must have moved some small things around. All covered under warranty, including nearly 4 weeks of rental.

All-in-all, glad to have the car back. Now I've got to schedule an appointment with New Era to re-dyno this puppy and put my "stuff" back on. :)

Thanks again for everyone's help, advice and knowledge. Sure is good to have knowledgeable and passionate people who own these cars.

Congrats. Did they do a good job? Can you tell?

[majesticix]

Well, they cleaned the thing from top to bottom, including the engine bay. Haven't seen it look that good, ever. Car ran great, and they even updated my ECM/TCM (and 2 recalls). They Armour all'd the freaking engine cover and all the plastic in there...that was a surprise.

I didn't realize there was another ECM/TCM update, I had them update it last year a few months after I bought the car. So that was cool to see. At this point, I'm pleased. Lets just hope I don't have any more catastrophic failures.

[G8GT721]

thats good to hear

[BLKG8]

Do they reset the OD after something like that?

[beach]

Do they reset the OD after something like that?

NO. Why would they? The miles are on the car overall, from body to suspension to interior, etc., not just the powertrain. Things like this always (well, not always) happen from time to time and are just parts being replaced...not the whole car.

[sales@spencershids.com]

Awesome info here. Tomorrow hopefully I'll be picking up the car. I'll be armed with some great data from this post to make sure I'm getting the right engine. I'm sure these guys know what they are doing but the fact that they had to order parts to get this engine to fit makes me wonder...and they mysteriously pulled this engine out of thin air. 3 days earlier I was under the impression one would have to be built for me from the plant and who knows how long it would take (and they hadn't done any work on my car at that point). In 3 days they managed to find an engine, rip my engine out, and get this thing ready to drop in. I'm quite impressed with how quickly things changed, just a little curious if maybe the mention of the NYS 30 day lemon law last Friday woke 'em up or if they're cutting corners.

Keep you posted...

Just two weeks ago we needed an all new rear end for a Traverse. They had us take one out of a new car on the lot and swap it in because they werent even willing to take one off of the assembly line. The day after the swap was finished the new one showed up and nobody even knew it was on the way. There are some things seriously wrong with the way GM tracks parts, but I would definately not think they are cutting corners. Especially if you are under warranty. There is a thing called CSI and it is what the dealerships live and die by. Don't worry about getting the wrong thing until you get the car back and something is wrong.

[majesticix]

Yup everything worked out. Communication could have been better but under the current circumstances with GM and Pontiac, I'm glad I'm back up and running.

[pir4te]

A truck engine with VVT (in this case L92) and keeping the LS3 car intake and throttle body can be done. This guy has used 1.5" spacer blocks behind the car style water pump, and more spacers behind all the brackets for belt driven accessories.

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/IMG_0657.jpg

So just to be clear.. is it possible to fit the L76 truck timing cover on an L77 with spacers moving accessories forward, using a modified e38 truck harness with wires for the VVT? Thinking of replacing water pump with a Davies Craig EWP anyways.
If so, I would need a cam (L92 or New Era VVT hi lift) in which case with adequate valve train upgrade and piston reliefs do you foresee PTV or major issues that can't be tuned out via e38 tables?

[Crazy Paul]

So just to be clear.. is it possible to fit the L76 truck timing cover on an L77 with spacers moving accessories forward, using a modified e38 truck harness with wires for the VVT? Thinking of replacing water pump with a Davies Craig EWP anyways.
If so, I would need a cam (L92 or New Era VVT hi lift) in which case with adequate valve train upgrade and piston reliefs do you foresee PTV or major issues that can't be tuned out via e38 tables?

Blocks are essentially the same externally, fitting the phaser to a VVT cam requires the use of the thicker timing cover.....which pushes everything forward 1.5"....your engine outer hardware will be the same as in the picture. GM went with piston reliefs so it's probably necessary for VVT. The swapping of one part for another and spacing outward to suit the new belt lines seems doable. Eliminating the stock water pump introduces a new belt routing headache.
I think the computer integration and tuning will be the most intricate part and not really something a home handyman should attempt.

[smitty67]

in canada some of the trucks came with the alloy block but crank snout is longer. long water pump,acc drives,all will be mis aligned due to short water pump style on g8's

[chrisG]

So i could build a l76 truck block and would be a direct swap in my g8 correct? Just use the rest of my original accessories?

[Slizzo]

So i could build a l76 truck block and would be a direct swap in my g8 correct? Just use the rest of my original accessories?

Planning on boosting that motor a lot? If not it's just adding weight to the front of the car that doesn't need to be there.