GM Inside News Forum banner
1 - 20 of 23 Posts

· Registered
Joined
·
1,844 Posts
Discussion Starter · #1 ·
Seems GM is gearing up for a new Corvette as well as new trucks for the 2019 model year, possibly more. Historically this has come along with a new generation of small block. The c5, c6 and c7 were released with the LS1 (gen3) LS2/LS3 (gen4) and LT-1 (gen5).

I found this post, while old, interesting.

http://www.corvetteforum.com/forums...87525-speculation-the-gen-vi-small-block.html

I've heard of GM working on another form of dynamic "DOD" as well. The cam in cam I believe was first used (but not created by) Dodge in the Viper.

Any thoughts?
 

· Registered
Joined
·
8,660 Posts
According to GM, HCCI is dead.

Cylinder deactivation might be changing because there's new tech that can deactivate any cylinder individual for any cycle

3V per Cylinder could be cool. I would expect the engine block would have a common integrated exhaust manifold like the I-4's and V6's.
 

· Registered
Joined
·
3,528 Posts
The Gen IV architecture is still relatively new, so I don't see them changing anything major until 2025.
Hopefully we'll see a small diesel, but other than that, I wouldn't expect anything anytime soon. The
changes will be to the body of the trucks, aluminum will be used in certain areas to reduce weight, mixed
in with HS Steel, ala the CT6.
 

· Registered
Joined
·
966 Posts
Yea, I don't think we will see a new generation of small block (it is possible but not likely) as there really isn't any new technology out there. There are things that they could do which would bring improvements to the line, however I just don't see them doing it for the reason of a lack of need.

The two things I would like to see is a bigger bore spacing (4.6 vs 4.4) and concentric camshaft VVT, those two things would be great IMHO.
 

· Registered
Joined
·
19,661 Posts
The Gen IV architecture is still relatively new, so I don't see them changing anything major until 2025.
Hopefully we'll see a small diesel, but other than that, I wouldn't expect anything anytime soon. The
changes will be to the body of the trucks, aluminum will be used in certain areas to reduce weight, mixed
in with HS Steel, ala the CT6.
I dunno about 2025, but it IS only just 3-ish years old. Only about halfway through to a new program.
 

· Registered
Joined
·
3,387 Posts
Do you guys ever foresee GM moving away from pushrods?

Just curious more than anything...
Up until now rumors are there are 2 v8 in near future
1. 4.2 l v8 TT DOHC
2. 6+ l v8 DOHC
There was some rumors some years ago about 3.xx l v8 DOHC also.
But nothing has been confirmed yet.
Also i don't think if GM will build any of this engine that it will be only for luxury or super sport car...but who knows..maybe they surprise us.

I'm not sure GM will move from pushrods (especially v8)..at least not in the near future.
 

· Registered
Joined
·
1,844 Posts
Discussion Starter · #8 ·
The Gen IV architecture is still relatively new, so I don't see them changing anything major until 2025.
Hopefully we'll see a small diesel, but other than that, I wouldn't expect anything anytime soon. The
changes will be to the body of the trucks, aluminum will be used in certain areas to reduce weight, mixed
in with HS Steel, ala the CT6.
Probably a typo, but Gen IV was short lived, gen V started around 2014-2016 depending on the vehicle. The Chevy SS with the LS3 is still Gen IV though.

There is plenty of new tech not incorporated in the new engines, but I'm not sure if it would be a new generation of engine or just a newer Gen V.

I think we are going to see some changes for the new Corvette and trucks.
 

· Registered
Joined
·
3,528 Posts
Probably a typo, but Gen IV was short lived, gen V started around 2014-2016 depending on the vehicle. The Chevy SS with the LS3 is still Gen IV though.

There is plenty of new tech not incorporated in the new engines, but I'm not sure if it would be a new generation of engine or just a newer Gen V.

I think we are going to see some changes for the new Corvette and trucks.
Yup...I meant Gen V, thanks for catching that! The 61 Bel Air in my profile photo is getting a 5.3L Gen IV swap. Can't wait to get it on the road again. :)
 

· Registered
Joined
·
966 Posts
The only other "confirmed" engine that is coming from GM is the 4.2 twin turbo engine as has been confirmed by JDN himself.

Rumors exist about an LT5 engine, though not confirmed or denied by GM.... any other future V-8 engine is unknown at this point.
 

· Premium Member
Joined
·
8,929 Posts
Do you guys ever foresee GM moving away from pushrods?

Just curious more than anything...
With the previously mentioned LT5 & 4.2TT, GM might be preparing for a life after pushrods. If GM ever does do away with pushrod V8s (& 4.3), GM would most likely cough up a 5.3L & 6.2L OHC engines to save on tooling.

As for those speculations from the link above, I really don't see magnesium being used for the block or the 3-valve arrangement showing up. Since the Duramax uses pushrods & 4-valve per cylinder, they would skip the 3 & go directly to 4.
 

· Registered
Joined
·
966 Posts
To be honest, the DOHC LT5 was most likely a typo (the same typo existed on the LT1 being stated as OHC as well)......

If Cadillac is getting a V-8 engine of its own and one version is 4.2L I doubt the block is big enough to support 6.2L. The old North Star had a 4.00 inch bore center spacing and the Ford modular motor/coyote has a 3.397 bore center spacing. The Ford 5.8L uses a really long stroke (4.165 inches) to get to 5.8L, they would have to do some things to make a modular block that could support strokes even longer then 4.165 inches. Though counter to that is you are hurting the engines ability to rev. I doubt if they are making a Cadillac V-8 with an early target displacement of 4.2L that they will make the block big enough to realistically support engine sizes as high as 6.2L. The 5.0L Coyote is taller and wider then the 6.2L LS3 and that is with a smaller block, give the Cadillac a block as big as the Chevy small block and it won't fit in the Corvette and probably wouldn't fit in the Camaro engine bay.

I believe we will see a Cadillac exclusive V-8 engine that is based on a smaller block (like the North Star) which makes more sense from a packaging stand point which would have a maximum engine size of around what the North Star had. Making it small and with a turbo will allow it to fit in engine bays that were designed around 2.0T and V-6 engines. If they made a small block chevy sized block with DOHC the trucks might be the only thing it could fit in at GM. Remember the small block chevy will support engine sizes as high as 7.4L (454).
 

· Registered
Joined
·
1,844 Posts
Discussion Starter · #14 ·
To be honest, the DOHC LT5 was most likely a typo (the same typo existed on the LT1 being stated as OHC as well)......

If Cadillac is getting a V-8 engine of its own and one version is 4.2L I doubt the block is big enough to support 6.2L. The old North Star had a 4.00 inch bore center spacing and the Ford modular motor/coyote has a 3.397 bore center spacing. The Ford 5.8L uses a really long stroke (4.165 inches) to get to 5.8L, they would have to do some things to make a modular block that could support strokes even longer then 4.165 inches. Though counter to that is you are hurting the engines ability to rev. I doubt if they are making a Cadillac V-8 with an early target displacement of 4.2L that they will make the block big enough to realistically support engine sizes as high as 6.2L. The 5.0L Coyote is taller and wider then the 6.2L LS3 and that is with a smaller block, give the Cadillac a block as big as the Chevy small block and it won't fit in the Corvette and probably wouldn't fit in the Camaro engine bay.

I believe we will see a Cadillac exclusive V-8 engine that is based on a smaller block (like the North Star) which makes more sense from a packaging stand point which would have a maximum engine size of around what the North Star had. Making it small and with a turbo will allow it to fit in engine bays that were designed around 2.0T and V-6 engines. If they made a small block chevy sized block with DOHC the trucks might be the only thing it could fit in at GM. Remember the small block chevy will support engine sizes as high as 7.4L (454).
I really don't think the DOHC reference was a typo, we've heard from other places therr may be a DOHC engine in the works. I believe it was Kaltech, but I can't remember the exact source.

Dohc may be mid engine Corvette only though.

The new trucks and c8 Corvette will bring about either a gen6 engine or improvements to the gen5.
 

· Registered
Joined
·
3,387 Posts
I really don't think the DOHC reference was a typo, we've heard from other places therr may be a DOHC engine in the works. I believe it was Kaltech, but I can't remember the exact source.

Dohc may be mid engine Corvette only though.

The new trucks and c8 Corvette will bring about either a gen6 engine or improvements to the gen5.
It was Katech


But they didn't said which type of valvetrain will it use (cam in block or DOHC)
 

· Registered
Joined
·
966 Posts
I really don't think the DOHC reference was a typo, we've heard from other places therr may be a DOHC engine in the works. I believe it was Kaltech, but I can't remember the exact source.

Dohc may be mid engine Corvette only though.

The new trucks and c8 Corvette will bring about either a gen6 engine or improvements to the gen5.
Yes there is a DOHC engine in the works.... it is the 4.2TT V-8 that is going into the Cadillac CT6 sedan.
 

· Registered
Joined
·
966 Posts
TT, it better pack over 550 HP
If you remember they stated it will produce power in the upper 400BHP range, if we are going to go off of what is mostly confirmed about this engine. They also stated that this will not be a "performance" engine so I can see this engine focus being on NVH over all else.

I honestly do not see a sixth generation small block so soon, the current 5th generation small block really incorporates all of the features that we will likely see from the XV8 engine. Although I can see concentric camshaft VVT being added to the lineup.
 

· Registered
Joined
·
3,746 Posts
Do you guys ever foresee GM moving away from pushrods?

Just curious more than anything...
Personally, unless a new valve/ air inflow-exhaust system comes along that retains the or improves the advantages of pushrods, no. They will probably offer DOHC V8 for Cadillac only for perception reasons.
 

· Registered
Joined
·
1 Posts
What is old is new again. GM just announced the gen 6 small block V8 for 2025, at least for trucks and SUV's. It will be for everything of course, they're doing a gen 6 to meet draconian 2025 pollution and mileage standards. That probably will require 4 valves although GM hasn't announced specs. The midenginecorvette forum opened a page about the new V8 and closed it the next day. GM doesn't want to lose Corvette sales with people waiting to get a DOHC LT1, if the gen 6 retained the OHV they would have said so.
 
1 - 20 of 23 Posts
Top