GM's new 4.2L DOHC twin turbo V-8 !!

[hoffman900]

Here's something I don't understand....

It takes a lot of money to develop a new engine platform. While modern design tools speed up the process, you still need to do reliability testing, emissions certification, etc. There is also expensive tooling required for a new platform.

If you look at GM in the last 20 years, starting with the first LS, right up to the current LT1, there have been significant changes to the V8 platform. Contrast that with the Gen 1 SBC that hung around for 40 years with only minor tweaks.

Sales volumes are way down compared to the Gen 1 SBC era (1 million Impalas produced in 1965 alone, most with v8 power). How can they justify the expense of producing these new designs? Especially something like this 4.2L v8 for niche applications with low sales volumes? From a business perspective, it's hard to see where the payback is on a project like this.

Part of it is exactly BECAUSE there are things like emissions certification. The LS architecture replaced the SBC because the SBC wouldn't cut it anymore. Likewise the LT replaced (is replacing?) the LS because the LS isn't good enough.

The rest of it is, if you don't continually improve, you die. Chevy's making the SBC for 40 years, or at least the mentality behind making the same engine for forty years, was a good chunk of what was killing GM in the 70s and later. No innovation, just resting on laurels and then wondering how come people were buying imports instead of a brand new '64 Malibu with box styling.

Leyland British did that - look where it got them. They were still building cars that were designed in the 1950s up into the 1980s.

[swampbuggy]

GM is getting by with cast alum. engine blocks, but that does NOT mean that they are equal to a high quality cast iron block. Mark H.

[Newold1]

Mark
Please describe what you mean by saying GM is "getting by" by making and using aluminum blocks.

My God, they have sure "gotten by" well making millions of great aluminum blocks.

As far as high performance and medium duty truck use, just look at the success of the LS family of engines and there lack of just "getting by"!

I am not a spokesman for GM or it's offerings, but you guys can't be real when you are making statements like these. The facts just don't support or prove up your opinions! GET REAL !!

[pdq67]

Let's look at it this way!

My bought new in Oct., '66, 1967 Camaro 350 SS/RS cost right at $35 to $3600 so was optioned out and pricy vs a base stripper car. And I still have my order form..

What would it cost in todays $Dollars?

So we can compare prices of the first year Camaro car to the latest one.

I would do a pair of 'Vette's, but I don't have any numbers...

pdq67

[Newold1]

I hear what you are saying (complaining about) about timing chain potential issues in DOHC engines. Yes they are a lot more complex timing systems than a single OHV engines but there is a required reason. They are operating 4 overhead camshafts and now recently variable cam timing systems, cylinder deactivation systems and sometimes driving accessory systems. Are there a small percentage of failures in all of these HUNDREDS OF MILLIONS timing chain drive systems out there, YOU BET! Does this relegate all DOHC timing chained engines to the horrible status you want to give them, HELL NO!

I am not sure as to whether there is a rear seal in this new LTA engine sealing the water pump from the timing chain area,which if it leaked would allow water into the crankcase, but I will find out. I know currently all of GM's late model 2008-0n DOHC V-6's do not have a potential seal leak from the rear of the water pump into the crankcase timing chain area. I these engines even though the timing cover houses the water pump rear, the gasket sealing of the rear of the water pump mounting does not allow this intrusion into the crankcase to happen even if the gasket fails.

I will also say I own a 2011 Cadillac SRX (wifes car) with a V-6 DOHC DI engine and 176,000 miles that has been repair free and no engine issues for that entire 8 years! Pretty good example of how reliable these new DOHC engines can be with proper oil changes, service and care. ALL ALUMINUM engine by the way. I also own a 2008 Cadillac Escalade with the 405HP ALL ALUMINUM L92 V-8 engine with 172,000 trouble free engine miles.

I think most people know there are NO PERFECT PEOPLE AND THERE ARE NO PERFECT CARS OR ENGINES! Get used to the FACT we live in an IMPERFECT World! Are there reasons to know and believe that these newer engine offerings are getting better year by year. The numbers and facts SOLIDLY prove that fact!

I am a knowledgeable engine optimist who believes that when it comes to today's new engine offerings from GM at least the glass is almost full!

LIFE IS GOOD! FOR MOST OF US, SO REVEL IN THAT FACT, TAKE A CHILL PILL AND ENJOY THE RIDE!

[hoffman900]

What’s incredible to me is the service intervals and what people had to do just to keep their cars going 40+ years ago. Not only that, it was expected and tolerated!

We’ve come a loooooonnng way.

[Ron E]

I think it's getting harder and harder to get large displacement engines through emissions and this engine is a reflection of that reality.....so the investment is a life or death choice not a simple would I rather choice.

If that's the case, then it makes perfect sense.

[swampbuggy]

Newold, what i meant by what i said (wrote) GM is getting by using CAST alum. blocks is this......the torque, H.P., and RPM's GM is asking these C.A. blocks to tolerate (hold up to) is not a problem, double or triple these numbers and i am saying a cast iron block would be better, thats all i meant. Not trying to argue at all.

[Newold1]

Swampbuggy:

I understand where you are coming from. I used to have issues with the use of aluminum in engine blocks but thank gosh they have really improved the strengths of aluminum blocks with the use of finite analysis, Cad/Cam design and structural engineering. Todays aluminum new core construction techniques coupled with better alloys, pressure casting, hipping processes, precision CNC machining and of course testing methods have made performance aluminum blocks actually in many cases stronger than iron blocks, especially over those designed and produced back in the 70's -90's.
Lets take for example those little Honda 4 banger blocks they now race turbocharged in 1000-1500HP versions. Let's consider the Ford Eco-Boost V-6 aluminum blocks that were turbocharged to 750HP and ran in Ford GT's and won in the 24 hours of Lemans! This same Ford V-6 stock block ran and one the 24 hours of Daytona in the GP cars. The GM 4 cylinder Ecotec all aluminum engines that now race in huge numbers in 400-1000hp stock block configurations. And then there are all the LS and LT GM aluminum engines that run the gamut from 425HP up to 750HP in absolute stock factory packages and with mods go up to 700-2000hp N/A & turbocharged in all forms of racing.

The point here now in today's world is that concerns about using aluminum blocks especially in factory stock vehicles and trucks of all kinds is really not and should not in today's automotive engine development state be a worry or concern. It's nice to know that all those aluminum soft drink cans can be reused for something as hot as an aluminum racing engine! HA!

Another few things nice about this new engine design from GM is that this engine block itself is really stout for its size and it has high strength press in register bore sleeves and not the thinner cast in iron sleeving that GM uses in the LS and LT aluminum engines. This makes for a stronger block and an easier engine to rebuild with new sleeves that press in without cutting and weakening the block cutting out the cast aluminum backed iron sleeves.

If one really studies the design, specs. and features of this new engine one will quickly see that 4 years of development and existing engine study allowed the GM engineers the opportunity to develop a pretty incredible little 550HP 4.2L engine that can easily be upgraded with some more boost and programming to an easy 700-800hp level with great durability.

This new LTA engine can be easily bored to 89mm and stroked to 95mm and produce a 4.7 liter version which in stock spec. form would produce about 650HP at the same stock 20psi boost levels! Up this boost to about 30psi and holy cow batman HP levels would be pretty incredible for a small modestly boosted V-8 that weighs less than 450lbs!

Let's hope this new GM offering provides all the positives it is capable of. Car buyers and enthusiasts deserve at least that!

[Truckedup]

Let's look at it this way!

My bought new in Oct., '66, 1967 Camaro 350 SS/RS cost right at $35 to $3600 so was optioned out and pricy vs a base stripper car. And I still have my order form..

What would it cost in todays $Dollars?

So we can compare prices of the first year Camaro car to the latest one.

I would do a pair of 'Vette's, but I don't have any numbers...

pdq67

Ratio that to your wage back then. Then ratio the same type of car at todays prices to the same type of job wage now. What did you discover?

And that 67 Camaro had all power equipment ,a/c,real sound system, anti lock brakes ,huge radial tires with massive brakes and the onboard electronics for the engine and required safety equipment...??? And in full street trim with the A/C on, run the 1/4 in 12.5 and get 21 MPG on the highway?????
No comparison possible, and none is required because they are cars of different times...

[peejay]

lawn mower engine construction materials

Ah, there it is, the false equivalency. Just like the argument I used to see about how the LS1 was sh* because it has the same oil filter size as a Kubota lan tractor. Well, let's see, it has roller rockers, roller cam, a rigid block and a stiff crank, and good fuel and ignition control so the bores and rings wil hardly show wear after 200,000 miles. So with all that in mind, where is all this metal coming from that you need a 1 quart sized oil filter to hope to catch it all? If the concern is volume, the stiffer block means you can keep the tolerances tight so you don't need much volume, and most of the engines have oil coolers so the bearings are being given cool oil instead of hot oil that was heated up even further by a crappy eggbeater of an oil pump.

I can assure you that the alloys and techniques used in manufacturing a modern aluminum engine are closer to F-15 than Tecumseh. There are hundreds/thousands of different aluminum alloys, and modern castng techniques are remarkable. One of my friends does that sort of thing for a living, and on one road trip he was telling me about how modern aluminum castings are much stronger because of how we have the computing power to model how the aluminum shrinks at different rates in the mold as it goes from liquid to 1000F solid to room temperature at different places in the casting. This causes a lot of residual stresses. BUT, if you can model it, you can alter the processes or the part design so that those stresses are gone.

You'd probably have a heart attack to find out that most of the rest of the vehicle is aluminum too. Aluminum subframes, aluminum control arms, aluminum knuckles/uprights, aluminum calipers. Even most low end cars of the past 10-15 years have significant aluminum content, and it's everything but the bearings and bolts as you go up the chain. It's certainly nothing NEW, either - domestically, GM has been using welded-up aluminum extrusions for the front subframe on W-bodies since '01 or so, and they are usually the best part of the car when the rest of the shell is rusted out junk.

[mekilljoydammit]

... we really need to ask how come those materials aren't used in medium to large scale industrial engines, maybe because some outfits still know how to make something that will last and more trouble free?

Maybe, and this is just me thinking, because a 600hp engine that weighed 3,000 lbs wouldn't be acceptable in a passenger car, but doesn't really matter for industrial equipment?

[Newold1]

lawn mower engine construction materials

Ah, there it is, the false equivalency. Just like the argument I used to see about how the LS1 was sh* because it has the same oil filter size as a Kubota lan tractor. Well, let's see, it has roller rockers, roller cam, a rigid block and a stiff crank, and good fuel and ignition control so the bores and rings wil hardly show wear after 200,000 miles. So with all that in mind, where is all this metal coming from that you need a 1 quart sized oil filter to hope to catch it all? If the concern is volume, the stiffer block means you can keep the tolerances tight so you don't need much volume, and most of the engines have oil coolers so the bearings are being given cool oil instead of hot oil that was heated up even further by a crappy eggbeater of an oil pump.

I can assure you that the alloys and techniques used in manufacturing a modern aluminum engine are closer to F-15 than Tecumseh. There are hundreds/thousands of different aluminum alloys, and modern castng techniques are remarkable. One of my friends does that sort of thing for a living, and on one road trip he was telling me about how modern aluminum castings are much stronger because of how we have the computing power to model how the aluminum shrinks at different rates in the mold as it goes from liquid to 1000F solid to room temperature at different places in the casting. This causes a lot of residual stresses. BUT, if you can model it, you can alter the processes or the part design so that those stresses are gone.

You'd probably have a heart attack to find out that most of the rest of the vehicle is aluminum too. Aluminum subframes, aluminum control arms, aluminum knuckles/uprights, aluminum calipers. Even most low end cars of the past 10-15 years have significant aluminum content, and it's everything but the bearings and bolts as you go up the chain. It's certainly nothing NEW, either - domestically, GM has been using welded-up aluminum extrusions for the front subframe on W-bodies since '01 or so, and they are usually the best part of the car when the rest of the shell is rusted out junk.

WELL SAID!

[hoffman900]

lawn mower engine construction materials

Ah, there it is, the false equivalency. Just like the argument I used to see about how the LS1 was sh* because it has the same oil filter size as a Kubota lan tractor. Well, let's see, it has roller rockers, roller cam, a rigid block and a stiff crank, and good fuel and ignition control so the bores and rings wil hardly show wear after 200,000 miles. So with all that in mind, where is all this metal coming from that you need a 1 quart sized oil filter to hope to catch it all? If the concern is volume, the stiffer block means you can keep the tolerances tight so you don't need much volume, and most of the engines have oil coolers so the bearings are being given cool oil instead of hot oil that was heated up even further by a crappy eggbeater of an oil pump.

I can assure you that the alloys and techniques used in manufacturing a modern aluminum engine are closer to F-15 than Tecumseh. There are hundreds/thousands of different aluminum alloys, and modern castng techniques are remarkable. One of my friends does that sort of thing for a living, and on one road trip he was telling me about how modern aluminum castings are much stronger because of how we have the computing power to model how the aluminum shrinks at different rates in the mold as it goes from liquid to 1000F solid to room temperature at different places in the casting. This causes a lot of residual stresses. BUT, if you can model it, you can alter the processes or the part design so that those stresses are gone.

You'd probably have a heart attack to find out that most of the rest of the vehicle is aluminum too. Aluminum subframes, aluminum control arms, aluminum knuckles/uprights, aluminum calipers. Even most low end cars of the past 10-15 years have significant aluminum content, and it's everything but the bearings and bolts as you go up the chain. It's certainly nothing NEW, either - domestically, GM has been using welded-up aluminum extrusions for the front subframe on W-bodies since '01 or so, and they are usually the best part of the car when the rest of the shell is rusted out junk.

WELL SAID!

This place needs more of this

[Brian P]

My personal problem is with the use of inferior materials and construction techniques, that are done for manufacturing cost savings, then marketing and the unknowing claim its to make the engine better. If using lawn mower engine construction materials are the best of the best for the general publics vehicles that far exceed the cost of the older stuff of years past, we really need to ask how come those materials aren't used in medium to large scale industrial engines, maybe because some outfits still know how to make something that will last and more trouble free?

Modern aluminum casting used as an engine block is in NO way inferior to cast iron. Of course it requires proper (and different from "the old days") attention to the cylinder wall surfaces, but "modern" designs and manufacturing techniques fully address this.

To my knowledge, Honda has NEVER built an engine with a cast iron block. Honda does have a reputation for building pretty good engines ...

With large industrial engines it doesn't matter if the engine weighs many tonnes. They have much lower power ratings relative to their weight and size so the better thermal conductivity of aluminum would not be an advantage. They don't last forever, either. Most large industrial engines have replaceable cylinder lines ... because they periodically have to be replaced!