New GM diesel 1

[dgallup]

Despite all the nay sayers putting down the reversed diesel head layout (exhaust in valley of V) in thread71-184766, GM has announced the 2010 Duramax V8 diesel will use this layout. It definitely offers some packaging advantages as well as challenges. Hopefully GM will sweat the details on this one & not unleash another "Oldsmobile diesel" on an unsuspecting public.

http://www.sae.org/automag/technewsletter/080108Tech/01.htm

 

[j2bprometheus]

In my opinion, the primary reasons for choosing this layout were packaging constraints. GM probably wanted the diesel to fit in the same space as the gasoline engine.

 

[IceStationZebra]

Yep, thats what the article (you obviously didn't read) said.

This news makes me feel like a prognosticator with my previously mentioned post. Its surprising that the engine is only a 4.5L but they had to go with the narrow 72° bank angle and no manifolds to keep the engine narrow enough? Makes me suspect this will end up in the smaller SUVs and trucks.

I would hope that the intake flows well with the near vertical intake port. I also wonder if having the intake cover the cam helps with NVH? I think the rib on the cover is big enough! I wouldn't be surprised if they add some type of high temp cover over the exhaust cam to satisfy marketing and improve NVH some more. I also noticed that the covers on this picture are different? (

http://blogs.edmunds.com/Straightline/2935)

Also reportedly "With a 4.5-liter diesel, a six-speed automatic and a couple of other tweaks, [a two-wheel drive Chevrolet Silverado] can achieve close to 30 mpg highway." All at a $5700 premium.

ISZ

 

[tbuelna]

"the primary reasons for choosing this layout were packaging constraints"

Sort of. It's all about emissions controls. The DOC needs to be as close to the exhaust valve as possible. Putting the turbo in the engine V keeps the exhaust plumbing short going into the DOC, and thus keeps the exhaust gas temps high.

 

[Thecardoc]

Engines like this put a premium on just how important the auto technician really is. The field is demanding an ever more talented and trained individual all of the time, yet is way behind the compensation levels that the person with the right abilites can get in almost any other field.

Oh, and everytime I hear someone say the imports are more advanced than the domestics, I just think about all of the innovations we have had just like this engine.

 

[dgallup]

IceStationZebra - I remembered you original post but it was closed so I had to start a new one. This engine is DOHC so they had to go to the lower displacement and narrower valve angle to stay inside the SMB envelope. However, it looks to me like it is going to be a bit taller than a SMC. I think there will be a big market for this motor in light duty pickups & SUVs.

I would love to see how they are keeping the intake air & valve train/cam lubrication separated. I can't quite picture it myself.
"The heads' unique two-tiered internal construction segregates the intake route, the chain-driven DOHC valvegear, and water jacket. (The fully dressed engine on display was not sectioned, so no internal details were revealed.)"

 

[RossABQ]

Very nice engine, no doubt, but doesn't it seem as though the same concept in maybe 3L size is more appropriate for the future SUV/light pickup market? It seems to me this is sized to maintain 4500+ lb light trucks' performance at high levels.

I'm sick of being surrounded in commuter traffic by PowerStroke'd F-350 4x4 4-doors that don't have a scratch on their load beds, or even a trailer hitch... Not a technical issue, of course

 

[IceStationZebra]

I thought about the DOHC setup being wider AFTER I posted my reply. I could also argue that it must have a bore large enough to accommodate 4 valves & injector - so being an 8 cylinder of only 4.5L the stroke probably isn't overly long and therefore a reasonable deck height. But I do have to agree that it looks tall.

As for the intake I think there is a plenum above the intake cam and the ports wrap around the outside of the "cam cover." If you look closely you can make out 4 bulges behind were the intake connects to the cover.

I have to agree with RossABQ. I was surprised that this engine is both an 8 cylinder and over 4 liters. I was hoping for a medium-light diesel that could use a lightly modified transmission & axles from the petrol engines to keep the "premium" costs down and the efficiency up. I imagine that one of the main drivers for customer acceptance was 0-60 time for highway merging. There is also the paradigm in this great USA that diesels are meant for hauling not economy.

ISZ

 

[Majik]

I have no doubt that changing injectors in this will be only 5x as worse as in a normal duramax and parts will be just as high.

Looks like it's got sucker written on it. Customers will only pay so much for labor before they will be fed up with poorly packaged engines.

 

[GregLocock]

Mike, the only guys the big 2.4 sell to are the original buyers. They won't be replacing injectors before they sell it. Chances are whoever buys the car secondhand will be the arbiters of the real cost of the design.



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Thecardoc]

quote[I have no doubt that changing injectors in this will be only 5x as worse as in a normal duramax and parts will be just as high.

Looks like it's got sucker written on it. Customers will only pay so much for labor before they will be fed up with poorly packaged engines.] quote

As an auto technician who very likely will find myself servicing this engine in the future this comment portraits the biggest problem we face just about every day we get to work. We study, and equip ourselves with the tools and information necessary to diagnose and repair "transportation equipment", only to see a huge portion of consumers act like we are working on a $200 appliance. The perspective of the quote above turns into a self fullfilling prophecy that needs to be broken. Consumers that understand that these machines need serviced, and that it simply costs what it has to cost are the ones that not only see the value in having the equipment but trained professionals available to service it when necessary. The ones that purchase this technology, and then moan and complain that it's ownership also comes with a certain level of responsibility for it's up-keep actually work to thin the number of shops and technicians available to do so when that day finally comes. Strange as it may seem, this drives the cost up, while arguably forcing the quality (of the technician) down! Both of those points would be ones "the consumer" would if asked say they don't want, yet their purchase habits dictate otherwise. The heart of the problem really comes from manufacturers that try to tell the public their product is "virtually naintanence free" when no such "machine" is ever going to be built.

I can't tell you how many times I have overheard a conversation where someone was failing to have a vehicle repaired, while I knew there were competent techs and shops that could easily solve the problem. The reason they were not getting the car fixed was they weren't looking for an educated, and equipped technician, they were looking price first and therefore rewarding the people without the tools and schools for not investing in them with their business.

 

[SomptingGuy]

Thecardoc:

I agree. Cars have ownership costs and risks. Many people see spending money on maintaining their car a waste. Yet they will happily spend £50 a week putting petrol into it. My car (well, my ex wife's car I guess) is over 20 years old, has 170k+ on the clock and is still regularly serviced.

My only complaint is insurance - government-mandated gambling.

- Steve

 

[RossABQ]

With today's increased complexity, you could easily spend a couple grand on "routine" repairs on a car that is technologically yesterday's news, and really serious bucks on some of the "major" repairs that are inevitable. Consider that people are loath to pony up maybe $1000 nowadays for a well-rebuilt GM TH350 automatic trans, as cheap as they come, for a 15-yr-old vehicle that is otherwise in good condition. How much will a rebuild on a 10-yr-old 6-speed ZF set you back in 2017? Will people put a $10k trans into a $20k car at that point? (The hottest products in 2017 may well be adapters to hook up TH350's to M-B's and BMW's!)

 

[btrueblood]

Cardoc,

I don't see where the OP slammed car tech's. The slam is against the design of an engine that makes necessary maintenance un-neccesarily more complex and difficult. Like burying an oil filter at the back of an engine between the exhaust manifold and the engine case (Saturn), or my old Opel that required dropping the engine out the bottom of the car to work on the heads (and "customizing" a socket wrench to change the #4 spark plug). I'm more than willing to find shops with competent mechanics and to pay them extra for their service, as I like having my cars running well for 10+ years (and don't much like driving away from a quickie-lube place, watching the oil pressure steadily drop, blue smoke coming out the back...they left the oil filler cap off...they will only do that once for me).

 

[dicer]

Thecardoc:

I agree. Cars have ownership costs and risks. Many people see spending money on maintaining their car a waste. Yet they will happily spend £50 a week putting petrol into it. My car (well, my ex wife's car I guess) is over 20 years old, has 170k+ on the clock and is still regularly serviced.

My only complaint is insurance - government-mandated gambling.
- Steve
=============================
Yeah, and it doesn't seem to bother them to pay a $300 a month or more for a car payment for a new one either. If they put that in the old one for a year, they wouldn't need the new one.

 

[TDIMeister]

A current discussion in another forum involving balance shafts in another automotive Diesel engine, plus the offset crankpins that an unusual 72-degree V-angle requires, and the weakening they cause the crankshaft, can be no good things.

 

[bradvr4]

http://en.wikipedia.org/wiki/BMW_N63

features a reverse-flow air design in which the turbochargers are mounted in the engine valley and the intake manifolds are located on the sides of the block. This new design creates a more compact engine package and reduces the width of the assembled engine. The engine uses air-to-water intercoolers, which is more efficient and orvides a shorter air path than using a standard air-to-air intercooler.



Interesting considering how much hotter a petrol engine runs compared to a diesel, and they've kept with two turbos as well, so it isn't as if their only goal was to keep the exhaust manifold lengths down on a V engine with one turbo