GM may debut 6.2L V8 with overhead cam design in 2011
10-01-07, 12:15 PM
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GM may debut 6.2L V8 with overhead cam design in 2011
Second United Auto Workers Agreement Reveals General Motors' Potential Future Truck Plans
By: Mike Levine Posted: 10-01-07 12:30 PT
This is the toughest story I've written.
On Friday afternoon I watched the newswires and Wall Street Journal break information about GM's future product plans that were revealed in the "White Book" agreement between GM and the UAW settling last week's strike.
One of the items that caught my attention was the name of GM's next full size truck platform, C3XX. So, I went and did some more background searching on the 'C3XX' identifier, using Google.
To my surprise a second, internal UAW-GM document appeared in Google's search results. The document can be found on the Future of the Union website and Google's publicly available search cache.
On Friday the document ranked much higher in the seach results, before the "White Book" news containing the 'C3XX' term at more popular websites moved up in Google's page rankings.
The information about what's contained in that document is in the story below.
After wrestling with this decision, and consulting with several colleagues, I've decided to publish this story because I believe it's relevant to the "White Book" news and GM's current state of affairs with the UAW.
- M.L.
A document found online (using Google) at the Future of the Union website suggests that General Motors is preparing to substantially overhaul the engine lineup used in its next generation full size trucks.
Future of the Union has published an internal memorandum of understanding that contains detailed information about contract negotiations that took place in June 2007 among the United Auto Worker (UAW) union, General Motors (GM), and GM’s largest supplier, Delphi.
The document contains GM’s future product commitments to UAW-represented employees at Delphi, similar to the future product timelines that emerged from the recent strike settlement contract between GM and the UAW.
Most notable are the powertrain components that Delphi is expected to supply for use in the C3XX truck program, starting in 2011. The C3XX platform will replace the current GMT 900 architecture that underpins the Chevrolet Silverado and GMC Sierra full size pickups.
According to the document, C3XX pickups will feature a new 'Gen V' 6.2-liter dual overhead cam (DOHC) V8 engine - a major departure from GM's traditional overhead valve (OHV) pushrod engine design used in its trucks, like the ‘Gen IV’ 403-horsepower / 417 lb-feet L92 6.2-liter V8 under the hood of the GMC Sierra Denali. The only DOHC V8 GM currently offers is Cadillac’s 320-hp / 310 lb-ft 4.6-liter Northstar engine.
The Gen V 6.2 motor will use variable valve timing (VVT) like the Gen IV 6.2, but the use of dual overhead cams holds the promise of four valves per cylinder instead of the current two valves, for better intake and exhaust flow and increased power. This is a similar setup to the 5.7-liter i-Force V8 used in the Toyota Tundra, but the Gen V 6.2 will also offer GM's active fuel management (AFM) system. AFM shuts down half the cylinders during steady state running for improved fuel economy – a feature not currently available for the i-Force. Up until this point, it’s been conventional wisdom that implementing cylinder deactivation on OHC engines is impractical for reasons of cost and complexity.
Pushrod engines won’t be disappearing entirely from GM’s truck line. A new ‘Gen V’ OHV V8 will replace the current 320-hp / 340 lb-feet 5.3-liter V8. Apparently the final displacement hasn’t been determined yet, because it’s referred to as 5X.
The new 5X gasoline engine will feature spark ignition direct injection (SIDI), like a diesel. SIDI places the fuel injector right inside the combustion chamber, so fuel can be directly mixed with air entering the chamber during the intake stroke instead of before it enters the chamber, like in a conventional multi-port fuel injected gas engine. This approach enables a leaner burn of the fuel at higher compression ratios than current gas engines, resulting in greater fuel economy, cleaner emissions, and more power.
Initial production of both engines is slated to start in 2011 with full production in 2012.
Of course, it's possible that because this information is still approximately three years out in time, plans detailed in this document for the full size truck powertrains could still change.
Contacted for comment, a GM spokesperson told PickupTruck.com that GM doesn't make statements about documents like this.
There was no phone number or names listed to contact the Future of the Union website for comment.
By: Mike Levine Posted: 10-01-07 12:30 PT
This is the toughest story I've written.
On Friday afternoon I watched the newswires and Wall Street Journal break information about GM's future product plans that were revealed in the "White Book" agreement between GM and the UAW settling last week's strike.
One of the items that caught my attention was the name of GM's next full size truck platform, C3XX. So, I went and did some more background searching on the 'C3XX' identifier, using Google.
To my surprise a second, internal UAW-GM document appeared in Google's search results. The document can be found on the Future of the Union website and Google's publicly available search cache.
On Friday the document ranked much higher in the seach results, before the "White Book" news containing the 'C3XX' term at more popular websites moved up in Google's page rankings.
The information about what's contained in that document is in the story below.
After wrestling with this decision, and consulting with several colleagues, I've decided to publish this story because I believe it's relevant to the "White Book" news and GM's current state of affairs with the UAW.
- M.L.
A document found online (using Google) at the Future of the Union website suggests that General Motors is preparing to substantially overhaul the engine lineup used in its next generation full size trucks.
Future of the Union has published an internal memorandum of understanding that contains detailed information about contract negotiations that took place in June 2007 among the United Auto Worker (UAW) union, General Motors (GM), and GM’s largest supplier, Delphi.
The document contains GM’s future product commitments to UAW-represented employees at Delphi, similar to the future product timelines that emerged from the recent strike settlement contract between GM and the UAW.
Most notable are the powertrain components that Delphi is expected to supply for use in the C3XX truck program, starting in 2011. The C3XX platform will replace the current GMT 900 architecture that underpins the Chevrolet Silverado and GMC Sierra full size pickups.
According to the document, C3XX pickups will feature a new 'Gen V' 6.2-liter dual overhead cam (DOHC) V8 engine - a major departure from GM's traditional overhead valve (OHV) pushrod engine design used in its trucks, like the ‘Gen IV’ 403-horsepower / 417 lb-feet L92 6.2-liter V8 under the hood of the GMC Sierra Denali. The only DOHC V8 GM currently offers is Cadillac’s 320-hp / 310 lb-ft 4.6-liter Northstar engine.
The Gen V 6.2 motor will use variable valve timing (VVT) like the Gen IV 6.2, but the use of dual overhead cams holds the promise of four valves per cylinder instead of the current two valves, for better intake and exhaust flow and increased power. This is a similar setup to the 5.7-liter i-Force V8 used in the Toyota Tundra, but the Gen V 6.2 will also offer GM's active fuel management (AFM) system. AFM shuts down half the cylinders during steady state running for improved fuel economy – a feature not currently available for the i-Force. Up until this point, it’s been conventional wisdom that implementing cylinder deactivation on OHC engines is impractical for reasons of cost and complexity.
Pushrod engines won’t be disappearing entirely from GM’s truck line. A new ‘Gen V’ OHV V8 will replace the current 320-hp / 340 lb-feet 5.3-liter V8. Apparently the final displacement hasn’t been determined yet, because it’s referred to as 5X.
The new 5X gasoline engine will feature spark ignition direct injection (SIDI), like a diesel. SIDI places the fuel injector right inside the combustion chamber, so fuel can be directly mixed with air entering the chamber during the intake stroke instead of before it enters the chamber, like in a conventional multi-port fuel injected gas engine. This approach enables a leaner burn of the fuel at higher compression ratios than current gas engines, resulting in greater fuel economy, cleaner emissions, and more power.
Initial production of both engines is slated to start in 2011 with full production in 2012.
Of course, it's possible that because this information is still approximately three years out in time, plans detailed in this document for the full size truck powertrains could still change.
Contacted for comment, a GM spokesperson told PickupTruck.com that GM doesn't make statements about documents like this.
There was no phone number or names listed to contact the Future of the Union website for comment.
10-01-07, 10:00 PM
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sweet, bout time, hopefully it will make it into a sports car from them. Imagine that, GM making sports cars with independent rear suspensions and DOHC motors, whoda thunk it!
10-02-07, 11:39 AM
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2011?
Seriously....A new Tundra would be due in like what? 2012?
By that time the Tundra's 5.7 V8 should have Direct injection AND Valvematic.
The future is now GM, thanks for finally getting with the program, but isn't that a lil too late?
Seriously....A new Tundra would be due in like what? 2012?
By that time the Tundra's 5.7 V8 should have Direct injection AND Valvematic.
The future is now GM, thanks for finally getting with the program, but isn't that a lil too late?
10-02-07, 11:54 AM
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Gosh those pushrods are good for nothing except making mass amounts of power with low cost, high reliability, great fuel economy, light weight packaging and compact dimensions.
GM may have had some problems with build quality and perceived quality the last 2-3 decades, but powertrains are an area where GM has almost always been very competitive with. Especially V8s.
10-02-07, 01:55 PM
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Right, because god only knows that GM is currently sorely lacking in the powertrain department.
Gosh those pushrods are good for nothing except making mass amounts of power with low cost, high reliability, great fuel economy, light weight packaging and compact dimensions.
GM may have had some problems with build quality and perceived quality the last 2-3 decades, but powertrains are an area where GM has almost always been very competitive with. Especially V8s.
Gosh those pushrods are good for nothing except making mass amounts of power with low cost, high reliability, great fuel economy, light weight packaging and compact dimensions.
GM may have had some problems with build quality and perceived quality the last 2-3 decades, but powertrains are an area where GM has almost always been very competitive with. Especially V8s.
hint*its more efficient
10-02-07, 02:40 PM
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Why do you classify OHC designs as "reliable technology" vs OHV? Why is it ">" OHV? What exactly is more efficient?
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10-02-07, 03:51 PM
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Threxx, from an engineering-design standpoint, an OHC engine is more efficient than a pushrod motor (commonly called OHV since it was distinctly different from the old flathead motors). Efficiency is a term thrown around a lot today, but IIRC its best defined in M.E. terms by power output vs power input. Determining the Power input of the air and fuel going into a motor is up for debate 
Their lightened valvetrain can continue to flow air at substantially higher rpms with better reliability and from what I've been told, there is an inefficiency with a cam pressing a lifter that presses a pushrod that pushes a rocker that pushes down onto a valvespring vs a cam pressing down onto a shim that rests directly on the valvespring. There are a myriad of other reasons BUT, the bottom-line is:
DOHC motors make more power with less displacement, generally have lower emissions (please show me the LS-based V8 that has a ULEV2 rating, not sure on the LS3 though) and generally have better gas mileage. Other valvetiming and lift technologies such as Vtec, VVTLi, VANOS also enhance these figures. New technology such as Valvematic will push the advantage even further into the OHC camp.
GM's pushrod V8s make good power, get decent gas mileage IF you can run 1100-1200rpms at 70mph in top gear (what car wouldnt? I remember the A4 trannies getting mid teens gas mileagewise), and package very well. Somehow I dont think they cost all that much less than a comparable Toyota V8; and they obviously can't make similar power.
This is a good move for GM; but they should have planned it about 4 years ago so they could have it available now. Hopefully they dump A LOT of cash into the project and build something extraordinary. It'd be smart of them to hire outside consultants for OHC motor-design since they obviously dont have a clue with them.
Their lightened valvetrain can continue to flow air at substantially higher rpms with better reliability and from what I've been told, there is an inefficiency with a cam pressing a lifter that presses a pushrod that pushes a rocker that pushes down onto a valvespring vs a cam pressing down onto a shim that rests directly on the valvespring. There are a myriad of other reasons BUT, the bottom-line is:
DOHC motors make more power with less displacement, generally have lower emissions (please show me the LS-based V8 that has a ULEV2 rating, not sure on the LS3 though) and generally have better gas mileage. Other valvetiming and lift technologies such as Vtec, VVTLi, VANOS also enhance these figures. New technology such as Valvematic will push the advantage even further into the OHC camp.
GM's pushrod V8s make good power, get decent gas mileage IF you can run 1100-1200rpms at 70mph in top gear (what car wouldnt? I remember the A4 trannies getting mid teens gas mileagewise), and package very well. Somehow I dont think they cost all that much less than a comparable Toyota V8; and they obviously can't make similar power.
This is a good move for GM; but they should have planned it about 4 years ago so they could have it available now. Hopefully they dump A LOT of cash into the project and build something extraordinary. It'd be smart of them to hire outside consultants for OHC motor-design since they obviously dont have a clue with them.
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