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Mutha · 06-28-2008, 12:42 PM

I would guess if they actually do away with the Big Block V-8, instead of down sizing it to about 396 cu. in., they will go with a long stroke, big bore (around 360 to 400 cu. in.), inline 4 or 5 cylinder, iron block engine with a side block mount super charger, similar to the old GMC 471's and 671's. My guess is they will be rated 340 - 380 HP and 500 to 550 Lb. of torque. Remember this is Just a GUESS!

I believe the LS engines, like driver is referring to, are too expensive to be utilized as Medium - Duty truck engines

Best to all - Glenn

cannon man · 06-28-2008, 01:46 PM

don't think an all-aluminum race engine will live for long in a motorhome. a torque rating is one thing. a good usable torque curve is another. i think you will see smaller engines and lines of motorhomes going slowly up the hills.

DriVer · 06-28-2008, 02:54 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by cannon man:
don't think an all-aluminum race engine will live for long in a motorhome.. </div></BLOCKQUOTE>cannon man, Did you see the LSX it's a cast iron block derivative.

cannon man · 06-28-2008, 04:30 PM

should be good if they don't put aluminum heads on it.

Davel · 06-28-2008, 06:58 PM

Driver,

Those emblems did bring back memories. That 427 Impala was the 2nd fastest car that I drove to work everyday. I also had a 375 hp 396 Camaro SS later. How many times do you think I have wished to have those two back today.

Mutha,

A big inline engine would make great torque at low rpm and the supercharger would boost the performance as well. The newest superchargers have systems that releave pressure at cruise and only require 1 hp to drive them.

cannon man,

The new cast iron block with cast iron heads using all the great new flow patterns would be a much more modern engine than the current 8.1. Head flow and cam timing determines where the torque curve falls and it could be designed to hit the sweet spot for any weight vehicle. Who would have thought just a few years ago that any engine could deliver 500 hp and deliver 25+ mpg in any vehicle. It's really amazing what they have done in the last few years.

Dave

Jackm · 06-28-2008, 07:27 PM

DriVer, Could you clarify the situation a little for my own understanding. What exactly has changed (or is changing) that will necessitate the need for a fundamentally different gasoline engine? Thanks.

Jack

Davel · 06-30-2008, 07:28 PM

Jackm,

Let me give you my best guess. After working for GM for 35 years and consulting in several other companies and industries those kind of questions are almost always answered by $$$. As LS style engines have become more powerful and efficient, diesels getting more efficient and quiet, and gas getting so expensive, my guess would be that demand for the 8.1 has fallen to some degree. There is some point where it is not economical to produce a product in low numbers and it is better for the bottom line to stop production.

GM has just announced a 4.5 diesel for the Tonowanda, NY engine plant. And there is speculation about a much larger (8.3) LS style engine for the Cadillac of the future. They would probably be better served using their production capacity on those engines than the current big block.

Anothr reason is the success of the LS motors. The 6 bolt mains make the block more stable. The engineers have spent much time on cylinder head flow and cam timing that will allow them to get better numbers out of the new engine, while the development of the old big block has been limited in recent years.

One other thing I have learned by my experience at GM is that all those logical reasons may not have a thing to do with why they are stopping production.....

Dave

Jackm · 06-30-2008, 08:03 PM

It appears that the demand for any new engine design has to be demonstrated long before any investments are made. However, it's hard to imagine where that demand will actually come from.

The automobile industry has no real need for a giant gasoline engine because of the weight and the poor mileage.

The demand within the motorhome manufacturing industry isn't significant enough to influence design issues.

That leaves the truck manufacturing industry.
But long ago, they chose diesel engines because of their high torque, relative fuel efficiency, and long design life.

This analysis suggests that the large-block gasoline engine will become virtually obsolete in the next decade or so. At this rate, we'll soon be sitting on park benches in Florida babbling about the good old days when giant gasoline engines purred like kittens and the indestructible slant six went on forever.

Jack

DriVer · 07-01-2008, 04:41 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Davel:
One other thing I have learned by my experience at GM is that all those logical reasons may not have a thing to do with why they are stopping production..... </div></BLOCKQUOTE>Dave, I am hearing that the Tonawanda plant is an antique and that "fixing" the plant in order to produce new engines would be very costly. What I understand to be fact may be not be accurate however if as you say the plant is re-tooled for diesel perhaps all those folks don't get to loose their jobs.

The L18 itself is a modification and enhancement of the L29. These engines are dated and just can't be made or modified to compete with the new LS series of engines and as such are being relegated to the pages of history. This I believe this assessment is accurate.

Davel · 07-01-2008, 08:18 PM

Driver,

The Tonowanda, NY plant is getting a $300,000,000 upgrade to build a new 5.3??? diesel and several other GM motors. It was the 7th most efficient engine plant in the US last year. The Morrain, OH plant is getting several million to build a new DuraMax that will meet all the smog requirements in 2010. That could be the replacement for the 8.1 for MH's. 360 hp and 660 lb/ft of torque.....that would move you right along and be very efficient as well.

Dave

parts_expert · 07-02-2008, 10:06 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DriVer:

The L19 itself is a modification and enhancement of the L29. </div></BLOCKQUOTE>

The 8.1 is the L18, not L19

The L19 is an early 90s 454. L29 is the late 90s 454

-Gramps- · 07-02-2008, 10:08 AM

So are we looking at gas powered rigs at 2200 lbs or greater going the way of the dino? Unless something happens to lower the price of diesel (and it will soon) and make it even with gas again, not to mention perception of high maintenance costs, I am not sure how only diesel engines is going to help sales of class A's as a whole.

I am glad I bought my fancy Dino now. Might not get it later. Actually with my exact coach you can't get it later!

DriVer · 07-02-2008, 12:49 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by parts_expert:
The 8.1 is the L18. </div></BLOCKQUOTE>Thank you.

Explore America · 07-02-2008, 12:50 PM

Do we know that the GM8.1L specifically for RV use will in fact be discontinued in 2010? My conversations with WCC seem to suggest that they are still in the dark about a GM8.1L replacement, and plan to continuing using this powerplant. I'm thinking since we are fast approaching this date, WCC would have to know in order to properly test a new powerplant/tranny with their chassis. Maybe somewhat similar situation to the currently non available optional International Maxxforce diesel in the UFO chassis, as their engineers are apparently still working to optimize the engine/tranny to work with the UFO chassis?