Why so many V10s instead of the 6.7 diesel?

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Mike:
  It's always bothered me that that engine got such a bad reputation. At the time it came out, it was one of the most pre-consumer tested engines ever produced. It just proves, what is still true today, you really don't know how good something is going to be, until you get it in the hands of the American consumer. Richard
 
So the old Olds diesel died pretty much died with the same reputation as the old Ford 6.0 diesel (coincidentally, I owned both and never had a problem with either one....for what it's worth). 

The new Ford 6.7L diesel is an incredable motor by all accounts on the diesel forums and it will pretty much fit in the same hole as the V-10.  I was just wondering why I hadn't seen it offered as an option in the class C and some of the smaller class A (that don't currently offer a diesel).  While the diesel motor is a little more than the gas motor, it's certainly not twice as much.  The 6.7L is an increadable motor, based on my own experience and being a previous 6.0 owner.  Even with my 5th wheel and loaded, this truck will accelerate like no other truck I've owned and very quietly and smoothly I might add.

If you don't plan on putting many miles on it and plan to spend most of your time parked then the gas rig may be the bigger bang for the buck.  But for somebody that wants to just travel and knows up front that they're going to roll the miles on, even in a class C, I believe a diesel option would certainly be a seller.  But then again, most people full timing don't use a class C.  Maybe I just answered my own question.

This topic has certainly made for some interesting and enlightening read.
 
Does anyone know if Ford 6.7's have made it into the chassis of any diesel pushers yet?  That is a heck of a motor, I know the cummins, Volvo and cats have been mainstays in the dp community but the 6.7 and the 6.6 duramax are very good motors that have great power and are super quiet. I also like the 6.7 cummins. Those three motors should be more than adequate in a dp.
 
The Cummins would need to be downrated to be used in a fairly hefty Motorhome. Torque with other larger engines is a lot better.
 
I don't think Ford is offering their diesel to anyone else - they probably use all they can build themselves. I see no advantage over the superb 6.7L Cummins, anyway. Cat doesn't make on-road engines any longer and Volvos are used only in Prevost bus chassis.

Those three motors should be more than adequate in a dp.
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Some but by no means all DPs. Mid-upper end sizes of DP need larger engines with more hp and torque than those engines can deliver. The ISL (8.9L, 1250 lb-ft and 450 hp) is a very popular DP motorhome engine and larger ones use an ISX15 (1950 lb-ft and 600 hp) or  the Detroit DD13.
 
One time, when I was working at a Chrysler store, I asked a marketing person at one of the sales schools, why the don't put a high output Hemi engine in a base stripped down model of the new Challenger. Like they did with the Roadrunner back in the 70's. He looked me straight in the face and said, "Why? We are selling everyone of them we can produce in high end, high profit vehicles. There is no practical reason to do it." Was that the smart way to look at things? It apparently was working at the time, but Chrysler and GM both went bankrupt, didn't they? I had to buy a class C because, at 31 feet, it is the only thing that will fit in the place I can park it. I would love to have the 6.7 Diesel in that van cutaway, but they just aren't out there.  I had a 460 in the previous C. We have the V10 now. It's a nice engine, but, there is a lot of shifting going on when I drive it. I miss the low end torque of the big cubic inches.  It looks to me that Ford has never made any kind concerted effort to put the diesel into the cutaway van chassis. Maybe it isn't a higher profit center.
 
I am very pleased with the performance of my Ford V10 in my 32' Class C that I full-time in.  It goes up hills well, and most importantly, is very reliable.  Never overheats, doesn't burn oil--just does what it is supposed to do.  Considering how many of these engines they have built and put into commercial vehicles, I don't think you could find anything more reliable in a gas engine. 

The other advantage is that there are so many places that are experienced at working on them, plus parts are very obtainable since there are so many vehicles in service with that engine.   

It is an old engine that I was told is in the process of being replaced.  (Used to work at Ford with engineers.)  Don't know when, but based on time to develop that could be several years.  I hope the next one is just as reliable! 
 
Ya gotta understand that any vehicle configuration that sells less than 10,000 units/year is unprofitable for any major vehicle manufacturer. They build some of them for their PR value, though.
 
Robert Ryan said:
The Cummins would need to be downrated to be used in a fairly hefty Motorhome. Torque with other larger engines is a lot better.
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Downrated?  If it hasn't the torque other larger engines have, wouldn't it have to be uprated to match them?  If this is a dumb question, please forgive me, I am merely seeking clarification.
 
Downrated?  If it hasn't the torque other larger engines have, wouldn't it have to be uprated to match them?  If this is a dumb question, please forgive me, I am merely seeking clarification.
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Ratings for the same engine in a heavier Motorhome are down rated. The Duramax when it delivered 365hp and 660lbs ft of torque in a HD Pickup was downrated to this in the MDT Topkick MDT."Power / Torque: 300 bhp (220 kW) @ 3100 rpm / 520 lb?ft (705 N?m) @1800 rpm".  800lb of torque in a Pusher type Motorhome would need a substantially larger engine. I get the impression that the Power and Torque characteristics in a HD Pickup are much more "peaky" than a Motorhome.
 
Ratings for the same engine in a heavier Motorhome are down rated.
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I don't think there is any general rule about that. Ratings can go up or down for a variety of reasons relating to drive train components, suspension, vehicle weight (which may apply here) and operating environment.  For example, the same Cummins engine is typically uprated in horsepower (and sometimes torque) in a motorhome vs other applications (bus, construction equipment, etc) because Cummins perceives it to be a less stressful operating environment.
 
Cummins engine is typically uprated in horsepower (and sometimes torque) in a motorhome vs other applications (bus, construction equipment, etc) because Cummins perceives it to be a less stressful operating environment.
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That is basically what I was getting at. The HD Pickup has a less stressful environment(on parts) than the heavier Motorhome, so it is rated higher
 
What it boils down to for me - modern diesels are better.  Gas motors are cheaper.  Unfortunately, we've got short term-itis in this country and we're on the whole trained to be interested in cheaper instant gratification, not long term investment and thinking about what is really the right tool for the job.

I've been driving a diesel car now for 10 years and I never want to go back to a thirsty, gutless high maintenance gas motor.

I really want 100% electric but they're dragging their development heels there as well.  But hooray for Tesla and their recent efforts.

About the only use I have for a gas motor is tiny ones like in weedwackers and maybe sport motorcycles.

 
Robert and Gary:  Thanks for the explanation. 

Just to be sure I understand:  horsepower and torque are reduced for an application that requires more use of peak power, thus lengthening engine life. 

In an application that will see limited peak power use horsepower and torque can be upgraded without negatively affecting engine life.

Do I have it right?
 
Use of peak horsepower isn't the only factor in the rating, but that's basically it.

Another major factor is the transmission it will be coupled with. Motorhomes often have more capable tranny than a pick-up, e.g. an Allison 2400 or 3000 instead of the Allison 1000 or a Ford 5R100. The engine's power output may be reduced to keep it within the transmission torque and hp rating.

My only real point is that it is probably a mistake to try to generalize about this. It's easy to adjust hp and torque in a modern engine, simply by altering the computer controls, so the engine manufacturer adjusts it to handle the environment the engine is going to live and work in.
 
The fact is; they sell gas RV's for rubes and people who don't mind going really, really slow up hills. Plus they sell gas rigs to people who don't want much life out of their drive train.

Ask yourself this: how many gas powered semis do you see?

::)
 
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