So WHY have Ford, GM chose to use a V-8 configuration -Vs- Inline 6 with their truck Diesel engines ??

What's the Advantage of a V-8 Diesel engine ??

(Please don't reply with Ford/GM sucks BS stuff...)

 

The V8 design is a very good configuration. It is well balanced, has a simple crankshaft, revs very well, and offers a lot of displacement in a small package that is well suited to car engine bays. And people in the US are used to the idea of V8s being powerful. The common misconception is that V8s are fast and sixes are not exciting. V8s do work very well in automotive applications. Of course it has some disadvantages too, especially for heavy truck use. It has a lot more parts than a six, offers less low end torque, and may get worse mileage at a given displacement because it has more internal friction or other reasons. It also has no practical place for the turbo in the confined area under the hood of a pickup and it has two exhaust manifolds and pipes. So in a pickup with a turbo diesel, an in-line makes more sense. For a simple, fast car that runs on gasoline, the V8 makes sense. They are light and can rev to the moon. For very heavy work, like big rigs, or criusing boats, or tractors, the six begins to look better. Sixes will not rev as high as V8s because they have heavier pistons and rods for a given displacement, and diesels will not rev like gas engines because of the injection system. In our case, where we want a lot of torque, a long life, and good economy, and where we have a limited space under the hood, the inline six is hard to beat. And the Cummins is the best of that design. The most you can cram in there and still work on it easily, and the potential for more power than the rest of the truck can handle.
V8 diesels are not inherently bad at all. The problem comes with rushing something to market as fast as possible and as cheaply as possible. While trying to make it out perform everything else and having few mechanics able to work on them. And, of course, trying to cram the engine, a turbo and an intercooler in the same area as a gas V8.

Wetspirit

 

So why did Ford/GM chose the V8 over a Inline 6 configuration ??

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Because they can't match all the CUMMINS inline 6 attributes, gobs of torque, economical to run, reliable, built in durability and longevity, and easy to maintain. So they went the next best route a V-8. V-8 diesels typically have 40% more parts in them as a I-6. Guess what I own?

 

Maybe you could ask them. I've already offered my thoughts


Wetspirit

 

Something not mentioned yet, a v-8 will weigh less (as a general rule) for a given displacement than an inline style motor. This is a consideration in automobiles. I think we tote around 3-400 lbs directly over the front axle more than what the "other" guys do. Not all that big a deal just to look at it, but when you're talking 200k miles worth of extra wear on suspension and other parts, and it becomes a fairly significant engineering exercise.

 

I figure its probably partly just a marketing ploy assuming most buyers will just assume a V8 is better than a straight 6 .

 

That is the truest statement. People think because it has 2 extra pistons it is better. Most people are stupid and buy things without doing research. Thats why the ford guys are so mad at ford. And they are having their trucks bought back. If you notice since 89' dodge has been using a 5.9l cummins. The changes are only to 24valves and an electrical system. (others I'm sure but those in general). Ford and chevy have had many different engines. gm has used the 6.5l the 6.2l and the 6.6l. (might be forgetting some). Ford has used the 6.9l the 7.3 and now the 6.0(which we all know is crap). The reason they keep changing is because of lack of reliability. If and engine works well, why change it? The only reason the cummins in 07's is different is because of the EPA. Ford and chevy are gonna have to meet the requirements also.

 

I don't have have much to add on the 6 cyl vs. 8 cyl engine issue. I will say this, I went atv riding in WV this past weekend with a guy with an 05 PSD. We started them both up side by side on Sunday and his engine is noticibly louder than the CTD is, cold and warm.

He has not had any issues with it yet. He was cutting on my truck a little (joking around). I didn't say much other than go talk to the other guy that was riding with us that is a mechanic at a Ford dealership. He didn't have nice things to say about the PSD 6.0. He even said the 05 and 06's are only marginally better than the 03 and 04's were. For whatever that is worth. Another guy that was riding with us works as a mechanic at an auto auction. He said that there is a ton of 03 and 04 PSD lemon law buybacks coming through the auction.

I will say this. I didn't seize the opportunity to rip on his truck over it. I truly hope that he doesn't have problems with it (05 F350 Lariat). He paid a lot of money for it and I hate to see someone have trouble with something that they spent $50,000 plus on.

 

All the highway truck factories and equipment manufacturers know that inline diesels are the most practical in a working unit. BMW and Mercedes-Benz know that even inline gasoline engines are strongest. Mercedes has five cylinder inline automotive diesels and VW has 4 cylinder auto diesels. Inline gasoline engines can be made light and high reving for racing and they still have the advantage of a crankshaft main bearing between every crankshaft throw. Another added advantage is that the inline six gasoline engine is naturally balanced for high rpms.

Streamlining auto styling has probably been the single most important factor prompting European auto makers to switch to shorter, from front to back, V configuration gasoline engines. V engines are physically shorter for any giving displacement compared to a inline engine. Apparently GM/Ford know that the North American population has had decades of branwashing to believe a lie that V configuration is best. Dodge just wanted to build a heavy duty pickup hauler that would do the job and stand up to abuse. Dodge had nothing to loose as their past reputation for producing quality bodies was questionable. Dodge decided to be honest and promot realistic superior engineering principles, while GM/Ford tried to carry on the deception and capitalize on the population's ignorace and brainwashing. Just watch the 6.7L Cummins blow the doors off the New Duramax, because the 5.9L Cummins still gives the new duramax a respectable run for its money. GM knows that a I-6 is superior. My son's 2002 chev trailblazer has an I-6 gasoline 4.2L engine that has loads of torque, runs economically, and gives no problems. Ford and GM are operating under the principle that BS baffles brains. Whats new in this world, besides someone with an ulterior motive trying to take advantage of someone elses ignorance?

 

My Dad and grandpa both drove truck back in the day, and they both said the same thing.
Back then, Mack introduced a V8 design, and Cummins stuck with the Inline 6.
They both was telling me that on flat level ground, the V8 would really move quick. But when it came to a hill, The inline 6 would climb it very quickly and pass the V8.
Now, the times have changed and they can really both compete, but the Cummins will do better in the long run.
Ever really notice how simple things are on a Cummins compared to the V8's?
Sorry I cant really tell you why Ferd and GM went with the V8
Wheelo

 

Gm put an inline in their colorado/canyon trucks.

This is america, if 6 is good, 12 must be twice as good. V-8s have had some really good, market flooding cheap designs. Afterall, you can pick up parts for a 350 gm small block for little to nothing. But look at prices for a GM straight 6.
If your in the position of making a profit, would it be better to sell a $4000 V-8 at $5600 that will last 100K like other trucks or sell a $5000 I-6 for $5500 that will last 200K?

 

The first motor I ever saw was a straight 8 cylinder in an old Buick. Then Buick (or somebody) made a V8 to save space.


How about a straight 8 Cummins?

 

Okay, a few more thoughts here. First, Panterastk, the "reason" Ford has changed engines so much is not about reliability. If so, they did a real mis-step with the 6.0. The real reason was two fold - emissions, and refinement, not to mention, a desire to push out a bit more power.

The V-8 is not an inherantly bad design, even for a diesel. I would agree that it largerly depends upon your use and priorities. For me, I could utterly care less what others think about my truck, so bragging rights make zero differance to me. On the subject, I have observed BMW V-8 common-rail diesels which use two small VGT turbos (Varible Geometry Turbo), one at each cylinder bank. This is a considerably more efficient design than the Y-pipe up to the large single turbo on the Ford product. Plus, the heat concentration under the windshield - next to the firewall and dash and all the associated electrical parts, will not bode well for long-term reliability for vechiles so equipped.

The V-8 can be a bit smoother in certain situations, but it nearly always consumes more fuel and is more complex. Not to mention, it's difficult to work on. I prefer the I-6 engine, even with a gas unit.

 

Have you ever seen the inline six gaser that ford made? They last forever, get good milage, and look remarkably like the CUMMINS. 5 bearings to 7/ 5->8 -or 7->6. Its a matter of physics my good sir.