3 cyl. vs 4 cyl.

[_RaT_]

Actually another error in this thinking is the "cost to build" and the "retail sale sticker price" are connected on a sliding scale. The 24v is the best light truck diesel on the market (and I drive a Ford). If you have a hot item you can price it at what the market will bear, not what it costs to make.

Last time I went looking for a new truck*, the option for the diesel be it Cummins or International or the Duramax, the price was nearly identical. Both added about $5000 to the price. Since I am not privledged to the cost build spreadsheet of any engine manufactuer I cannot not assume the Cummins is simply cheaper to build because it has 2 less cylinders nor would I assume that they make more dollar wise per engine because they can sell it for the same price as a competitor with 2 more cylinders. It could be true, but I think it is all speculation at this point.

* After seeing the price I decided to buy a house instead. How can you buy a new truck today?

 

[_RaT_]

Not so.....you have answered your own question. Cummins engine is a known trade name for quality, power, and Durability. So they charge more for the product. Just as a Perkins is known for the same and charge more. Money truly is the real difference in 3 vs 4 engines. Who can produce what the cheapest. Thats why they are almost all foriegn engines....cheaper to produce.

I have? Help me through it. How much exactly does the Cummins cost to build say versus the International? A Perkins 3 versus a CAT 6

 

[john_bud]

Seems like a no brainer..... On small diesel engines of near equal displacement, 3 cylinders seem to for the most part, out perform most 4 cylinder versions, outlast them, operate considerably more efficiently. and according to SOME, they're even cheaper to produce.

We can thrash out all the "armchair quarterback" theories, but let the FACTS speak for themselves. In EVERY case where a 4 cylinder was dropped from a product line in favor of a 3-cylinder, there was no debating the fact that the 3-cylinder was a dramatic IMPROVEMENT over the 4 cylinder model they bumped. (Maybe in the sense that offering a better tractor will SELL more tractors, it was an economic move on their part...)

Let's talk gas engines too while we're at it. The Continental "Red Seal" 4 cylinder engines used in all those old Fergies was dropped in favor of a 3 cylinder PERKINS gas engine in the late 1960's. While that was a purely economic move, it resulted in a very reliable and efficient motor. Anyone who's used both will jump at the 3 cylinder version over the very respected 4 cylinder models. (More low end torque at the same HP rating)

If someone wants to rationalize the industry wide use of 3 cylinders as an economic move, so be it. To me, it WAS an economic consideration....... My money needed to be spent on the best possible choice of tractors.

And for the record, when Massey Ferguson made the switch FROM "Standard diesel" 4 cylinder engines in 1958, to the 3 cylinder Perkins, cost of the tractor INCREASED around 20%. It wasn't an economic move. It was for the sake of a better, more efficient tractor.

I own a Massey Ferguson 150. It has the AD3-152 Perkins. When this tractor was tested by the folks at Univ of Nebraska, it was the most fuel efficient tractor ever tested to that date. (HP/hrs per gallon) It held that status for more than 20 years......until ANOTHER 3-cylinder tractor using the SAME MODEL OF ENGINE edged it out. Caterpillar now owns Perkins. (Was owned by Massey Ferguson from 1990 until the recent sale) They STILL produce an updated variant of that same engine. It's hard to justify producing the same configuration of engine for 50 years if it WASN'T anything more than a "cheap engine". To withstand a test of time such as that, it had to be a GREAT little powerplant.

I've now owned a gas powered Ford 3000 and a diesel 3000. Both are 3 cylinders. They WERE 4 cylinder motors BEFORE 1965. The 3 bangers will work circles around the earlier 4 bangers.

So... From my point of view, those little 3 poppers are BETTER as well as cheaper. Again, a no brainer.

Farm,
So, which engine do you like better? It's so hard to tell from your post (hee hee!).



Someone else posted that it was the Asian invasion that brought the wealth of 3 cyl engines over here to replace 4 cyls. Not so! Remember back to the "Johnny Poppers"? with 2 cyl engines? Or all of the 3 cyl ones from the 50's and 60's? I bet you could store all of the Asian tractors sold in America in 1960 inside a large barn! Not much of a invasion at that point!

jb

 

[Farmwithjunk]

Farm,
So, which engine do you like better? It's so hard to tell from your post (hee hee!).



Someone else posted that it was the Asian invasion that brought the wealth of 3 cyl engines over here to replace 4 cyls. Not so! Remember back to the "Johnny Poppers"? with 2 cyl engines? Or all of the 3 cyl ones from the 50's and 60's? I bet you could store all of the Asian tractors sold in America in 1960 inside a large barn! Not much of a invasion at that point!

jb

Like so many of us, I've always obsessed over caring for the wants and needs of my family. A wife and 3 children can get rather expensive on an average working mans salary. My farming addiction helped, but not as much as the hours invested should have returned. To further the cause, I bought and resold used tractors and implements. Over the years I've dealt with numerous brands, models, configurations, and colors of tractors. 2, 3, 4, 6, and even one 8-cylinder tractor. I've had my favorites in all the sizes and brands. However, I've always had a soft spot in my heart for the very first NEW tractor I owned. That 150 Massey I talk about all the time. And that isn't just because it was the first NEW one.

The 150 would probably make the Energizer Bunny back down for a rest break. It's been stone reliable, cheap to operate, even relatively cheap to buy originally. Add that to the fact that I just plain ol' like to run it and you have a good idea why I like it so.

In the 60's and 70's, when the U S tractor market was gung ho after BIG HP, the British Isles were still buying smaller (50 hp and down) tractors in record numbers. At that point, 1 out of every 4 tractors sold in England was a 135 Massey. (MF 165, Ford 3000, and 4000 were next in the pecking order) They were just that much better than the competition. If you ask 10 former or present 135 owners why they liked their Massey, you can rely on the fact that the word PERKINS will appear in the first couple sentences.

I can't recall a time when there WASN'T a few 3 cylinder engines on the market, yet I can recall a time when there wasn't any "asian imports here in the states.

Once you go past the 50 hp range, I don't know of any successful 3 cylinder diesels. And into the 75 to 100 hp range, make mine a 6 banger. But in those "little engine" tractors, gimme my Perkins diesels. 50+ years of excellence is enough evidence that they did it right.

 

[SkyPup]

Four of our tractors are three cylinders.

 

[RobJ]

I believe that was what he was saying.. more, and less intense power pulses should = a smoother run.. etc.

soundguy

This was the original quote...

Don't overlook the fact the 4 cyl has a single plane crank and the 3 cyl has a 3 plane crank. The 3 cyl will be more inheritly in bal. All else being equal, the 4 cyl will have more but less intense power pulses.


Maybe I did misunderstand, but I read it as the 4 cylinder crankshaft has 2 journals up and 2 down, the 3cyl has 3 journals spaced out. I just looked at one of my head gasket replacement pics and the 3 are spaced around the circle (so to speak, in my pictures I have one piston at the bottom, one in the middle and one at the top of the strokes). So in his statement the crank itself it sort of balanced out, and that makes perfect sense. I just don't think that has a lot to do with it, all cranks I've seen have counter weights anyway, otherwise the engine would shake itself apart. As someone mentioned, 2 is smoother than a single, 3 better than a 2 cyl and so on.

Rob

 

[RobJ]

Last time I went looking for a new truck*, the option for the diesel be it Cummins or International or the Duramax, the price was nearly identical. Both added about $5000 to the price. Since I am not privledged to the cost build spreadsheet of any engine manufactuer I cannot not assume the Cummins is simply cheaper to build because it has 2 less cylinders nor would I assume that they make more dollar wise per engine because they can sell it for the same price as a competitor with 2 more cylinders. It could be true, but I think it is all speculation at this point.

* After seeing the price I decided to buy a house instead. How can you buy a new truck today?

I can agree to agree with this. I haven't priced the big 3 but if you see them close to the same price then I would call that a marketing thing.

Since I have a Ford I hear more about the PSD, last I looked the I-6 24v cummins was still a fairly plain engine, inline injection system, turbo, straight 6. It is JMHO that this engine is cheaper to build than the International PSD and the Isuzu Duramax. It is amazing what they get out of that engine with little changes over the years. I wish I had the 24v.

Rob

 

[balper]

Once you go past the 50 hp range, I don't know of any successful 3 cylinder diesels. And into the 75 to 100 hp range, make mine a 6 banger. But in those "little engine" tractors, gimme my Perkins diesels. 50+ years of excellence is enough evidence that they did it right.

We have here a company offering 80 HP with a Turbocharged PERKINS 3 cyl. engine. I've once seen them on a field show and the poor NH dealer who was in with a 90HP+ tractor was obliged to say something in the line of "wonder how they did it" and leave.
I believe that that this engine business is switching from bigger = stronger to some different perspective. Just like we once thought Japan made crappy copies of our brands (some 30 years ago I reccon). Some of us now feel the same about 3 cyl engines. hard to say anything but I'm proud with my 3 cyl.
Thank you all for the great posts!

 

[Mickey_Fx]

This was the original quote...

Don't overlook the fact the 4 cyl has a single plane crank and the 3 cyl has a 3 plane crank. The 3 cyl will be more inheritly in bal. All else being equal, the 4 cyl will have more but less intense power pulses.


Maybe I did misunderstand, but I read it as the 4 cylinder crankshaft has 2 journals up and 2 down, the 3cyl has 3 journals spaced out. I just looked at one of my head gasket replacement pics and the 3 are spaced around the circle (so to speak, in my pictures I have one piston at the bottom, one in the middle and one at the top of the strokes). So in his statement the crank itself it sort of balanced out, and that makes perfect sense. I just don't think that has a lot to do with it, all cranks I've seen have counter weights anyway, otherwise the engine would shake itself apart. As someone mentioned, 2 is smoother than a single, 3 better than a 2 cyl and so on.

Rob

Since you are quoteing me. The inherient bal of a multiplane crank and the reaction to power pulses are not the same thing. Single plane cranks are not as smooth as multiplane cranks. Some auto 4 cyl engine have counter rotating weights to help improve the smoothness of the engine in addition to the counterweighted crank.

If you like do a search on single plane cranks. Here are a couple excerpts from various sites.

From Jag on their new V8.
"Purpose designed four valve V8 racing engines use a single plane crankshaft (like an in-line four cylinder) to obtain evenly spaced firing impulses along each bank to allow for optimum exhaust tuning, the downside being that the engine shakes laterally because of unbalanced forces"

From Truth about Cars. This site is biased towards V8's
"In contrast, inline four cylinder engines are inherently unbalanced. Because of the geometry of the crankshaft and rods within the engine, fours shake in both the horizontal and vertical planes. There’s only one way to mitigate the effect: add unbalanced shafts to create counter-vibrations."

From United States Patent 4974449
"A new balancing procedure for dynamically balancing the crankshaft and reciprocating parts overcomes the vibration forces produced by the high moments of inertia inherent in reciprocating engines with a single plane crankshaft"

This isn't no big thing for me and not trying to raise a fuss. Just pointing out other factors to consider.

 

[Joe1]

Regarding cost to build vs price, we don't know if Cummins can build their 6 cheaper than the GM V-8 or the Ford V-8. I don't have a problem if the can build it cheaper and still sell it at the same price. That's just the free market at work. What I do know is that we want all three companies to make a REASONABLE profit so they can stay in business, stand by existing products and improve them for the future with some of that reasonable profit plowed back into R & D.

IMO it would stand to reason that all things being equal (which they usually are not), it would be cheaper to build a 3 cylinder engine vs a 4 cylinder simply because of fewer parts to manufacture and less assembly time installing those fewer parts.

Bottom line is it's still academic.