3 cyl vs 4 cyl?

Anonymous-0

Well-known Member
Is there much of a difference when working a 4cyl as opposed to a 3 cyl? I have a super c that I do loader work with, and I have a field cultivator that I till up our pastures up with (really sandy loose soil so it handles an 8 ft really well). All the newer equip has 3 cyl which I am sure is better for fuel economy and emissions, but if you had the same hp and the same conditions pulling the same plow, etc do the smaller motors have the same smooth "pull" that more cylinders have?

Maybe this is all personal preference...
 
I have a IH 484 with a 3cyl diesel and it runs as smooth as a electric motor. I had a case DB 995 and it was a 4cyl diesel buy 2 cyl would fire at the same time. The IH when one piston is TDC one is midway and the other is BDC.
 
Threes have less inherent vibration, and a bit less friction, but they are not dramatically superior.
Putting higher RPM on a 3 gives it the same pulses per minute that a 4 has. They are fine. If modern in the sense that they have electronic fuel injection (diesel or gas) and electronic ignition and engine management, those are superior in performance for those reasons alone. Jim
 
I would use the appropriate number of cylinders for the HP requirement. The newer engines will be 2,3,4,or 6 cylinders, the older ones were 2,4 or 6.
 
Typically the newer the tractor the higher the rpm. It is free displacement in the sense that it pumps more air, and makes resulting power. The wear factor is not important, it is usually not twice the RPM. Jim
 
How "modern" are your 3 cylinders? The engines made the last 10-15 years can hardly be compared to engines designed 75 years ago and built 60 years ago. Air flow, fuel injection, electronic ignition have all improved. Compare a Chevy 235 I6 (3.9 Liter) to a "new" Chevy 2.2 engine. Almost half the size with much more HP and torque and they both run on 87 octane.
 
My take on 3cyl vs 4cyl is you can have the same horse power but A 12 horse lawn tractor will not pull what a 12 horse farm tractor will. And these new compacks have to have 4 wheel drive to come close to pulling a disk or plow. The larger rear tire makes alot of difference. Just my 2 cents. Doug
 
(quoted from post at 16:29:36 12/05/12) How "modern" are your 3 cylinders? The engines made the last 10-15 years can hardly be compared to engines designed 75 years ago and built 60 years ago. Air flow, fuel injection, electronic ignition have all improved. Compare a Chevy 235 I6 (3.9 Liter) to a "new" Chevy 2.2 engine. Almost half the size with much more HP and torque and they both run on 87 octane.

Put that 2.2 into a '57 Chevy 60 series truck and see how long it would last.
 
I don't recall the 235 being much on durability. The babbitt bearings should be enough said on that topic.
 
(quoted from post at 15:28:51 12/05/12) I don't recall the 235 being much on durability. The babbitt bearings should be enough said on that topic.

Only the first few years used poured babbit bearings like the the 216 did. From 1955 on all the 235 engines had precision bearing inserts. The insert type bearings were also babbit but only a couple thousands of in inch thick. There superiority comes from the steel backing. The 261 engines didn't last so long in many of those trucks either but then running them at 4400 rpm at 55 mph could have been part of the problem.
 
No the 3-cyl engines are usually not as smooth & quiet as the 4-cyl. of the same size and hp.
 
> A 12 horse lawn tractor will not pull what a 12
> horse farm tractor will.

No, of course not, for two reasons:

a) Horsepower is speed times force and determines how fast a machine can pull whatever it is that it can pull at all. "Pull" (i.e., draft) is a measure of the maximum force the machine can exert and is limited primarily by what it weighs.

b) Farm tractor horsepower is what the machine actually delivers to the wheels. Lawn tractor horsepower is the most that the manufacturer was ever able get out of the engine on a test stand in the lab.

> The larger rear tire makes alot of difference.

Tire size matters, as does tread, but weight dominates.
 
I have run 2, 3, 4, 6, and 8 cylinder engines and even the old 2 banger JD's with the 77 degree offset would pull smooth. It is the fly wheel that smooths out the performance of the engine. The Perkins 3-cylinder diesels ran fine but not as smooth as a 4 or 6. By far the 6-cylinder engine was the smoothest in gasoline or diesel but it was a sound and feel thing only. The movement of the tractor was not affected by the number of cylinders.
 
My MH 253 is a 3 cylinder diesel, 4 wheel drive and was tested at 47 hp at the pto. It has 153 cu.in. At 152 cu. in. the Farmall H gets close to 28 hp on the belt. The Massey is far better than the old H. My Massey Ferguson will even outpull my M any day of the weeks. No contest.
 
wikipedia: "Horsepower is defined as work done over time. The exact definition of one horsepower is 33,000 lb.ft./minute.
Put another way, if you were to lift 33,000 pounds one foot over a period of one minute, you would have been working at the rate of one horsepower. In this case, you'd have expended one horsepower-minute of energy."

How much force (HP) is required to pull a two bottom plow through the soil.
How much force is required to get it moving?
How much additional force is required to keep it moving at a rated speed to the end of the field ?

Anyone with experience with horse pulling can give you one opinion on Horsepower, some teams can pull up to two times their combined weight, of course, this is only for ten feet or so, BUT I doubt they would be able to do it down to the end of a field.
So.... it all becomes relevant to how efficient an older tractor is compared to any newer versions.
Fuel consumption per hour, for sure, and how long they can continue without any break downs or stoppages.
I am a bit anxious to see how many modern tractors will last 80 years after performimg the same amount of work these old ones have.
I can imagine this same argument was had between father & son back when the first Regular tractor replaced the beloved teams of Percherons, or Belgians, then later when the new H replaced the F20 and so on through the decades.
Are the new tractors better ?? In some ways yes, but only time will tell.
 

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