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Hi All,

I'm looking at various SCUTs and I've got a friend who swears by 4 cylinder engines. He thinks that 3 cylinder engines are bound to be imbalanced, and as a result, not last as long as a 4 cylinder.

It seems like all the small SCUTs use 3 cylinder engines, and I thought these engines lasted practically forever.

From the searching I've done, I can't find anybody who has actually experienced issues with a 3 cylinder engine. Just people who, like my friend, say "it's 3 cylinders, how could it be balanced!? It will break sooner, I'm sure."

Is there anything to this concern? Should I pinch my pennies until I can afford a larger CUT that's got a 4 cylinder?

-Josh
 

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Jb, 3 cyl has no more vibration issues than any other engine. Look at the 3 cylinder Kawasaki motorcycles of the 70's, and they were high revving 2 strokers. No problems going with odd # cyl's. Volvo, Audi and GM are currently using 5 cyl engines in their vehicles and have for several years. I can tell you from real world experience you have nothing to worry about.
 

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3 cylinders have been around for years without problems. The only issues i see with mine is it's lop sided and heavy on the right side and you can see tire tracks on the right and non on the left and the seat slopes to the right a little:biglaugh::biglaugh: slkpk
 

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Sure; 4-cylinders are better than 3 . . . and 5 are better than 4 . . . and 6 are better than 5 . . .

Tell us about that 45-cylinder tractor you finally purchased and will last forever. :)

Three cylinders are a time-proven, economical, stellar-performing package. There is a reason most of the SCUTs and CUTs are so powered. :)
 

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While its true that a 3cyl will be less naturally balanced than a 4cyl, thats why they have counter balance on the crank. Ask your buddy if his truck is a "V" configured engine? If so, according to him, they they shouldn't last nearly as long as a 3cyl because they are horribly balanced engine with very uneven forces on the crankshaft.
One of the best engines out there for natural balance is actually an inline 6 or opposed engines. (huh, wonder why most of the the bigger deisels are inline?.......) ;)

Brad
 

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These 3 cylinder engines are work horses and warriors. If well maintained they will most likely out live the tractor they are in! Thats why if given a choice between gas and diesel... I got to have the diesel:trink40::trink40:
 

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If inline 6's are the most 'balanced' engines, then 3 cylinders would be better than 4 cylinders. 1/2 (even) vs. 2/3 (odd)

3 cylinders have been around for years without problems. The only issues i see with mine is it's lop sided and heavy on the right side and you can see tire tracks on the right and non on the left and the seat slopes to the right a little:biglaugh::biglaugh: slkpk
Move the seat 2 inches to the left, you should see a definite improvement. Unless you have a lazy left eye, then all bets are off.

:sidelaugh:sidelaugh
 

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Because the engine is inline, even or odd number of cylinders don't make a difference. Mercedes has a 5 cylinder inline diesel; GM has an inline 5 gas engine. What about the zillions of single cylinder engines out there? Supposition without education leads to misconception.
 

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My 64 gas model 430 , 74 model diesel 820 & the 07 5303 all have 3 cylinders, ran the 64 for 12 years, the 74 for 14 years w/o a single engine problem.
I'm still wondering why the 07 has to have a Turbo, the older unit's ran just fine without one.
The 96 MF 283 had a 4 cylinder, one powerful tractor that was just to big for my needs, ran it for 2 years before i got the 5303 & back to the green/yellow that i'm familiar with:trink39:.

Ronnie
 

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3-cylinders are great, either gas or diesel. My all time favorite engine ever was a 3-cylinder gas in an old John Deere 1020. It was smooth, powerful, and had an exhaust note that was closer to music than any engine I have ever heard. Geo Metros also ran 3-cylinders frequently, and while they are definitely underpowered, they do withstand a lot more abuse than people give them credit for. The only complaint I have about 3-cylinder diesels is that they don't weigh enough to hold the front of the tractor down.
Which is why you need to get a FEL with your tractor. :)
 

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"it's 3 cylinders, how could it be balanced!? It will break sooner, I'm sure."

for an in-line engine, that statement is a complete myth.
if it was a V configuration, with one cylinder on one side, and 2 on the other, it would be true. But what moron would design a dumb engine configuration like that?....

the issue with strange vibrations are related to the angle-offset between the strokes. all you need to do is make sure the 360 degree rotation is equally split between all the strokes (one for each piston), and you're done. A 3 cyl engine will be spaced 120 degrees apart. 4 cyl. will be 90 degrees... etc...

diesel engines are build very heavy to deal with the high compression and low RPM / high torque output.... once you pile on so much cast iron into the engine to deal with all that, the vibration issue becomes irrelevant...

easy....
 

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No problem with 3 cylinders as far as shake is concerned. My former excavating contractor had a JD backhoe FEL with a 3 cylinder diesel that was OLD when I met him in 1983 or there abouts. That tractor is still in use on his property today, although he is long retired from doing commercial work. Still runs as smooth as it did 30 years ago.
With that and a CAT D4 loader he could do a lot in a short amount of time.
My own 3 cylinder Yanmar is as vibration free as another friends '29 Packard roadster. He actually sets a stemmed wine glass, filled to the brim, on the flat surface of the head and runs that thing with out spilling a drop. That's a straight 6, BTW.
 

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My 64 gas model 430 , 74 model diesel 820 & the 07 5303 all have 3 cylinders, ran the 64 for 12 years, the 74 for 14 years w/o a single engine problem.
I'm still wondering why the 07 has to have a Turbo, the older unit's ran just fine without one.
The 96 MF 283 had a 4 cylinder, one powerful tractor that was just to big for my needs, ran it for 2 years before i got the 5303 & back to the green/yellow that i'm familiar with:trink39:.

Ronnie
I'm guessing that the turbo gets better fuel economy for the same hp engine. Say you take a non-turbo engine that produces 30 hp, a smaller turbo engine that would be 25 hp or so if it was non-turbo can deliver the same 30 hp with the turbo while using less fuel than the 30 hp non-turbo engine.
 

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Discussion Starter #15
2008 SC2400 with 205 hours, loader and 60" mid-mount mower--dealer is asking $9975.

Is John Deere 2305 the same Yanmar tractor as the Cub Cadet 2305? If they're both the same tractor, then I'm not sure it's worth it to pay for the green paint.
 

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2008 SC2400 with 205 hours, loader and 60" mid-mount mower--dealer is asking $9975.

Is John Deere 2305 the same Yanmar tractor as the Cub Cadet 2305? If they're both the same tractor, then I'm not sure it's worth it to pay for the green paint.
Not sure but it's interesting how they both have the same number and then the paint is largely the only difference.

Meanwhile I have a cousin who bought an 18hp Yanmar grey market with a loader and small hoe, 2 cylinders. I believe he paid way too much for this 1980's vintage tractor-about $8000-but it is a a really good machine and has servrd him well. But prices here, in Connecticut, are way more than down South. Example EX3200 here with FEL and Hoe $27,000+6% tax. In Tennessee same tractor, same attachments $19,999. Oh and no tax but about $1000 for delivery (about a 2000 mile trip both ways).
 

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Discussion Starter #17

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About 3-cylinders...

Buy one, love it, maintain it, enjoy it. I'll bet if you never popped the hood on your new (insert brand here) tractor, you'd never know if it had 3 or 4 cylinders.

Put your energy into identifying your tractor needs, pick a color, work your best deal (this may dictate color also), and enjoy whatever it is. The least of your regrets will be # of cylinders...Your only regret may be that you should've gotten the next size up with MORE POWER!!!!

Seriously, enjoy the tractor picking process and don't sweat the number of cylinders.

Enjoy! (remember to write back and tell us what you got!)

Tim

:fing32:
 

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Well, in actuality a three cylinder is balanced both dynamically and statically better than a four cylinder. A four cylinder engine is two two cylinder engines and nothing shakes like a two cylinder engine - no matter how the crankshaft is configured they have an inherent imbalance. Balance shafts were developed with the four cylinder in mind. A three cylinder is balanced in sixths meaning that it has half again more balance points than a two or four cylinder. Your buddy is wrong - the four cylinder engine is more out of balance than the three cylinder diesel.... The main reason for the development of three cylinders was for diesel engines since they have greater combustion bursts than a similar gasoline engine - there is more energy in diesel fuel....
 

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3 cylinders is also the ideal number for a turbo application. The exhaust pulses line up just right and provide a nice flow into the turbo and increase turbo efficiency.
 
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