is there any advantage to four cylinders?

[4cylinder]

I have a B3030, and comparing say to equivalent or even larger tractors by Kubota and John Deere, it is the only one with four cylinders — most others have three. Sometimes I think the motor is a little underpowered, since I sometimes have to shift it from H to M to get up a moderate grade.

 

[Barnboy]

Ive never had any power issues with my B3030.The B3030 is a high horse power to weight ratio tractor.I didnt think anyone would ever have a lack of HP issue.That was on of the reasons i chose the 3030 over the 2630. I do live on flat land. I'm currious about the 4cyl vs 3cyl .

 

[ronjhall]

My B2910 (B3030 is newer model) is the same way. Especially if I have the BH on. Instead of shifting to M. Try letting up on the HST pedal. This will slow tractor down but should allow tractor get up hill without changing gear.

 

[NewToy]

I have always wondered the same thing about 3 or 4 cylinders. May I suggest posting the question in the "Owning/Operating" forum unless you are looking for a Kubota specific answer as opposed to the general operational differences in these two powerplants.

John

 

[browns40]

Good one,

Heard a few schools of thought on cylinders:

--More is better: better distribution of forces & wear over a larger # of cylinders (i.e. 1000 hours is 333.3 on a 3 cyl per cyl. versus 250 per cylinder on a 4)

--Bigger is better: larger pistons (with the same displacement ) create more torque

-- multiple of 3 are best: 3, 6, 12 sequence is a natural configuration to avoid vibration

I have no idea, but have heard more complements on straight 6 cylinder engines longevity I think... so I would infer the 3 offers a similar benefit... time is the only test I guess.

 

[_RaT_]

Good one,

Heard a few schools of thought on cylinders:

--More is better: better distribution of forces & wear over a larger # of cylinders (i.e. 1000 hours is 333.3 on a 3 cyl per cyl. versus 250 per cylinder on a 4)

--Bigger is better: larger pistons (with the same displacement ) create more torque

-- multiple of 3 are best: 3, 6, 12 sequence is a natural configuration to avoid vibration

I have no idea, but have heard more complements on straight 6 cylinder engines longevity I think... so I would infer the 3 offers a similar benefit... time is the only test I guess.

Interesting. My Kubota L48 was a 4 cylinder. My current Kubota L3830 is a 3 cylinder. Neither is noisier or quieter then the other. Neither has more or less vibration then the other. Both have exactly the same displacement per cylinder. I'll take a larger cylinder displacement 3 over a smaller cylinder displacement 4.

 

[rdsaustintx]

Heard a few schools of thought on cylinders:

--More is better: better distribution of forces & wear over a larger # of cylinders (i.e. 1000 hours is 333.3 on a 3 cyl per cyl. versus 250 per cylinder on a 4)

--Bigger is better: larger pistons (with the same displacement ) create more torque

-- multiple of 3 are best: 3, 6, 12 sequence is a natural configuration to avoid vibration

Just to be contrary on a weekend. I went to a different school

An hour is an hour. For a given rpm, the linear feet of piston travel per cylinder are the same. So there is more wear with more cylinders, simply because there are more parts with more surface area. Mutli-cylinder engines (at a given displacement) also generally spin faster.

Bigger is better when it comes to displacement, but larger pistons with the same *displacement* mean less stroke. That makes higher revs possible for more horsepower, but with LESS torque. Maybe you meant bigger pistons with the same *stroke*, which means more displacement?

For inlines, 6's can be harmonically balanced much easier than 3's or 4's. (V's are easier to balance, esp. with four or more cylinders).

More cylinders at the same displacement means smaller combustion chambers, a natural disadvantage in diesels (indirect injection).

Don't get me wrong -- I earnestly love my little 22hp 3cyl, but it vibrates as much as any motor I have ever seen.

I gotta agree with Rat.

Russell in Texas

 

[browns40]

Good points,

Again, as I said, I have no idea so you're not being contrary at all, just contributing insight to the discussion...

Those are just some points I've heard discussed when talking # of cylinders...

Hopefully some owners/mechanics/engineers who have seen both can attest to what they are seeing inside the motors they're familiar with...

 

[rdsaustintx]

Gee, hard to troll against a guy in an Elmo suit **tickle tickle**

I have a couple of mechanical engineering degrees, but the cylinder wars I recall best were from motorcycle road racing in the early 60's. Honda went rather extreme.

They successfully raced 6 cyl (inline) bikes. Pistons the size of nickels and redlines around 25,000 rpm! Then Honda got out of racing and water-cooled two strokes took over. When I sold my last Ninja (1992) superbikes were water-cooled four strokes with outrageous power/weight and the problem was making them stick to the ground. I'm sure they are wheeled rockets by now.

Stuff like hydraulics and tractors are more interesting these days. At my age I'd rather roll a TLB at 2mph than graze a guardrail at 200mph (pretty lame attempt to correct for obvious topic drift).

Back to my box blading,

Russell

 

[California]

Here are a couple more considerations regarding cylinder configuration:

Above a certain number (5 cylinders?) the crank and the entire driveline are under continual tension, since there is always one cylinder that is within its power strike. This must be easier on the driveline, and I think explains why a six cylinder sounds so much smoother than a four cylinder.

Also, re the 60's Hondas- The old British motorcycles with two cylinders ran them in tandem so there was one power stroke per 360 degrees of crank rotation. They pumped oil out the breather like mad (due to the constantly changing crankcase volume); this was part of the chain oiling system of that era.

Then along came the two cylinder Hondas. Their crankpins were 180 degrees apart and the two cylinders fired 180 degrees apart, then nothing for 540 degrees of crank rotation. I'm sure this better crank balance was one element that allowed much higher rpm's. They sounded 'funny', but they buried the British bikes in about a decade.