3 cyl vs. 2 cyl?

[nazbom2]

Speaking of # of Cyl's what about 1 cyl vs 2 cyl i.e. Single vs. V Twin? I go back to the anecdotal argument that 1 cyl produces more torque but less HP due to larger mass of 1 piston displacing same/similar amount. Would this be tru for 2 vs 3 cyl?

 

[California]

I think that question gets off into the realm of theory rather than anything the operator can experience. For smoothness, the more cylinders the better. For absolute economy, the fewer the better due to heat radiation loss. (Wasn't the Geo Metro a three cylinder engine?).

Aside from the racket, Yanmar's twins are never going to feel smooth because of the firing order. One piston rises while the other descends. This keeps the crankcase volume approximately the same throughout the 4 cycles (unlike the old British motorcycle twins with both pistons rising side by side simultaneously) but it means the cylinders fire 180 degrees apart then nothing happens for another 540 degrees of crankshaft rotation. Galump .... galump ... galump .... . Forget smoothness.

 

[Dadof3]

Ain't nothin like the sound of triple at 1900 rpm!

 

[nazbom2]

Right I agree on the course correction and apologize! Anyway I love my two cylinder and I guess ignorance is bliss haveing never owned a 3 cyl so am happy with my "smooth" running 2 cyl Yanmar!!

 

[Egon]

Engine balance - Wikipedia, the free encyclopedia

A little information on engine balance.

 

[Car Doc]

Fuel economy is excellent for either type, with an insignificant edge to the twin cylinder. There really isn't much to choose as fuel consumption goes. All of them impress me, especially every time I run my 17 hp gas engine riding mower.

Yeah isn't that the truth I only can speak on 3 cyl though and it is real smooth and quiet especially when its warmed up good. My wife has a 23hp v-twin 50" garden mower it uses 1/2-3/4 tank or about 3 g to do the 2 acres here at the shop.

My 3810 on the other hand is about 90 ci and 38 pto hp supposedly and will do it on less than a gallon its not even real easy to measure with my stick only running it that long and takes me 45 minutes-1hr. fwtw

I would have to run in high gear to catch her but besides that I can do it quite a bit cheaper albeit a little slower.

 

[deepNdirt]

Speaking of # of Cyl's what about 1 cyl vs 2 cyl i.e. Single vs. V Twin? I go back to the anecdotal argument that 1 cyl produces more torque but less HP due to larger mass of 1 piston displacing same/similar amount. Would this be tru for 2 vs 3 cyl?

I've had experience in owning/operating a 1 cyl. diesel compact tractor, and I can assure you the power/torque is somewhat different than that of a multiple cyl engine, a single cyl engine has low end torque from lower range RPM's, as where a multiple cylinder engines will require revving up into higher range of rpm's to achieve equal torque, when I sold my 1 cyl kubota and got the 2 cyl yanmar I had to learn over again where to set the throttle,and what gear to run in, in comparing the 1 cylinder Kubota I could run it in low gear 3rd. at around 1400 rpms to pull the harrows, The ym-1700 needs to run in 2nd. gear high range at 1800 to pull at the same rate, if I were to use the 3rd gear low of the yanmar I'd have to rev it into the 2000+ range to pull at the same rate ultimately working the engine much harder,
I really have'nt found much use for the lower range gears ofthe ym-1700 , the tractor is much too slow in the low gears, But on the other hand so was the 1 cyl kubota. I could set the kubota in 1st low and actually walk faster then it would move, in fact you have to watch it closly to tell it was moving at all,

 

[winston1]

Somebody once said the only thing you would use the creeper gear for on these Yanmars is so you could watch the seasons change while putting it in the barn.

 

[pesaventoc]

Somebody once said the only thing you would use the creeper gear for on these Yanmars is so you could watch the seasons change while putting it in the barn.

I asked my 86 year old mother in law if she would like to run my yanmar. To my surprise she said yes. Talk about good use for the creeper gear!!!

 

[Egon]

I've had experience in owning/operating a 1 cyl. diesel compact tractor, and I can assure you the power/torque is somewhat different than that of a multiple cyl engine, a single cyl engine has low end torque from lower range RPM's, as where a multiple cylinder engines will require revving up into higher range of rpm's to achieve equal torque,QUOTE]


Wouldn't the engine design be the big factor? Note all the small single cylinder engines running at 3600 RPM.

Then consider an older Lister Twin maxing out at 600 RPM.