mus302
Bronze Member
From reading around, the general opinion seems to be that the 3 cylinders are smoother but that the 2 cylinders have more torque than the same size 3 cylinder.
Comparison Powershift
- Thread starter rmully
- Start date
California
Super Star Member
- Joined
- Jan 22, 2004
- Messages
- 14,674
- Location
- An hour north of San Francisco
- Tractor
- Yanmar YM240 Yanmar YM186D
I have a YM240 (YM2000) 24 hp twin, and a YM186D (YM1510D) 18 hp 3-cylinder.
Pix: http://www.tractorbynet.com/forums/...ner-here-p1530591rym240-ym186d-intarpshed.jpg
The twin seems to have the same torque at any speed and the throttle is just to set how fast you want to do it. Think of how a Caterpillar seems to have useful torque down to nearly zero rpm. It's not *that* strong, but it has the same feeling as you run it.
The three-cylinder, in contrast, wants to be in the upper half of the rpm range to do anything useful. It is very apparent that its torque increases with rpm, and that it is pointless to push it hard below about 2000 rpm.
Pix: http://www.tractorbynet.com/forums/...ner-here-p1530591rym240-ym186d-intarpshed.jpg
The twin seems to have the same torque at any speed and the throttle is just to set how fast you want to do it. Think of how a Caterpillar seems to have useful torque down to nearly zero rpm. It's not *that* strong, but it has the same feeling as you run it.
The three-cylinder, in contrast, wants to be in the upper half of the rpm range to do anything useful. It is very apparent that its torque increases with rpm, and that it is pointless to push it hard below about 2000 rpm.
mus302
Bronze Member
California,
Since you have both a 2 and a 3 cylinder, how would you rate the difference in smoothness and noise between the two?
Since you have both a 2 and a 3 cylinder, how would you rate the difference in smoothness and noise between the two?
California
Super Star Member
- Joined
- Jan 22, 2004
- Messages
- 14,674
- Location
- An hour north of San Francisco
- Tractor
- Yanmar YM240 Yanmar YM186D
The three cylinder is nice and smooth. Like a tractor cousin to a Toyota.
My wife says when she is in the house while I am mowing she can hear it but it is a soothing, non aggravating sound.
In contrast the two cylinder is simply primitive. Each firing has a very harsh clank like striking a manhole cover with a heavy digging bar. Then imagine that at higher rpm.
The instantaneous sound level is so sharp and strong I think it can easily cause hearing loss, same as gunfire. This isn't the exhaust, it is the block or head receiving a heavy impact from the combustion causing a loud clank. Listen to the sound file at the extreme bottom of the page referenced from my sig, below.
These twins are famous for giving the impression that a rod bearing has been washed out and a rod will come through the block momentarily. It is unnerving to work with such a disastrous sound. 1100 rpm would be plenty for my stationary backhoe work (The PTO hyd pump doesn't draw much power) but I use minimum 1200-1250 to get it up to where it doesn't clank so bad. Then over 1800 rpm, it sounds like it will come apart at any second. Roading it at 2400 rpm sounds like horrible abuse, despite that the manual allows it.
They haven't made twins for 30 years. It is an excellent engine but I think this racket is why they retired it.
I recommend hearing protection. Also I feel bad that everyone within a mile, around the ridgetop on my side and the other side of the canyon, is annoyed by it. I hear several tractors in the neighborhood and there is only one that has the harsh clank like this one, and his is only at near-stall. The twins aint some wimpy homeowner lawnmower!
I love the 24 hp twin's torque, but downshifting the Powershift on the 18 hp 3 cylinder is about as effective, at least for mowing where its lighter weight is irrelevant.
I still need the larger tractor for its large capacity loader, and for earth-engagement work - box blade etc where its weight gives traction. They both have their place.
The twins are a great value for the money, and a 3 cylinder with Powershift capable of the same work is going to cost a lot more.
My wife says when she is in the house while I am mowing she can hear it but it is a soothing, non aggravating sound.
In contrast the two cylinder is simply primitive. Each firing has a very harsh clank like striking a manhole cover with a heavy digging bar. Then imagine that at higher rpm.
The instantaneous sound level is so sharp and strong I think it can easily cause hearing loss, same as gunfire. This isn't the exhaust, it is the block or head receiving a heavy impact from the combustion causing a loud clank. Listen to the sound file at the extreme bottom of the page referenced from my sig, below.
These twins are famous for giving the impression that a rod bearing has been washed out and a rod will come through the block momentarily. It is unnerving to work with such a disastrous sound. 1100 rpm would be plenty for my stationary backhoe work (The PTO hyd pump doesn't draw much power) but I use minimum 1200-1250 to get it up to where it doesn't clank so bad. Then over 1800 rpm, it sounds like it will come apart at any second. Roading it at 2400 rpm sounds like horrible abuse, despite that the manual allows it.
They haven't made twins for 30 years. It is an excellent engine but I think this racket is why they retired it.
I recommend hearing protection. Also I feel bad that everyone within a mile, around the ridgetop on my side and the other side of the canyon, is annoyed by it. I hear several tractors in the neighborhood and there is only one that has the harsh clank like this one, and his is only at near-stall. The twins aint some wimpy homeowner lawnmower!
I love the 24 hp twin's torque, but downshifting the Powershift on the 18 hp 3 cylinder is about as effective, at least for mowing where its lighter weight is irrelevant.
I still need the larger tractor for its large capacity loader, and for earth-engagement work - box blade etc where its weight gives traction. They both have their place.
The twins are a great value for the money, and a 3 cylinder with Powershift capable of the same work is going to cost a lot more.
Last edited:
California
Super Star Member
- Joined
- Jan 22, 2004
- Messages
- 14,674
- Location
- An hour north of San Francisco
- Tractor
- Yanmar YM240 Yanmar YM186D
I'm stuck in a hotel in DC, waiting for my daughter to get off work so we can take her out to dinner on our last night here.
Just for fun I started a new thread
Mowing: Big twin (YM240) vs little 3-cyl/Powershift (YM186D) - TractorByNet.com
showing my two tractors I described above doing some actual work.
Just for fun I started a new thread
Mowing: Big twin (YM240) vs little 3-cyl/Powershift (YM186D) - TractorByNet.com
showing my two tractors I described above doing some actual work.
mus302
Bronze Member
California,
That is interesting. I have never been on or even around a running two cylinder Yanmar.
That is interesting. I have never been on or even around a running two cylinder Yanmar.
MJPetersen
Veteran Member
I wonder if that is true of the smaller ones, say the 1300 vs 1301? it would be an interesting comparison.
Mike
Mike
Smoody
Platinum Member
having used both 2cyl and 3 cyl, you probably should be wearing hearing protection when running either...
2 cyl sounds better to me, 3 cyl sounds like a really loud lawn mower at high rpms.
2 cyl sounds better to me, 3 cyl sounds like a really loud lawn mower at high rpms.