3320 In the woods?

[orlo]

All the specs do state the larger displacement. Also my dealer stated the same fact.
Regarding the 3203 they 'cheat' a little. The rated speed of all the 3x20 series is 2600rpm EXCEPT for the 3203 which they rev a little higher to 2800rpm.
That's how they get that extra HP out of the same block as the 3120 they make it peak 200rpm higher. Also note that the 3320 rated speed is it's maximum speed (for the operating range). Also even though the block sizes are the same, the engines in the 3203 and 3120 are different according to different Yanmar engine part #'s. (3TNV84 vs 3TNV82A).

 

[rockyridgefarm]

3120 - 3tnv84
3320 - 3tnv88
3520 - 3tnv84t
3720 - 3tnv84ht

the 3320 is larger displacement due to a larger bore size. (88mm vs. 84mm)

 

[papafoxtrot]

3120 - 3tnv84
3320 - 3tnv88
3520 - 3tnv84t
3720 - 3tnv84ht

Just flat out seems strange to me why JD would switch an engine configuration in the middle of a model line. I'm sure the block casting is probably the same though they bore it larger. I even get how the bore increase would get them the extra HP they were after, but there are so many other variables an engine manufacturer can play with today to get ponies out of an engine that having to stock two different sets of pistons, rings (even blocks) is a bit baffling, that's all.

 

[rockyridgefarm]

In the TEN series there were three engines.

3TNE82A
3TNE84
3TNE88

So, actually the TWENTY's have reduced the parts.

Isn't it funny how we will pay more for a bigger bored version, with almost no additional cost to manufacture?