JD 3520 Yanmar power vs size

Fork Horn J · Aug 27, 2009

First Post

I am getting ready to purchase a 3520 with gear transmission. I see that the 91.5 ci Yamnar seems small for it's HP output. Should I worry about this? why is the 3320 equiped with a 100 ci vs the 3520 and 3720 that get there pwer from the 91.5? Most other manufactures show larger displacements up to 141 ci for this HP range.
Is the direct injection better than the trottle body in general for these machines?
Should I even be worried. I think my american ego is kicking in...MORE, BIGGER, BETTER!!!!!!!!!!!!!!

Thanks for any advice!

hilld · Aug 27, 2009

The 35 and 3720's are turbo charged, while the 31 and 3320's are not. Not everything is cubic inches.

John_in_TN · Aug 27, 2009

The larger displacement, non-turbo engines have more grunt at low rpm but at higher rpm the 3520's turbo is able to squeeze more work on less fuel. If you like to putter around at low engine rpm then you will probably be better off with a large displacement, non-turbo machine. If can keep the rpm up, then you can do the same work on less fuel.

I went from a 4200 gear (26 hp) to a 3520 hydro (37 hp). I often puttered around with the 4200 at low rpm. The 3520 is sluggish below 1500 rpm (may be partly due to the hydro) but even at 1500 to 2000 rpm it uses less fuel than the 4200 did puttering. At pto speed the 3520 is night & day stronger and still just burns slightly more fuel than the 4200 did (at pto speed).

For me, it took some getting used to, but I am very pleased with the 3520.

Fork Horn J · Aug 27, 2009

Thanks for the info. The only reason that I want to go to the 3520 is the extra HP to the PTO. I guess I was just concerned about the old smaller engine working harder to get the HP. I guess if this was an issue I would not have to look very hard to find out about it!

Mickey_Fx · Aug 27, 2009

FYI, no such thing as throttle body injection on a diesel engine. You also won't find a throttle either. Diesel engine speed controlled by amount of fuel injected. Air intake is not restricted by anything other than what the air filter does.

GreatWhitehunter · Aug 27, 2009

As for power to weight ratio, all the 3000 series will run out of traction before hp. I've never overpower my 3320 with either pto attachment or ground engagement. I've got filled rears and r4's. Not sure what r1's would yeild, it doesn't seem to be a real popular tire for most of us. The only place I can see any real need for the hp is pulling a pto powered attachment (like a large mower) up hill. And as most will tell you the narrow width of the 3000 series is not the best option for hill work. That said I operate mine on inclines of over 45degree's in a forward+reverse direction.

Matt