JD-920 mo-co

went and looked at jd -920 again dealer has 2 one with rollers and one with impellers which is better I use a NH-488 now with roller dont know anything about impellers thanks cdv

I only sold the impeller machines around here. IF you are the type of fellow that will adjust things when crop changes then the impeller machine will work fine. IF you like to set something once and never look at it again then go with the roll machine.

The impeller will through put more hay faster than the roll machine. The impeller has a slight suction effect so in light hay they will pull the short crop back off the cutter bar better than the roll machine. Some time in short hay the hay will bunch up in front of the rolls and get cut several time and fall back off the front with a roll machine.

The impeller will pull a little harder than the roll machine will. IF you have many hills you want at least 100 HP on a JD 920 with impeller. IT takes a GOOD JD 4020 to pull one in hills.

IT all comes back to condition of the machines too. I would look at the turtles, that the knives hook to, real close. IF they are worn or cracked then you can easily spend a $1000 replacing the set. Check out how the cutter bar runs. Have the dealer hook them both up to a tractor and run them. The impeller machine should be quite when running empty. The roll machine will be a little noisy at the rolls but not much more. IF you think you would like the roll machine better really check out the rolls close. There should not be any cracks or chunks out of the rubber on them.

On a disk mower the rolls can get damaged easier because there is no sickle to get plugged. So guys tend to mow through rougher stuff than they ever would even try with a sickle machine.

Either machine is a good unit just decide which one you think would serve you best. IF your mowing mostly grass hay I would not even think about the roll machine.

I have a 920 impeller I love it no plugging in super thick crop we hardly ever change setting on impeller

Its funny you say that, I can go as fast with a roll machine through big hay as an impeller machine.

I had a 920 disc cutter with the impellers and I loved it. I used a 2950 JD. 85hp. and it handled it real well. Jim

True, the impeller machine will cut just as fast as you can go. You do have to adjust depending on crop. Might be field to field. You know your fields and how much I needs.

I would agree that you need a good machine. I ran it on a 4020 one time and won't again. If the prairie is tall it is just too much for the machine, I feel. I use it on a 4440. The tractor doesn't know it is back there, but I think that's not as hard on a machine as the chugging that the 20 would do when it got thick. Plus, the 40 has a/c!

Stuart: I mowed some 7 foot tall rye grass with the JD 930 impeller machine that I owned then. The rye was a neighbor's. HE had a JD 920 roll machine and we could not get it to take the rye through. It would plug the rolls if you went over 2-3 MPH.

Some guys are going back to roll machines. I have had good luck with the impeller machines and really do not want to go back to rolls.

Some day when it goes bang on the 4440 you're realise why they don't recommend more than about 90 hp on a 10' mower.

Rod

JD Seller, what is the correct setting on the impellers for cutting alfalfa?

I have a 946 and where you have the board set for alfalfa will depend on conditions. I usually start in the middle setting and adjust from there. One thing I've noticed in alfalfa is the cutterbar will knock out as many or more leaves than the impellers do. And some varieties are much more prone to losing leaves this way than others. Weather conditions make a big difference as well. You can set an impeller machine to do absolutely nothing to alfalfa, or you can "meal" it. It's all in the setting. Mike

Randal There is not correct setting without knowing the volume of crop going through the machine.

How I set them is to set it deliberately too aggressive. Mow 20-30 feet. Go back and look at the hay. Pick up a section of hay with your fingers like a pitch fork. So you looking at more than an individual stem. When it is set too aggressive the hay will have a fuzzy or stringy look to it. Set the board up one hole at a time. Test mow 20-30 feet. When the fuzzy look just goes away you have it set as aggressive as you can with out damaging the hay.

The first time or two it may take you 10-15 minutes to set it. After that maybe 3-5 minutes. You learn to judge the hay volume and tenderness of the hay.

Randal give me call and I can walk you through it.

Rod find me where it says to not use a JD 920 on more than a 90 HP tractor in the JD 920 operators manual ????

A JD 920 impeller machine NEEDS more than 90 HP in tall thick hay. I have seen them work a JD 4430 in thick hay.

I don't know about the 920 specifically but the 1460/70 were VERY CLEARLY stated that you do not apply more than 90 horse. They also need more than 90 to keep speed in heavy crop... but I can assure you that when they get it, bad things happen. The dog clutch will blow apart... the bar coupling will explode, etc etc. They are power limited for design purposes, not because they couldn't use more.

Rod