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Hancock county, IL | I have a friend trying to chop silage with a New Holland 770 chopper with older New Holland 2 row 30 inch head. He is chopping 30 inch corn that has decent height(length). The head knives are cutting the plants off fine and the gathering chains seem to be pulling the crop up fine. The problem is that the head will plug right at the rolls that pull the corn into the machine. It seems that the corn is turning from vertical to horizontal as it should to enter the machine but after this phase it plugs. He has tried changing the head speed from the medium to lower speed sprocket and vise versa and it has not helped. He has noticed if he only chops the outer row it seems to work as it should. Can anyone give us any ideas of things to check or try.
Thanks for any help. |
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Wisconsin | I'd lower the push over bar some so the bottom of the stalk hit's the roll's faster and first. It would say in the book to do that for taller corn and for short stuff like popcorn you raise the pushover bar just below the tassel hope it as just that simple to get it to feed and most times it can be. |
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Faunsdale, AL | Never seen a NewHolland cutter, but some general things to try...........
Make sure the down pressure springs are installed and not broken etc. Also check that the roller that has teeth on it has sharp teeth. Not rounded edges, square edged, like they were sheared out on a metal shear is great. Might have to spend some time with a side grinder and square them up if they're rounded.
Then (carefully) raise the front upper roller with a bar, block it up with a 4x4 or something similar and feel the surface of the rear rollers just in front of the knife head/shear bar. There should be a smooth path with no jutting edges on the lower side of the throat. Usually there is a smooth roller with a scraper on it to keep it clean. Sometimes the scraper needs adjusting downn tigher to the roller so it scrapes clean and does not stick up to catch the crop that's being shoved across it.
Lastly, make sure the knives are sharp and the shear bar is set correctly. If the chopper has long thick knives, the bevel behind the edge is very important. Fox recommended a 7/8" bevel on theirs and it was important to have it. Thin knives' bevel isn't as important and you can't change it anyway. The bevel is important because the feed rolls are pushing the crop in at a constant rate as the knives are passing through it. A properly beveled knife cuts and then the bevel allows the crop to be pushed on in even as the knife is moving across the cut surface of the mat of stalks. A short bevel momentarily stops the progress of the stalks and can break the grip of the feed rolls on the stalks and they "spin out".
Symptoms of problems in the throat and feed rolls is that the stalks are feeding fine and then suddenly they fall flat on the header and the feed rolls just spin on the top of the ones remaining under the front roller. |
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| Iirc, 2 rows of good corn is a lot for that chopper/size of feed rolls. I could never get it to work very good anyway. Seemed to get as much done driving faster and chopping one row vs. slower and two rows in good corn. If it did feed in, something else on the chooper would bother because it was just to much material for that chopper. Check to make sure the springs that hold pressure to keep the feed rolls together are not broken. Often they look ok until you look way at the bottom where the bolt holds them and adjusts the tension. If broken, the rolls will just lift up under a load and not pull like they should. Also make sure both rolls are driving like they should, that one is not just driving the other making it look like both are turning until you get a load in them. You can also change the speed of the feed rolls to see if that helps but it might affect your length of cut. |
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| I'm not familiar with that chopper.... but the symptoms are in line with a Deere that doesn't have all of it's feedrolls turning. Check that there's no broken shear bolts, chains or shafts. Deere also love hex shafts to drive the rolls and they will round off... and basically do what you describe under ~heavier~ loads but mabey work OK under light load.
Rod |
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Effingham, IL | If I remember correctly I used feed-roll springs off of an 890. I can't remember if I had to cut them to length. Too many years and brain cells ago! Craig
Edit: Also make sure the smooth roll and scraper are adjusted properly. The smooth roll scraper can cause a major feeding problem!
Edited by CW IL 8/28/2012 23:08
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south central WI | We have had the feedrolls shear of from the hub. The feedroll will spn and look ok. Once a load is put on, it will just sit there and not pull crop in. Had that happen on our smooth feedroll this summer on a CIH FHX300, only 2-3 yrs old. |
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NCOhio | We had the same problem. I think the teeth on the upper feed drum were worn and bent back and wouldn't grab the stalks very well. You might try welding a new edge on them. |
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Western Oregon | I've had that problem with a 718 and 890. Everyone else has pretty much given the best ideas.
1. Adjust the stalk bumper so the corn is feeding in at the correct angle.
2. Make sure the feedroll tension is cranked down tight.
3. Feedroll speed a little faster than the head is delivering the corn
4. Make sure all the rolls are driving. The drive sprockets can slip on the splined shaft and you don't always see it. One of the rolls has a shaft all the way through it which I think has a keyway. So the shaft can be turning and the rolls not.
5. Smooth roll turning and the scraper adjusted up tight.
I think it should handle two rows.
We ran a 718 on a Minneapolis-Moline G1355 in 30 ton corn with a two row head. Both the old style and new style heads and it only bunched when there was a problem with the feed rolls. You didn't want to shut it down before the spout cleared and you didn't want to start up too fast but it worked fine otherwise. I thought the 770 was bigger than a 718.
Good luck! |
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New Holland 770 silage chopper issue
