When roto-tilling how much engine RPM drop?

   / When roto-tilling how much engine RPM drop? #1  

North Dakota

Silver Member
Joined
Nov 28, 2007
Messages
125
Location
Mandan ND
Tractor
'84 Ford 1710
I have a ford 1710 with a 60 inch KK II tiller attachment the tractor has a 3 cyl diesel with a 24 hp PTO. Tiller manual says not to lug the tractor when tilling. KK web site says 25 to 40 HP recommended PTO HP.

OK onto my question. I set the RPM to 2400 which is the 540 PTO speed. Put the tiller in the ground and start tilling. The RPM will drop some 100 - 200 rpms and to get it back to 540 PTO speed I give the tractor a little more throttle. To me this would seem normal for a tractor doing work.

When is to much RPM drop a problem? What is considered lugging? To me a lugged engine would blow black smoke from the exhaust and have quit a bit of RPM loss.
 
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   / When roto-tilling how much engine RPM drop? #2  
Sounds like you're doing fine. Depending on soil conditions you'll experience some RPM drop when you fully engage the tiller in the soil. You can feel the lugging factor, it's like trying to take too steep a hill in hi gear in your truck. It doesn't sound like you are having a problem, keep on grinding up that dirt.

John
 
   / When roto-tilling how much engine RPM drop? #3  
North Dakota:

"To me a lugged engine would blow black smoke from the exhaust and have quit a bit of RPM loss." I think you answered your own question. My "29" is comparable to your 1710 as is my tiller to yours. If I sense the tractor starting to strain (usually on the first pass on new sod) I increase throttle and/or raise the tiller slightly. I believe that the "specs" on the KKII tiller are very conservative as to PTO HP recommendations. Jay :)
 
   / When roto-tilling how much engine RPM drop? #4  
I beleive some get "working" an engine and "lugging" an engine. A working engine will show black smoke , but holds RPM's near where you start. A lugging engine will drop many RPM's. Am I wrong in this accessment?
 
   / When roto-tilling how much engine RPM drop? #5  
A 'lugging" engine will not respond to increase of the throttle as if it can not cope with excess demand put on it. Reducing the throttle bring a lugging engine closer to normal condition, the same can also be archived by gearing down a lugged engine. As far as tilling RPM, I personally do not look at engine rpm, based on the soil type I set the throttle as low as I can to achieve the consistency I need. For my type of soil, I run my ford 1700 @ about 1300to 1600 RPM at whatever pto RPM it happens to be, that's enough to till my soil to powder consistency and the engine is just purring along. Saying that, the tractor is designed to operate the implement @ 540 rpm. For 1700 that means 2550 engine Rpm. Engine should be able to do that for hours on end if in good mechanical shape without any damage.

JC,
 
   / When roto-tilling how much engine RPM drop?
  • Thread Starter
#6  
Thanks for the advice guys. I think everything is just fine then.

I Had to laugh at myself the other day. When I bought my tractor I put in the lowest gear it just crept along slower then a walk. I thought when would I ever use this gear? I found out it works real good for tilling unbroken ground. :D
 
   / When roto-tilling how much engine RPM drop? #7  
The comment about running lower than 540 PTO rpm's makes me think of a related question - How often do you guys run attachments at 540 PTO rpm? Mowers, tillers, chippers, whatever. Seems to me the tractor is working pretty hard at high rpms, and using a lot of fuel. In many cases, I can run lower speed and the tractor seems to be a lot happier and still has power to do the job. Tractors don't last forever, so I try not to stress my engine for no reason. Running at 540 PTO rpm seems like its hard on the engine, and might shorten the life of the tractor if you do it for hours on end.

However, I understand how the governer on a diesel works - it adds fuel to keep the rpm at whatever you set it for (not really the same as a throttle on a gas engine). So in theory, the diesel with a fixed load uses almost the same amount of fuel at any rpm. But in practice, it sure sounds like its working hard at high rpms.

Can anyone shed light on this?
 
   / When roto-tilling how much engine RPM drop?
  • Thread Starter
#8  
kbuegel said:
The comment about running lower than 540 PTO rpm's makes me think of a related question - How often do you guys run attachments at 540 PTO rpm? Mowers, tillers, chippers, whatever. Seems to me the tractor is working pretty hard at high rpms, and using a lot of fuel. In many cases, I can run lower speed and the tractor seems to be a lot happier and still has power to do the job. Tractors don't last forever, so I try not to stress my engine for no reason. Running at 540 PTO rpm seems like its hard on the engine, and might shorten the life of the tractor if you do it for hours on end.

However, I understand how the governer on a diesel works - it adds fuel to keep the rpm at whatever you set it for (not really the same as a throttle on a gas engine). So in theory, the diesel with a fixed load uses almost the same amount of fuel at any rpm. But in practice, it sure sounds like its working hard at high rpms.

Can anyone shed light on this?

My KK tiller manual says that the tiller was design to operate properly at 540 RPM only and warns of going above that. The only thing I could think that might happen with running at lower speeds then 540 RPM would be oil distrubition in the gear boxes on top and on the side of the machine might not splash around enough to get all the gears slopped with gear lube. It seems unlikely that that would be the case but at load under low rpms maybe damage could happen as the top gear in the side gear case of my tiller is quite a distance above the static oil level.
 
   / When roto-tilling how much engine RPM drop? #9  
My Befco 66" tiller does not load down my tractor at all when all the down. I generally run in 2nd gear low range at about 2300 - 2400 rpms. The rpm's required to get 540 PTO speed is 2700. The fuel consumption between 2700 and 2400 is a lot and just seems to be less stress on the machine.
 
   / When roto-tilling how much engine RPM drop? #10  
I have a 1910 and use a 60" Howard rototiller. It will drop a few hundred RPM as well when the tiller is digging deep. I wouldn't worry.
 
 
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