When roto-tilling how much engine RPM drop?

[randy41]

I have a 1710 and pull a 48" tiller. it's a ford 105A tiller. I recently installed new blades and i notice the engine changes pitch slightly when the tiller is engaged. after the blades get worn it doesn't do this but it also doesn't till as well. so i would say the rpm drop is not significant.

 

[JC-jetro]

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.

I tend to disagree with that statement. If you look at the level point (the hole that shows you had added adequate oil) in a gear driven KK tiller you'll notice the oil totally covers most of the lower gear , middle idler gear and half of the top gear... even @ 100 rpm of the tiller the gear will see adequate lubrication the same as set of bevel gears in the gear box above. What matters is quality of soil in general and the degree of tilling one needs. I don't drive at the speed limit because the sign says 65 MPH, I drive some where lower than 65 where I feel safe considering all the road conditions,..... kind of same logic with the PTO speed

JC,

 

[akazad1]

what is the reason behind high rpm drop in puddling application(pulverization of soil ) often used in wet land areas in southern Andhra pradesh ,INDIA

 

[Reg]

IMO "Lugging" is when the revs drop so low that a stall SEEMS imminent.
With a rototiller hitting a hard spot, or unusually large rock, it can actually stall the tractor.
Generally not good, sometimes disastrous.
SOME diesels can suffer all sorts of internal damage when stalled under heavy load and then additionally shock loaded - meaning a sudden additional load, e.g. a rock jam in the tiller.

So, if it is dropping WAY down, say below 2,000 on full throttle, decrease ground speed or decrease depth - almost that simple.

I think the slip clutch won't ALWAYS protect against stalling.
Well, if you have it so loose that it smokes like a burning off Harley rake, maybe,
but you don't want to run like that for very long.

 

[Reg]

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.

Pretty sure mine says at or below 540, i.e. no lower limit.
Trust me on this one; Oil climb isn't very dependent on speed, within some reasonable range, i.e. the oil will get everywhere it needs to at speeds as low as 50 RPM, probably lower.

Try it sometime.
Run the tiller high off the ground with the engine at idle for just a second or so.
Stop it, lower the 3 point, get out your tools and take the side cover off.
Betcha a week's pay there is still oil sliding down the insides of the cases (-:

 

[Mechanos]

Another consideration would be the direction of rotation of the tines. Some tillers rotate with the directions of travel, some rotate against the direction of travel and some are capable of operating in both modes.

 

[Dingeryote]

I run either a Woods 72 or a Kuhn 72 on our 1920.

Ground is either sandy loam or heavy black swamp muck, depending on the field.
2-300 rpm drop is normal when the tiller bites.

For what we do, running the PTO @ 540 and keeping forward travel good and slow for aeration, and busting up bits of organic matter into a fine and fluffy layer. Bogging happens down around 1500rpm in the clay/Marl around a couple ponds, and you WILL know "Bogging", when you hear it and feel the little Ford complaining.

Running the thing at 540 under a light to moderate load, doesn't wear the mill any more, than running it at a lower RPM.
Those nice Engineer folks at Shibura, optimized the torque curve, lubrication, cooling, and everything else for running at that speed under a load.

Some will argue that due to reduced lubrication and coolant flow, longer time with rings under pressure, and less flywheel effect, operating under a moderate load at lower rpms, MIGHT actually cause increased wear. I dunno. I ain't an engineer, and have heard from a couple slide rule types, that such things have been addressed on modern tractors, especially Deere, considering thier "E" PTO settings.

Tillers with gears get sufficient lube at any speed, if the gear oil isn't worn into watery consistency. Tine shaft gear, gets dunked and carries it to the idle gear, and then to the drive gear. Flinging 90-120 takes some doing, the stuff is tenacious, and it ain't happening at the speed the gears are spinning.

Set the thing for 540, and pick a gear that allows the Tiller to remain at a constant depth. If it's rising out of the cut or leaving clods, drop a gear.
If she wants to crawl while nibbling, let it crawl.

 

[oldballs]

Although new at tilling with a tractor, I found that the HST transmission allows me to immediately slow the ground speed down to allow the tiller to "catch up" when it bogs down in a heavier wet area....and then the engine smooths right out again.

 

[Reg]

Although new at tilling with a tractor, I found that the HST transmission allows me to immediately slow the ground speed down to allow the tiller to "catch up" when it bogs down in a heavier wet area....and then the engine smooths right out again.

Try it with a geared tractor - - SO much better ain't it ?

 

[RedNeckRacin]

I run either a Woods 72 or a Kuhn 72 on our 1920.

Some will argue that due to reduced lubrication and coolant flow, longer time with rings under pressure, and less flywheel effect, operating under a moderate load at lower rpms, MIGHT actually cause increased wear. I dunno. I ain't an engineer, and have heard from a couple slide rule types, that such things have been addressed on modern tractors, especially Deere, considering thier "E" PTO settings.

The "E" setting on a Deere runs the implement at 540 rpm though. Just in case anyone wasn't sure of that. It lets the motor turn at around 1700 and the pto to turn at the full 540. I really dont see any harm at running slower than 540, except that the implement was designed to work at that speed. I can think of a few conditions where you might want to slow a little or speed up a little.

To exaggerate a little; why in the world would you want to run an implement at idle instead of working it near its rated speed unless you like spending alot more time in the seat? Maybe it makes more sense with a tiller to slow it down incase you find a larger rock, but isn't that what shear bolts and correctly adjusted clutches are designed for?

As for the OP, a few hundred rpm drop just means the tractor is taking on load. If it continues to drop, thats lugging it down. The tractor should have enough power to maintain the speed on the tach and to get the full pto hp, you gotta run at the rated tach speed. Otherwise, your not putting all the hp to the dirt.