Max pto speed on MD

sflem849 · May 8, 2011

The MD is totally healed (with the exception of a dead battery, after the first $1000 you would think I would just spend the next $100 :lol: ) It doesn't seem like it runs fast enough on high idle and never has.
My friends have the checker that you can put on the PTO and check it's speed, but I am not sure how fast it is supposed to go. I know on more modern tractors 540 PTO speed is not at WOT. It is usually about 90% of WOT. [b:8da7b9ec0a]The big question, how fast should the PTO be spinning at WOT?[/b:8da7b9ec0a]

SouthernFarmall · May 8, 2011

The PTO is supposed to run at 540 at full throttle. The speed will vary according to engine speed (in the neighborhood of about 1/3 the speed of the engine). So, if you are running at 900 rpm, you will have approximately 300 rpm at the power take off.
SF

pete 23 · May 8, 2011

It should run about 595 rpm so anywhere from about 590 to 600 is about right.

sflem849 · May 8, 2011

When I checked it today it was around 450. That would mean I am at about 1350 by that math. Makes sense since max road speed is about 16 mph.

Harold H · May 8, 2011

It should be at about 540 at maximum rated engine rpm.

Harold H

pete 23 · May 8, 2011

To clarify a little better. Wide open throttle is not rated engine speed. We have about an 8 to 10 percent govenor on most ag engines, therefore you start out with higher rpm so at a full load you will be running rated engine speed which is 1450 on the MD and 535 on the pto. Been that way since the beginning and still is.

sflem849 · May 8, 2011

(quoted from post at 17:52:35 05/08/11) To clarify a little better. Wide open throttle is not rated engine speed. We have about an 8 to 10 percent govenor on most ag engines, therefore you start out with higher rpm so at a full load you will be running rated engine speed which is 1450 on the MD and 535 on the pto. Been that way since the beginning and still is.

So it should be 588.5 at WOT?

So I was pretty much dead on when I said most modern tractors look to have PTO speed at about 90% of max rpms. I guess I am smarter than I thought. :lol:

pete 23 · May 8, 2011

Yup, got that settled, now the problem is that a lot of mfg's including IH strayed away from rated engine speeds meeting std pto speeds. One example is an 806 Diesel with a rated engine speed of 2400 rpm, max high idle speed 2640 and std pto speed of 1000 rpm or 540 rpm at 2100 engine rpm. You had to set a dyno to read at 1146 or 616 ( if memory serves me correctly) to check horse power at rated engine rpm. Led to a lot of incorrect dyno readings and lots of complaints about pto horsepower. They switched back to rated and std on the 50 series. I have no idea what the new ones are. Not my problem anymore.

Bob M · May 8, 2011

Yup - 580 - 590 RPM at WOT and no load. But when operated with the PTO loaded and delivering rated power (38 HP) you should see 540 RPM.

If you're seeing only 450 RPM wide open and no load, the governor (inside the injection pump) or linkage between the throttle handle and the injection pump needs attention.

sflem849 · May 8, 2011

Yeah, I there is A TON of slop in the throttle. I am not going to fix the slop right now, but I am going to at least get the engine running at full speed. Might help me out on the 13' disc :wink:

I found the spot in the book. It reads

This attachment shaft is a standard SAE 1 3/8" inch spline and revolves at 540 rpm at the rated load engine speed of 1450 rpm...

So with math we take 1450/1610=.9006 So 10% is very accurate. That would make the WOT PTO speed 594.2 rpms. Sorry, I like to over think things.

mkirsch · May 9, 2011

If you don't fix the slop, then you're never going to get full throttle.

sflem849 · May 9, 2011

(quoted from post at 05:42:24 05/09/11) If you don't fix the slop, then you're never going to get full throttle.

I know, but you can't do it all at once.

M Diesel · May 9, 2011

(quoted from post at 06:53:48 05/09/11)

(quoted from post at 05:42:24 05/09/11) If you don't fix the slop, then you're never going to get full throttle.

Click to expand...

I know, but you can't do it all at once.

The main thing on an MD is that ball joint in the throttle linkage where the linkage turns down hill over the side of the engine. It never gets greased and wears badly, eventually forming a tongue and groove kind of thing. It creates artificial stops and won't let the travel go to both min and max anymore, just barely reaching both ends. Otherwise there are no stops except those inside the pump.

Standard on an IH ag pump is 11% regulation. Setting high idle is very easy, done by a screw under the pump oil filler cap. It's the one where the screw head goes to the right and the head bumps against the case. Screw it in a little to up the RPM.

ScottyHOMeY · May 9, 2011

General practice on the letter series is that the Max RPM shown on the serial plate is "no load," which is 110% of the rated speed under load. Whichever way works for you, multipy htat number by 8/9ths, divide by 11 and multiply back by ten . . . the number you arrive at is where you would check your PTO speed.

I've been known to go the other way around.

In the tight quarters at the front of the motor on my BN, it's hard to get a good reliable point to get a piece of reflective tape for the laser tach to tick and then see it.

I set the governor and idle on it measuring the speed of the PTO shaft. 595 or so at the shaft made for 1540 RPM, 200 or a whisker more on the shaft makes for 525 on the motor.

sflem849 · May 10, 2011

The main thing on an MD is that ball joint in the throttle linkage where the linkage turns down hill over the side of the engine. It never gets greased and wears badly, eventually forming a tongue and groove kind of thing. It creates artificial stops and won't let the travel go to both min and max anymore, just barely reaching both ends. Otherwise there are no stops except those inside the pump.

Standard on an IH ag pump is 11% regulation. Setting high idle is very easy, done by a screw under the pump oil filler cap. It's the one where the screw head goes to the right and the head bumps against the case. Screw it in a little to up the RPM.

Mine doesn't have a way to grease that ball if you did want to. You could put some on your finger and try to pack it in. You could also shoot a little oil in there from a can. It would be better than nothing.

I'd like to see mkirsh whip me out one of the ball and socket contraptions and the bolt/rod thing that the bell crank pivots on. Fixing the slop is that easy...

M Diesel · May 10, 2011

(quoted from post at 04:39:34 05/10/11)

Mine doesn't have a way to grease that ball if you did want to. You could put some on your finger and try to pack it in. You could also shoot a little oil in there from a can. It would be better than nothing.

I'd like to see mkirsh whip me out one of the ball and socket contraptions and the bolt/rod thing that the bell crank pivots on. Fixing the slop is that easy...

Click to expand...

You're right, there is no fitting. I'm not sure what the official lube technique is supposed to be.

McMaster-Carr still sells that type of ball joint. Mine needs it terribly bad, but I haven't replaced it yet. Not sure which one it takes and I'm a long ways away from the tractor. Since they are a bit pricey ya don't want to reorder to get the right one. Twice now we have pulled the linkage apart while working on other stuff and didn't get it back exactly right. Both times it took an hour to figure out what was wrong. DUH! Also didn't realize until the second time that the ball is shot. Oh well... better late than never! At least the new power steering setup works fabulous.

sflem849 · May 10, 2011

(quoted from post at 10:36:43 05/10/11)

(quoted from post at 04:39:34 05/10/11)

Mine doesn't have a way to grease that ball if you did want to. You could put some on your finger and try to pack it in. You could also shoot a little oil in there from a can. It would be better than nothing.

I'd like to see mkirsh whip me out one of the ball and socket contraptions and the bolt/rod thing that the bell crank pivots on. Fixing the slop is that easy...

Click to expand...

You're right, there is no fitting. I'm not sure what the official lube technique is supposed to be.

McMaster-Carr still sells that type of ball joint. Mine needs it terribly bad, but I haven't replaced it yet. Not sure which one it takes and I'm a long ways away from the tractor. Since they are a bit pricey ya don't want to reorder to get the right one. Twice now we have pulled the linkage apart while working on other stuff and didn't get it back exactly right. Both times it took an hour to figure out what was wrong. DUH! Also didn't realize until the second time that the ball is shot. Oh well... better late than never! At least the new power steering setup works fabulous.

Click to expand...

Yeah, mine is a PITA to get back on as well. The PS TG is in the way. The PO ground down the key and that helps a bit. I put that thing on backwards one time, too. I figured it out pretty quick though. For some reason the screw wasn't hitting the stop...duh...

My dad's work orders from McMaster Carr almost daily. I will have to have him order me the ball setup. I plan on taking the tractor to his house and fixing all the sloppy joints. He lives about 3 blocks from his work and they have a mill and lathe that we can use. A lot better than working on the tractor at my house that is 30 min from the mill.

I'm not really sure how I am going to fix the sloppy rods. It is easy to fix the sloppy holes with bushings, but I haven't found a strong solution to fixing the rods.

M Diesel · May 11, 2011

(quoted from post at 20:33:51 05/10/11)

I'm not really sure how I am going to fix the sloppy rods. It is easy to fix the sloppy holes with bushings, but I haven't found a strong solution to fixing the rods.

Did the backwards thing too :lol: It isn't real obvious at first until the mechanism interferes.

Thinking about it, it might be from Graingers but most likely McMaster-Carr. One of the two. They have an odd name I can't recall right now so the search isn't straight forward. If you find the right one please post it. The bolt/nut end is easy because it just has to fit that hole, it's the threaded end I'm unsure of.

In the past, the rod wear would be a torch issue, as in build it up and grind back to what you need. I always liked acetylene for that. Takes a little patience, but goes quicker than you think.

sflem849 · May 11, 2011

My friend really likes to practice TIG welding. That is what we used to build up the shifter on my H. The only problem with that is he grinds the crap out of everything in the name of "surface prep." Something about TIG isn't as tolerant of impurities and dirt.

McMasters search is terrible to use in the first place. Then if you don't know the exact name of what you want it is even worse. One time I called the phone number...I won't do that again. They were worse off than I was!

M Diesel · May 11, 2011

Yeah TIG has it's limits. A torch let me float out stuff and control heat better, especially when slobbering in some filler on an odd shape.

Found them under ball joint linkages.
http://www.mcmaster.com/#ball-joints/=c9ihg9

The heavy duty one seems appropriate but probably any are better than what is there now.

Max pto speed on MD

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