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NAA pto

K

Keith True

Well-known Member
I just got out an NAA that I want to sell.I noticed it has a little hydraulic pump that runs off the rear of the main pump,and the tach drive running off the back of that.I see a little hydraulic line that runs back to where the PTO lever would normally be.I'm assuming this is a live PTO setup.Is this a plus? Minus? Or,no big feature on this particular tractor.I had kind of forgotten the previous owner had bought this tractor to restore because it had live power.If it is a worthwhile extra I thought I might blast and paint the tractor before I sell it.
 
(quoted from post at 18:16:36 12/15/18) I just got out an NAA that I want to sell.I noticed it has a little hydraulic pump that runs off the rear of the main pump,and the tach drive running off the back of that.I see a little hydraulic line that runs back to where the PTO lever would normally be.I'm assuming this is a live PTO setup.Is this a plus? Minus? Or,no big feature on this particular tractor.I had kind of forgotten the previous owner had bought this tractor to restore because it had live power.If it is a worthwhile extra I thought I might blast and paint the tractor before I sell it.
Click to expand...

If it is complete and works a plus and should add a bit to the value of the machine. Most are incomplete and/or do not work.

TOH
 
As TOH said, if complete and working, a nice option.
I took one out of a NAA that was complete except for that little
pony pump. Obviously it wouldn't work without it. I ran some
tests using compressed air and could see that it engaged and
disengaged so I advertised the whole set up on an eBay auction.
I think it brought about $40 including the side cover and handle.
It was an incomplete unit, but that's the thing about auctions.
If the right buyers were there, it may have brought more.

mvphoto28058.jpg
 
(quoted from post at 19:40:09 12/15/18) As TOH said, if complete and working, a nice option.
I took one out of a NAA that was complete except for that little
pony pump. Obviously it wouldn't work without it. I ran some
tests using compressed air and could see that it engaged and
disengaged so I advertised the whole set up on an eBay auction.
I think it brought about $40 including the side cover and handle.
It was an incomplete unit, but that's the thing about auctions.
If the right buyers were there, it may have brought more.

mvphoto28058.jpg
Click to expand...

At $40 bucks that was a bargain. The pony pump produced a tiny flow and it would not be hard to split that amount off the main pump output. In fact a while back I was going to help a fellow do exactly that but he managed to get his pony pump working. I think the Ford engineers over thought this one.

TOH
 
Installation requires a rear split, not too bad of a job if you have the proper facilities, tools, and, maybe, a helper.

I certainly would not take the time to install one without first verifying that it was properly functional and rebuilding anything that could be rebuilt.

Dean
 
So this really isn't truly a live PTO.A live PTO would involve a shaft coming off the rear of the engine that would run all the time.This looks more like a rear end disconnect of some sort,maybe the pinion?? I have a Howard manual one on an 8N that I think does the same thing,just manually,not with a hydraulic clutch pack.This tractor also has a steering wheel with planetaries in it,like a Model T Ford.It takes more turns,but it steers with one finger.It also has a cable operated Sherman trans in it.
 
(quoted from post at 11:57:49 12/16/18) So this really isn't truly a live PTO.A live PTO would involve a shaft coming off the rear of the engine that would run all the time.This looks more like a rear end disconnect of some sort,maybe the pinion?? I have a Howard manual one on an 8N that I think does the same thing,just manually,not with a hydraulic clutch pack.This tractor also has a steering wheel with planetaries in it,like a Model T Ford.It takes more turns,but it steers with one finger.It also has a cable operated Sherman trans in it.
Click to expand...

No - assuming we are talking about the proper gadget this is a true LPTO.

The Howard is a reduction gearbox placed behinf the main transmission that reduces ground speed without reducing PTO speed. It does not do anything as far as live PTO goes.

The NAA widget is a hydraulic clutch in the exact same location as the Howard but it does nothing wrt ground speed. What it does is disconnect the the drive wheels without disconnecting the PTO. That is the definition of live PTO.

In a hundred/thousand series te LPTOt operation was done by a mechanical two stage clutch positioned ahead of the transmission. With the NAA it was done with the hydraulicly actuated clutch behind the transmssion.

The disconnect happens at a different point in the drive line but the the operational effect is the same - live PTO.

TOH
 
I'm sorry,I got the 8N thing wrong.It doesn't have a Howard unit in it,it has a Hernandon-Rotory traction disconnect.It was used to run a Howard Rotovator that actually bolted to the rear of the tractor.When you don't look at the line of tractors for a few years you tend to get them mixed up.I do understand what you mean about the live PTO on the NAA.I just still have it in my head that if you stomp on the clutch pedal and the PTO quits,it ain't live.This just has the same result by acting like it has a second stage in the clutch further down the stream.
 
I agree that it is not a "real" LPTO.
It is simply a driveline clutch.
Live PTO is done by means of a double clutch and dual input shafts into the transmission.
See photo.
It WOULD be a good add on to a tractor with transmission pto in that it allows you to stop forward motion while allowing the pto to continue to turn.
But I suspect it would be neither as intuitive nor handy as the "real" McCoy.
Allis Chalmers did a similar thing on the WDs with their foot+hand clutch setup.
cvphoto6131.png
 
Just a technicality here...
If you want a tractor that the clutch does not affect the pto at all when you stomp on the clutch pedal you have to get one with Independant PTO.
I suspect you know that tho.
 
(quoted from post at 14:30:16 12/16/18) [b:55745047ab]I agree that it is not a "real" LPTO.
It is simply a driveline clutch.[/b:55745047ab]
Live PTO is done by means of a double clutch and dual input shafts into the transmission.
See photo.
It WOULD be a good add on to a tractor with transmission pto in that it allows you to stop forward motion while allowing the pto to continue to turn.
But I suspect it would be neither as intuitive nor handy as the "real" McCoy.
Allis Chalmers did a similar thing on the WDs with their foot+hand clutch setup.
<img src="https://www.yesterdaystractors.com/cvphotos/cvphoto6131.png">
Click to expand...

[b:55745047ab]Question:[/b:55745047ab] What is the function of the first stage of a two stage tractor clutch?

[b:55745047ab]Answer:[/b:55745047ab] - It is a drive line clutch

This is a silly semantic argument. Ford and Allis called it a live PTO as did other manufacturers who used this scheme. The means of actuation is different but it still lets you stop the tractor without stopping the PTO. That is the essence of what is meant by LPTO.

TOH
 
What are you calling the first stage?
On a dual clutch tractor the first stage
to engage is the pto.
Scenerio: With that add on unit you could
disengage both clutches - one with your
hand and one with your foot, put both the
transmission and pto into gear, let your
foot out to engage the pto, then engage
the drive with your hand to start moving
forward.
Works good but having both functions on
the pedal is Much more user friendly.
The user friendly part is similar to my
main complaint about Independent pto.
Scenerio 2: You're bush hogging along and
the mower gets caught up on a big rock.
Mower is banging away and tires are
starting to spin. You have to do a bit of
rewiring of your brain to remember to
simultaneously shut down one function with
your foot and one with your hand.
Of course in that scenerio on the NAA you
just stomp on the pedal and shut
everything down - just like a dual clutch
tractor. But generally you Would have to
do some 'rewiring' to remember which
clutch to use at what time to make
effective use of it.
Call the thing what you will. I don't
mind.
I have said here before I think they were
kind of a gizmo and inferior to 'real'
Lpto - partly because they so rarely still
work and partly because they are less user
friendly than a dual clutch live pto.
In their defence though, if you had one
that worked good it Would be better to
have it than not. I also think the idea of
adding a proportioning valve and run it
off the main pump is better than what Ford
did.
By the way, just an fyi here.
Ford ran a pump off a pump in later years
too. On the 3 cyl 4000s they had a little
hyd pump that was run off the main hyd
pump. It only put out about 200 psi and
was only used to operate the pto.
 

i've got a hand clutch on my WD. u say it's not as user-friendly as a two stage foot clutch, but i have no problem sparing a hand to work it. i like it a lot.
 
(quoted from post at 17:23:14 12/16/18) What are you calling the first stage?
On a dual clutch tractor the first stage
to engage is the pto.
Scenerio: With that add on unit you could
disengage both clutches - one with your
hand and one with your foot, put both the
transmission and pto into gear, let your
foot out to engage the pto, then engage
the drive with your hand to start moving
forward.
Works good but having both functions on
the pedal is Much more user friendly.
The user friendly part is similar to my
main complaint about Independent pto.
Scenerio 2: You're bush hogging along and
the mower gets caught up on a big rock.
Mower is banging away and tires are
starting to spin. You have to do a bit of
rewiring of your brain to remember to
simultaneously shut down one function with
your foot and one with your hand.
Of course in that scenerio on the NAA you
just stomp on the pedal and shut
everything down - just like a dual clutch
tractor. But generally you Would have to
do some 'rewiring' to remember which
clutch to use at what time to make
effective use of it.
Call the thing what you will. I don't
mind.
I have said here before I think they were
kind of a gizmo and inferior to 'real'
Lpto - partly because they so rarely still
work and partly because they are less user
friendly than a dual clutch live pto.
In their defence though, if you had one
that worked good it Would be better to
have it than not. I also think the idea of
adding a proportioning valve and run it
off the main pump is better than what Ford
did.
By the way, just an fyi here.
Ford ran a pump off a pump in later years
too. On the 3 cyl 4000s they had a little
hyd pump that was run off the main hyd
pump. It only put out about 200 psi and
was only used to operate the pto.
Click to expand...

Semantic arguments just to be contrary are not helpful. First stage to disengage is the drive line clutch. That is the same as first stage to engage is the PTO clutch. Which one is the first stage to act depends on direction of operation which should be obvious. DOH!

Tandem and triple pumps are common and they work great. They are made with this exact situation in mind and that would have been a reasonable approach. I am sure Vickers would have had no problem providing a tandem pump to replace the stock pump. Instead Ford opted to hang a separate pump on the tachometer drive that was never designed with that in mind. IMO a clumsy afterthought more worthy of my shop than a company with the resources Ford had available.

In reality a second pump was unnecessary. A really simple way to power the LPTO would have been to replace the block off plate on the hydraulic top cover with a flow divider that diverted a portion of the main pump flow to the LPTO accumulator. They already had that designed into the top cover circuitry for use with the optional Selectrol valves which they were also manufacturing. The flow needed to charge the LPTO accumulator is so tiny the 3pt operation would have been unaffected. The flow divider could have been manufactured as a simple bolt on monoblock that stacked under the regular plate or one of the Selectrol valves. That engineering was already done and no need for a second pump or suction line.

TOH
 
Instead Ford opted to hang a separate pump on the tachometer drive that was never designed with that in mind. IMO a clumsy afterthought more worthy of my shop than a company with the resources Ford had available.

In reality a second pump was unnecessary. A really simple way to power the LPTO would have been to replace the block off plate on the hydraulic top cover with a flow divider that diverted a portion of the main pump flow to the LPTO accumulator. They already had that designed into the top cover circuitry for use with the optional Selectrol valves which they were also manufacturing. The flow needed to charge the LPTO accumulator is so tiny the 3pt operation would have been unaffected. The flow divider could have been manufactured as a simple bolt on monoblock that stacked under the regular plate or one of the Selectrol valves. That engineering was already done and no need for a second pump or suction line.

TOH
Click to expand...
This points to an all-too-common problem still evident today. Companies do not communicate effectively internally. Solutions are developed in vacuums and not communicated outside their business units, or even within. This leads to constant reinvention of the wheel and less than optimal solutions overall. Had they shared information the end result could have been a more simple, less expensive solution that solved the problem at hand. Just my $.02. :)
 
(quoted from post at 20:15:15 12/16/18)
Instead Ford opted to hang a separate pump on the tachometer drive that was never designed with that in mind. IMO a clumsy afterthought more worthy of my shop than a company with the resources Ford had available.

In reality a second pump was unnecessary. A really simple way to power the LPTO would have been to replace the block off plate on the hydraulic top cover with a flow divider that diverted a portion of the main pump flow to the LPTO accumulator. They already had that designed into the top cover circuitry for use with the optional Selectrol valves which they were also manufacturing. The flow needed to charge the LPTO accumulator is so tiny the 3pt operation would have been unaffected. The flow divider could have been manufactured as a simple bolt on monoblock that stacked under the regular plate or one of the Selectrol valves. That engineering was already done and no need for a second pump or suction line.

TOH
Click to expand...
This points to an all-too-common problem still evident today. Companies do not communicate effectively internally. Solutions are developed in vacuums and not communicated outside their business units, or even within. This leads to constant reinvention of the wheel and less than optimal solutions overall. Had they shared information the end result could have been a more simple, less expensive solution that solved the problem at hand. Just my $.02. :)
Click to expand...

Maybe - or maybe it was really low priority and they gave it to a junior engineer in the PTO design group for on the job training and he wanted to do his own thing. To be clear on that last comment - I am not a chauvinist just pretty darn sure it was a "he" and not a "she". ;-)

TOH
 
[i:654c4848f0]"Semantic arguments just to be contrary
are not helpful. First stage to disengage
is the drive line clutch. That is the same
as first stage to engage is the PTO
clutch. Which one is the first stage to
act depends on direction of operation
which should be obvious. DOH"[/i:654c4848f0]

Not sure why you're going off with the
semantics and contrariness stuff Toh.
I well understand semantics - probably
better than you but don't know why they're
mattering to you here.
You wish to call that added on clutch
thing live pto. I said before what you
call it is ok with me.
I'm not going to call it live pto. I might
just call it a doohicky driveline clutch
that failed early and often.
I hope that's ok.
 
(quoted from post at 17:55:15 12/16/18)
(quoted from post at 20:15:15 12/16/18)
Instead Ford opted to hang a separate pump on the tachometer drive that was never designed with that in mind. IMO a clumsy afterthought more worthy of my shop than a company with the resources Ford had available.

In reality a second pump was unnecessary. A really simple way to power the LPTO would have been to replace the block off plate on the hydraulic top cover with a flow divider that diverted a portion of the main pump flow to the LPTO accumulator. They already had that designed into the top cover circuitry for use with the optional Selectrol valves which they were also manufacturing. The flow needed to charge the LPTO accumulator is so tiny the 3pt operation would have been unaffected. The flow divider could have been manufactured as a simple bolt on monoblock that stacked under the regular plate or one of the Selectrol valves. That engineering was already done and no need for a second pump or suction line.

TOH
Click to expand...
This points to an all-too-common problem still evident today. Companies do not communicate effectively internally. Solutions are developed in vacuums and not communicated outside their business units, or even within. This leads to constant reinvention of the wheel and less than optimal solutions overall. Had they shared information the end result could have been a more simple, less expensive solution that solved the problem at hand. Just my $.02. :)
Click to expand...

Maybe - or maybe it was really low priority and they gave it to a junior engineer in the PTO design group for on the job training and he wanted to do his own thing. To be clear on that last comment - I am not a chauvinist just pretty darn sure it was a "he" and not a "she". ;-)

TOH
Click to expand...
Quite possibly. We see that a lot, too: A new kid is told to "Go do X" with little instruction, or guidance. Later on people are often surprised with the less than optimal results....

I'm pretty sure it was a "he", too. :)
 
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