[chllngr528]

Which is better a "A" pump or "AA" and why?

 

[bob_hefley]

I will be corrected if I am incorrect, but I believe that the difference between an A or AA pump is just the mounting pattern on the pump.

 

[chllngr528]

I think a "A" pump is a larger body pump. My real question is is it stronger then a "AA" pump?

 

[Hydriv]

Both of you are right.

The AA pump is the baby of the pump world, meant to go in small spaces but tiny pumps mean small output capacities compared to the next pump size up, which is the A pump. Originally, Colt and Case went with the A pump but as the tractor morphed from the old 100 Series into the 200/400 Series, space became a problem and the A pump gave way to the smaller AA. If you can find the space for the A pump, it would be my choice because it will handle much higher pressures and that's why it was selected for the loader and loader/hoe tractors.

If you make this a dedicated Puller, then you could switch to a foot control for your right foot and get rid of the travel lever and the mid-lift lever along with the mid-lift cylinder.

 

[chllngr528]

Lol so you already new what I was thinking Tom. I already have the pump mount. I bought it off ebay last year for $5 from Joes. I really don't know what I am doing with it yet. For now I'm going to continue to experiment and see where it goes. But since I already have the mount and my old pump seems to be a leaking a little I might as well upgrade before I button her back up.

 

[chllngr528]

Now onto the next question........what "A" pump should I get? Should I just get the one posted in the FAQ or should I get one that's a little bigger

 

[Hydriv]

Now onto the next question........what "A" pump should I get? Should I just get the one posted in the FAQ or should I get one that's a little bigger

Here's your dilemma.

If you go to a larger pump, then you will increase you maximum ground speed by whatever percentage the increase is.

EXAMPLE. Let's say you have a 10 GPM pump in there now. So....you change it to a 12 GPM pump. That's a 20 percent increase in pump output and that translates to a 20 percent greater ground speed.

Sounds good, right?

But then you run head on into the "there's no such thing as a free lunch" issue. It already took X amount of HP to run the stock pump at 3600 RPM so that you could achieve the 10 GPM that the stock pump was rated to produce. If you don't increase your engine HP, then the larger pump may pull the RPM down and your output flow will actually fall below what you had before. You would be worse off. I am not a Pulling game expert but as I see it, high ground speed can only be achieved in the super modified classes where they run custom built Kohler engines capable of revving to six grand or more and producing more than 50 HP. You are in the stock class and that's a good place to stay because it is relatively cheap. You need to focus on traction, weight distribution and maintaining a slow, steady unstoppable pull. If the Cub's are limited to a 3600 RPM engine, then I don't see them getting much more ground speed than you.

I'd rather see you jack the relief to 3000 PSI and try both motors to see which one pulls the best. If you can find a good hydraulics guy that knows these motors, then he might be able to tighten up one of your motors internally so that you can get higher torque and a bit more ground speed.

 

[chllngr528]

Actually that don't sound good at all when you put it in those terms. I'm not looking for more ground speed. I'm looking for less.

As I have it set up now I'm at 3000psi for my relief valve already and don't want to go much further. It no longer pops the relief valve when I'm pulling. It runs out of engine. In other words I pull until she stalls. I said this before on here I think, it feels like I'm trying to pull the sled in too high of a gear. Now the only way to get max power to the wheels is to have the TC lever almost all the way up. I know it sounds like I should be able just back off the TC lever to pull at a slower speed but when I do that she will stop pulling. My next step was to put a 400 series motor in it for more gear reduction but I never got around to it. The pull is this weekend and I just finished up the engine. I have to finish painting it this week and drop the engine in. I have a grainger over here somewhere and I was going to slap and new pump in and call it good.

I also already replace the ball joint connectors for the linkage so I know my linkage is super tight. (See I already new what you were thinking)

 

[Hydriv]

The way to give your existing engine greater ability is to go in the opposite direction to more ground speed.

Putting on the 400 motor means a larger internal displacement, slower turning motor that will deliver higher torque to the wheels. If that doesn't do it for you, then go with a smaller internal displacement pump. You will go slower, yet again but the engine will not bog down as badly.

So let's look at it this way...

Suppose for a second that you have a .62 cubic inch AA pump and it has a theoretical GPM of (.62 X 3600 = 2232 divided by 231 = 9.66 GPM @ 0 PSI)

If you want to slow the tractor's speed down by 30 percent, then you need a pump that puts out (9.66 X 70% = 6.76 GPM)

A pump in the vicinity of .42 cubic inches would give you (.42 X 3600 RPM =1512 divided by 231 = 6.55 GPM @ 0 PSI)

As an example, this pump has the sort of specs you would be looking for. http://www.grainger.com/Grainger/HALDEX ... Pid=search

It will put out as much as 4000 PSI for you. I can't tell you what the drive motor will handle or even the trans-axle gears but those are big gears and the axles are pretty robust too. Pulling is always about pushing what you have until something breaks and then you make that weak link stronger and push again in the hopes that you can win without breaking something. You could check with Surplus Center's site to see if they have a pump like that for less money.