ATF Fluid instead of Hydraulic Fluid

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Hey Guys - And Bob!

Got a question. I build 5hp racing engines for kart racing. We use a hydraulic dyno for testing the engines. When I built my dyno I talked to the guys at Haldex Barnes and they recommended I use ISO-68 AW20 for the fluid. So far it has worked great for me.

Now, talking to other engine builders they are telling me they are using ATF fluid (Mercron and Dexron) in the same application. The reason they give is the fluid is already thin so no need to wait for the fluid to come up to temp to get accurate readings. They also claim it is better on the pump for wear. When I ask them why they use it, the standard answer is always "because that's what xxxxx is using". No one knows the real reason behind using it, only because that's what they have heard of others are using.

What is your opinion on using ATF in hydraulic applications.

The service is generally 1500-2500 psi, 90-120 degrees F, no oil cooler or heater.

Thanks,
Jamie Webb
First Coast High Performance
 
Jamie,

I design, build, and rebuild hydraulic equipment - with the primary application of woodsplitters. Most of my hydraulics run at 1500 psi max. and provide 45 tons of splitting force from 36" to 42" cylinder with 3" to 5" bores.

Both Prince Valves and Haldex Barnes recommended to me that I use Dexron III ATF or equivalent. Both companies have stated that synthetic ATF's may also be used as well. I use primarily the larger single-stage HB gear pumps, but the smaller two-stage pumps run very well on ATF.

I have used both hydraulic oil (ISO 32/46) and ATF and I prefer ATF by a wide margin.
The ATF comes up to temp sooner, is essentially a 0W20, and has all kinds of neat additives. I have since replaced all hydraulic oils in my machines with Dexron III ATF.

Schaeffer's has a superb ATF, #204S.
 
BTW,

I use no oil cooler either. Our sumps are built into the welded I-beams and compartmentalized.
The mass of the steel compartment dissipates heat very effectively.

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Big advantage is in the VI. A good Dexron will have 190 VI, and a Hydraulic around 100, so the Dexron works like an ISO 32 at 40C and an ISO 68 or better at 100 C. Better pumping at low temps, less seal and hose breaking. Better pressures in hot weather with less leakage.
 
Wildman, thanks for the info.

Bob. Nah, we haven't moved on yet. Still right down the road from you. I will call you in a week or two for some more Citrol (Awsome stuff).

Ok, back to the real question. Ok, so after reading the info here and talking to the guys at Barnes Pumps I think I will go with the ATF. Now, how do I decide if I want to use Dexron, Mercron, or F?? Any opinions welcome!

Talk to ya soon Bob!

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MolaKule,
Good info you gave. I also use a Barnes pump. Mine is a single stage, 1.21cubic inch, pressure balanced gear pump. Sounds like our pumps are similar.

Now, how do I decide what a "good" dexron III is? I guess from the info you gave and wildman look for the one with the highest VI?

Guess I need to do some info searching!
 
I just looked up the 204s to see what the VI index is. 196, not bad, honestly never looked at that before.

One thing I thought was interesting is how the atf sticks to parts. I think I showed that to you before where we took equal parts of fluid in two jars, shook and set them down and most will drain off very quickly where the 204s just stays on there. This was after setting them both down exactly the same time from being shaken up with one hand. This picture was taken at 15 secs from time it was set down.

 -


Thats one reason why some of the PSD transmission builders like this stuff so well.
 
Jamie,

I'd still go with the wide VI Schaeffer's #204S that Bob showed.

Most of the H-B pumps I use are 2.33 cui or larger with greater than 20GPM flow rates, set to 1,200 to 1,500 psi by the Prince valve, which I calibrate myself, and driven by 16-25 HP Kohler's (My favorite engine). I do supply systems with Brigg's if the customer wants, but standard engine is Kohler single's (K341's) and twin's for most applications.
 
Thanks guys. Bob, shoot me a price on 5 gallons of the 204s at [email protected]

I'll be ready in about a week or so to get some. Let me know the price and delivery time. Then I'll give you a call when I'm ready. I'll get the Citrol at the same time.

GREAT board. Where else can you get off the wall application answers??!!?? Thanks!
 
Molakule....can i pick your brain a bit about log splitter hydraulics?

i'm in the process of (re)builing one now. someone used a 5" x 24" cylinder with a little 5 gpm pump on a 5hp engine. needless to say, it's extremely slow and not enough power.

i intend to use a 12hp engine, a 16 gpm two stage pump and a 12-15 gallon tank on this machine. (along with some newer control valves)

what tonage can i be looking at with this set up?

i appreciate any advice!!
 
quote:

i intend to use a 12hp engine, a 16 gpm two stage pump and a 12-15 gallon tank on this machine. (along with some newer control valves)

what tonage can i be looking at with this set up?

Much depends on the pressure the system can develop at a specified RPM. Check those pump specs and then we can give you a more accurate force result.

Good choice on the tank capacity, the more fluid the better, since the oil life will be extended.

I would recommend as a minimum 3/4" pipes and hoses to and from cyclinder. Unfortunately, some older cylinders have 1/2" fittings so you may have to use a reduction adapter to make your connections there.

Northern Tool has an excellent detented control valve just for wood splitters that has 3/4" in out orifices. It has adjustable fluid pressure settings as well.

For the tank to the pump, I would use at least a 1" hydraulic hose, or as large as pump permits. For added efficiency, make sure your pump is the below tank.

I would plumb a filter in-line (return line to tank after the valve) as well with a Baldwin HF922 and filter adapter with a 35 psi relief valve (you only filter at idle anyway). This reduces heat and contaminants in your oil as well.

The theoretical maximum pressure that you can develop from your current set-up (using your current numbers) is:

1,028 psi.

Force = Area X Pressure = 20,157 Lbs.f = approx. 10 tons.

With a Barnes two-stage pump, the system efficiencies are a bit more than the hydraulic equation results.

BTW, later this summer we're introducing a hydraulic fluid for wood splitters and similar hydraulic applications.

I use as a minumum 16 Hp engines and Barnes single-stage pumps for high flow with a pressure limit setting of 1,500 psi.

BTW, since you will be replumbing, place guages around the system so you know what your system conditions are. As a minimum, place a pressure guage on the inlet side of the cylinder.

[ April 07, 2005, 01:52 PM: Message edited by: MolaKule ]
 
thanks, Molakule. i printed out your suggestions for reference.

i have a 27hp wisconsin engine, but no one wants to take the time to adapt that to the splitter, so we're using a 12.5hp tecumseh. Hopefully it's strong enough.

10 tons?? hmmm...how do they come up with 30 tons using the same size ram with a smaller engine?

i appreciate your help with this!!
 
quote:

12hp engine, a 16 gpm two stage pump and a 12-15 gallon

quote:

10 tons?? hmmm...how do they come up with 30 tons using the same size ram with a smaller engine?

Who are they and what initial data (assumptions)are they using? How much poressure are they saying is being develpoed by the pump at a specified engine RPM? Force = Pressure X Area. That's the real physics of the problem. Since your area is constant, the only variable's are flow and pressure. I calculated the above based on your flow rate and the amount of pressure the pump could develop at the Hp stated.

I would have to seriously doubt Tecumseh's Hp specs. At what rpm is this engine developing 12.5 Hp. Take that number and multiply by 0.75.
 
ok...i saw this one at northern tool. the specs are listed below the page it's on. they use an 8 horse engine, same size ram as i have, and mention a "heavy duty 2 stage pump".

i apologize for my ignorance about hydraulics, but i was lead to believe using the same items i would achieve the same force.


http://www.northerntool.com/
ITEM NUMBER 11501

i concur with you about the engine hp rating and i assume it would be at WOT to get 12.5hp, but surely it would have to be suffice...no?

if i were to use a higher GPM pump, would that benifit me? does it have to be dual stage or single?
 
HP - flow - pressure are inter-related. Pressure and cylinder area, as reported by several above, create force.

rule of thumb ... 1 gpm, 1500 psi, 1 hp.

pressure in PSI, flow in gpm, "normal efficiency"
HP=pressure*flow/1500

Theoretical, 100% efficient
HP=pressure*flow/1714

you can get, with commercially available products, 10,000 psi at 0.18 gpm with a 1.5hp motor ... the cylinder will move really slowly. You can get 100 psi at 18 gpm with that same motor ... 100 times the speed, 1/100 the force. Thus, the "2 stage" pumps commonly used which in the industrial market, we call "high-low" systems. There are "better" options, but tehy cost more money.
 
quote:

i concur with you about the engine hp rating and i assume it would be at WOT to get 12.5hp, but surely it would have to be suffice...no?

if i were to use a higher GPM pump, would that benifit me? does it have to be dual stage or single?

In the two-stage pump or "high-low" one stage brings the pressure to a certain level while the other increases it still further. The 2-stage system is supposed to allow a good flow with specified pressure while requiring a lower Hp engine.

As per the equation from GB, the more GPM or flow for the same area requires more Hp.

Take for instance my hydraulic wood splitters using a single stage Barnes pump:

1. Flow - 18-22 GPM
2. Pressure - 1,500 psi max
3. Engine - 16 Hp.
4. Cylinder - 5" bore, 32" stroke.

It moves slower than would a 2-stage pump and 6-12 Hp engine but the force is tremendous. The cylinder is from a Catepillar Bull Dozer.

So if you want more flow or pressure, you have to have more Hp driving the pump. For most people using a 24" stroke cylinder with a 3" bore, the Barnes 2-stage pump with a 6-12 Hp engine should suffice.

I change my hydraulic fluid twice a year since I split wood year round. I use our own ISO 46/68 Anti-wear hydraulic fluid.
 
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