BX25 Transmission filter relocation and COOLER

[Tachdriver]

As you may remember, we last talked about my Engine Oil Filter relocation project and during that discussion a gentleman, Volfandt suggested I ramp it up a notch and launch a project to relocate the hydrostatic trans filter and install a cooler with thermostatic bypass while at it.....http://www.tractorbynet.com/forums/kubota-owning-operating/209562-bx-25-remote-oil-filter.html

....well I accepted that challenge. The parts you see are the following

1. Steel tubing
2. Dakota oil psi gauge 0-150
3. Dakota trans temperature gauge
4. 1993-95 Mazda Rx7 stock oil cooler
5. 7" Amazon.com cooler fan
6. Simple on/off switch
7. Summit Oil filter relocation kit
8. Various fittings


The Rx7 oil cooler is top notch design. 10 row plate all aluminum oil cooler with a 140F oil bypass. After 140F is reached - ALL oil is passed thru the cooler. Up until then it is primarily bypassed.

The flow is as follows - Out of the Transmission, past a oil pressure tap, into the oil filter, out of the filter and into the cooler inlet, out of the cooler and past a temperature tap and back to the transmission. All openings are at least 1/2" or bigger.

I am running out of usable room so the gauges had to be mounted in CF pods and installed on the hood. Had some reservations over this but once installed I like it. I can see the readings clearly. The raising of the hood is unimpeded.

Mounting the cooler took more thought. Again the BX25 is strapped for room and I already have a lot of mods installed. I ended up making a bracket and drilled/taped the bottom side of the ROPS for the bracket. Originally was going to clamp it but ran out of room, I was surprised to see the ROPs thickness to be almost 1/4" in this area. Threads are 3/8" -24 fine thread. The oil filter pedestal is mounted on the fender. Getting to the fuel cap is not a problem.

I put a switch on the fan so that I have control of the temperature, especially in colder weather.

Now for the test. The pump outlet pressure runs 110 psig to the oil filter. This was confirmed by the gentleman who looked it up for me in his manual (thanks). Everything is rated to sustain this pressure. Rx7 oil pressure is greater than that at times, so the cooler is good. I had a large pile of dirt from a recent excavation that I needed to move and spread around. The outside temperature was close to 90F that day. I worked on that pile for a good three hours until it was gone with the FEL. My oil return temperature never got over 130F and that was with the fan off. Turn the fan on and it drops 5 to 10f quickly. It takes a long time to get to 130F and once there lingers +/- several degrees. Even though the cooler is still in bypass at that temperature I know a flow is passing thru it also because it gets warm. You can see the oil psi on the left gauge and the temp on the right one.

In summary I believe this mod will extend the life of my Transmission, the hydraulic lines and cylinder seals. I have read of BX hyd oil temps getting over 200f in others machines. It was satisfying to think this out and make up all the plates and adapters. I had to weld fittings on the stock Rx7 oil coolers to accept 1/2" npt.

I believe I am about done modifying my machine for now, at least the major stuff. I worked on my road today with the Ratchet Rake and enjoyed every minute of it. I had bought a canopy for it off of ebay and put it on when working in the hot sun, another good piece to have on these machines.


So, thanks for the challenge Volfandt....and in the words of one of my good friends - "Is that all you got" ! Hope you like it

Later

 

[corey9212]

That's sweet I love the gauges, with that cooler in place will it act as insurance if your HST fan breaks or would you still need the fan?

 

[Tachdriver]

Now there are experts on this far better than me, but I would bet I could take that fan off and throw it out and still not go over 150F. But who knows for sure :laughing:


later

 

[corey9212]

Now there are experts on this far better than me, but I would bet I could take that fan off and throw it out and still not go over 150F. But who knows for sure :laughing:

later

If that's true then you should apply for kubotas development team, maybe stupid little mistakes like the fan placement won't happen anymore. Keep up the good work.

 

[OrangeRidge]

This is THE MOST interesting thread I've seen in a loooong time !
My BX trans temp hits 180f in conventional form. I'm impressed
at your temperatures without the fan activated . Just shows
how little heat can be dissipated by the cheap factory fan blowing
on a big lump. If left to idle for 5 mins after a 3 acre cut , the temp
drops 15f on the trans . This is ofcourse what you should do to
let the engine temp reduce too ( hood open ) !

 

[Volfandt]

Absolutely outstanding
Sir, I stand impressed
I really like the idea of a cooling fan for the heat exchanger as it adds even more cooling efficency. Perhaps an automatic heat sensing switch, such as whats found on our small car engines, could be added for automatic fan control. That said, I think the manual switch is fine. I'm a gauge watcher by nature so manually throwing a switch when needed is fine for me.
Your use of the limited space and mounting points availability on our BX's is also impressive.
As you pointed out, there just ain't no room on them

One favor, if you will, could you add a pic or two of your adapter mounting down at the original filter mounting as well as your hose routing from said?

Bravo to you Tachdriver. May you reap a just reward for your fabrication skills
Dave

P.S. I'll be studying this for a while as I think this to be a worth while project for my own BX23

 

[Tachdriver]

Here is the adapter on the transmission, the lines, the cooler preparation, the hood wiring inside, the cooler fitting welding and cooler hydrotest etc.

The adapter on the transmission is the Summit racing kit adapter that I spoke of in the last thread.

later

 

[Tachdriver]

No problem - here it is again

Summit Racing SUM-G4985-1 - Summit Racing® Oil Filter Relocation Kits - Overview - SummitRacing.com

You will NOT find a better kit for the price they are asking. All of the parts are high quality.

:thumbsup:

Here is the 1/2" tubing

Allstar Performance ALL22120-8 - Allstar Performance Steel Tubing - Overview - SummitRacing.com

Later

 

[OrangeRidge]

Thanks for all the photos :thumbsup:

 

[sw03]

so how many degrees is it cooler for all the work?

 

[Tachdriver]

Before I installed anything, and the original filter was in the stock position, I ran the tractor for several hours and turned it off and could not keep my hand on the Transmission housing. I did not have a temperature reference for that but it was darn hot. Now I can lay my hand on it a lot longer without removing it.

That is a good question though. If anyone is running a temperature on the case then I like to hear it. I read somewhere it is 200F. Does the Japanese Kubota have a trans temperature reading ? If anyone can tell me FOR SURE if there is a plug on the case that I can insert a temperature sender then I'll hook on up

LAter

 

[Tachdriver]

Calling on CTJAY - is there a plug in a circuit on the BX transmission that I can pull and insert a temperature gauge sender - 1/8" npt ?

later

 

[rdsaustintx]

HANDS DOWN the coolest mod I have seen in seven years of reading this board.

Just plain outstanding.

 

[OrangeRidge]

This is as hot as it's got . Top reading is sun shining on the
units in-built sensor . 95f in the shade that day . 2 hrs cutting.
Trans quickly reduces to 170f at idle ( within 10 mins of PTO off ).

 

[jakell2010]

I don't want to step on any toes,,,,but

Sometimes there are reasons why fluids run at the temperatures you experience, for example,,,maybe To give you an idea that your overworking a specific machine. Or that the fluid " was designed" to operate OPTIMALLY at a temperature which you would consider hot.

I've found that there are people who are much smarter than me who design these machines that we buy, and something's ( especially with things where I don't know ALL THE REASONS of why they are what they are) things MAY NOT be an improvement to the original design

 

[ModMech]

I would not care to comment specifically on UTF, but for ATF 140*F is "too cold" and 170*F is "optimum", with 190*+F being too hot.

UTF (Universal Tractor Fluid) is a lot thicker than ATF and closer to engine oil in viscosity and lubrication requirements. 230*F is widley regarded as approaching dangerous temperature for engine oil, I would ASSume that similar temperature limits exist for UTF.

I do recall my uncle's old Farmall would heat up the hydraulics hot enough that you DID NOT want to touch it and that was just from cultivating.

 

[Volfandt]

Modtech, you just may have commented/answered the UTF question in your post inadvertantly

You indicate that UTF is closer to engine oil in various categories and to expand on that, some L&G HST manufacturers (Sunstrand in particular) changed from ATF to engine oil in the early days and all if not most now require engine oil for cooling, lubrication and operation of modern L&G HST's.

In looking at the oil cooler Tachdriver used. He used an engine oil cooler w/a thermostaticlly controlled bypass. Basically the oil bypasses the heat exchanger until it meets/exceeds 140f, then it reroutes the hot oil through the heat exchanger to cool it off.
I think we can surmise that cold oil seems to work better and when testing out HST's one of the major recommendations is to see how it operates once its warmed up, as it's more prone to fail once the fluid has heated up to operating temps.
Cooler oil also does a better job of dissapating heat of the component it's circulating through.

IMHO, the HST cooling system of our BX's is good -to- adequet when considering all the extremes it's designed to operate in. I'm sure the engineers determined that as long as we run the proper oil (UDT/SUDT/SUDT2) which is designed to operate in these extremes, that the tractors will operate and not destroy themselves in these extremes. But thats not to say that cooling that HST fluid down when finish mowing 2 or more acres on a 90degree day is a bad thing either

SCUTs are the only modern utility tractors that utilize a driveshaft driven fan to cool the HST and it's oil down. All the others use a heat exchanger, normally mounted in front of the engine radiator so it can utilize the same fan to draw cooling air through both. Some of these "others" have similar power and are the same size as the SCUTs.
It's also of note that JD's newest SCUT has done away w/the HST cooling fan setup and gone to an external heat exchanger.

It would be nice to have an engineer contribute and let us know what the "ideal" HST oil temp should be. I could be wrong but I'd guess it's alot south of the temps OrangeRidge posted and more inline w/what Tachdrivers HST heat exchanger provides.

Dave

 

[ModMech]

Dave,

Sounds like the same thinking Allison was using 20 years ago when they advised we transition to a C4 rated engine oil in our ATs - to lubriace better and cool more effectively.

 

[dodge man]

Very nice mod, and very well executed. Is this mod necessary? Probably not. Is this mod make the tractor better and make the life of the HST better? I'd say yes!

 

[jcy110]

Looks great. I see in your photos that you have the older model stabilizer lock (bungee cord....LOL), I have the newer model. Its one of the 1" nylon straps with a hook on each end and a cinch buckle that holds the tension until you release it. Flip the feet upward, attach hooks and pull to tighten. they never move at all until you loosen them manually. Nothing worse than parking the BX somewhere and returning to see the stabilizers laying out like a dead spider against something you don't want scratched!