Attacking that power problem CT225

[bbse]

Two things

1. I may have a weak relief valve but I figured out how to get up that hill in mid range. I hit it at a angle, not quite 45 degrees, probably more like 30 or so. I am talking about side to side now. I guess that takes some of the up angle out as I can go right up it like that. Luckily, with loaded tires it is still very stable.

2. I hauled it down to west TN to work on some property down there. It is very flat. I can see where someone not dealing with steep hills would not notice the relief valve issue. I have a few tractor length banks but I went right up them loaded with no problem.

Haven't heard back from the service manager, doubt if I will. I will have to start calling I guess. Anyways, I think this thread is about done. As soon as I have new info I will start a new thread.

 

[dfkrug]

From my research, the CT235 does have a different relief valve than the CT225/230.

How did you find that out? What is the spec for the RVs on the CT235 HST?

A dealer could look up the part #s for 2 different M27 tractors, but he
would not have the pressure setting unless he looked it up in a service
manual. If someone had a Bobcat parts book, it may cover all 3 models in
the same book, like my Kioti CK25/30 parts book does for 2 models. It could
tell you if the part numbers ar different, but not the specs.

If indeed the HST RVs are set higher for the CT235, I have no doubt you
could put one in other M27s. Getting one just for Forward would be enough.
I would do it.

 

[bbse]

Someone emailed me a parts breakdown list for the 225/230 vs the 235. The part numbers were different but your right, pressures were not listed so I do not know those numbers.

 

[SPYDERLK]

From my research, the CT235 does have a different relief valve than the CT225/230.

How did you find that out? What is the spec for the RVs on the CT235 HST?

Probably followed up on post #65 ....
larry

 

[MtnViewRanch]

Just thought that I would post some more info for you guys to compare. I have a Mahindra 3215HST. Supposed to have 32hp, dealer says that they usually dyno out at 34hp. :thumbsup: My tractor has all tires filled, weight with loader and box blade is right around 5000lbs.

I put my bucket into a large pile of dirt so that the tractor would not move forward.

I first checked to see if the tires would spin at 1500rpm. Low range spun no problem. Mid range would not spin the tires, just loaded the motor. High range was the same, just loaded the motor.

Then I raised the rpm up to 2000. Low range spun the tires, mid range spun the tires, high range would not spin the tires, just loaded the motor.

The last rpm range that I checked was 2500. I very seldom run the tractor at this rpm, but went ahead and checked it. All the same results as at 2000rpm.

I have looked at my service manual, and the relief valve for my tractor is supposed to be set at 4974psi at 50*C. Based on how my 3215HST performs and the what seems like low RV setting is, my guess is that these smaller tractors have a lower RV setting. My tractor performs very well in all ranges. Now for the most part I only use high range for transport, but it has no problem going up hill without any noticeable slowing.

Just thought that I would share some info from another brand so that you would have some more references to compare too.

 

[dfkrug]

I have looked at my service manual, and the relief valve for my tractor is supposed to be set at 4974psi at 50*C. Based on how my 3215HST performs and the what seems like low RV setting is, my guess is that these smaller tractors have a lower RV setting.

That is an interesting test, Brian. Mahindra no doubt uses lower gearing.

In the HST issue with the DaeDong tractors, one could argue that the
designers chose either a too-low RV pressure, OR too-tall gearing. Or both.
The best comparison is two tractors where the only difference was the
engine....can both spin tires in LOW?

 

[MESSMAKER]

That is an interesting test, Brian. Mahindra no doubt uses lower gearing.

In the HST issue with the DaeDong tractors, one could argue that the
designers chose either a too-low RV pressure, OR too-tall gearing. Or both.
The best comparison is two tractors where the only difference was the
engine....can both spin tires in LOW?

It has a 13mph top speed in high. hard to believe it is too high geared.

 

[MtnViewRanch]

It has a 13mph top speed in high. hard to believe it is too high geared.

The 3215HST has a top speed of 11.3mph with 27x8.5-15 / 15x19.5 industrial tires. I think that the BCs have the same size tires. Can someone confirm tire sizes? That would put the BCs at a 15% higher gearing.

More things to ponder.

It looks like the rears are the same and the fronts are on 14" rims 27x8.5-14.

 

[bbse]

The forward speed for the Kioti CK27/30/35 HST with AG's is 13.07. I think it should be the same as a CT225/230/235. The size listed is (Ind1 4WD- Rear 15x19.5). Now the other day I seem to remember seeing that with R4's were running 11 MPH instead of 13 MPH. I remember thinking that I thought Ag's should have been slower as I thought they were shorter....but since I can't find it I may just have a faulty memory.

Link to Kioti

KIOTI - run ahead of the pack!

Link to CK27 HST PDF

http://www.kiotitractor.com/attach_files/Products/CK Series Catalog 05-2009(3).pdf

 

[dfkrug]

It has a 13mph top speed in high. hard to believe it is too high geared.

The total gear ratio in LOW range will determine if the engine can deliver
enough force to the tires in order to spin them. If the HST is constrained
to a pressure of 5000psi max, then the gear ratio needs to be lower in
order to spin the tires in a hi traction situation. The 3215 does what I
would expect a properly designed HST tractor would do.

My Bobcat had the 11.2-24 R1 tires, and it would have higher traction, but
taller gearing (diameter) vs my CK30 that has 15-19.5 R4s. As I said
earlier, both can be put into situations where they can not spin tires in LOW.
IMO, that is a design mistake in either RV pressure or LOW range gear ratio
(or both).

 

[dfkrug]

I posted the wrong HST RV pressure for the CK25/30. (I think the 5000psi
number was from the B21....oops.)

From page 4-37 of the CK25/30 service manual, it is:
280 kgf/cm2, which is 3980psi

For the CT225/CT230, KRAZK reports that the HST RV is also 280,
while the CT235 is 300 kgf/cm2, or 4260psi. CANADA_CT230
reports the CT225/230 to be 4061psi, while the CT235 is
4351psi. I imagine there are two different parts of the
service manual where these specs are reported?

I am still waiting for a report on the CK35 RV spec. I will post
all these in my CK-CT comparison thread.

Initially, it seems that buying the CT235 RV and putting it
into lower-powered M27s is a good thing to try. I wonder
what the M24s use (DK35/CT335).....

 

[bbse]

Spoke with the service manager today at Bobcat Nashville. He tells me that he is working with a engineer at Doosan to find a way to up the relief valve. The CT235 does have a higher pressure valve but it also has a different body size and thread. He is having them build one for him....I get to be the guinea pig on this one.

 

[lilranch2001]

congratulations (maybe) good luck! :thumbsup:

 

[tinman955]

I hope that is the solution, you might go from no spin, to just stall the engine. I feel the engines lack power, gearing not correct and relief settings to low.

How to fix im not sure but I do know the only way to fix them or improve them is to atleast try, im glad yr heading in the right direction.

 

[SPYDERLK]

I hope that is the solution, you might go from no spin, to just stall the engine. I feel the engines lack power, gearing not correct and relief settings to low.

How to fix im not sure but I do know the only way to fix them or improve them is to atleast try, im glad yr heading in the right direction.

2-300 extra psi would let him climb and restart on that hill he cant restart on.
Stalling wont be an issue at partial pedal because hes only pumping a little fluid. The key is that he wont be wasting it out the RV.
larry

 

[bbse]

2-300 extra psi would let him climb and restart on that hill he cant restart on.
Stalling wont be an issue at partial pedal because hes only pumping a little fluid. The key is that he wont be wasting it out the RV.
larry

This is what I believe also. I took the loader off yesterday to do some mowing. Up until now I have been leaving it on as I needed it to often to be taking it on and off. I can actually climb and mow the shallower sections of the back hills without popping the relief valve. But that is a short section. As soon as it steepens slightly I lose the valve but I can still keep the rpm's. I don't know how much more pressure it will take but I am going to stay after them until I can spin those tires. I figure that ought to be enough.

As to power, I hit 72 hours and it is starting to get a little more pep. I expect it is almost to full power now, it is a lot better than it was new. I had the same experience on my 3054 after I rebuilt the engine. It takes a while to break in and get all the power out of it.

 

[dfkrug]

Spoke with the service manager today at Bobcat Nashville. He tells me that he is working with a engineer at Doosan to find a way to up the relief valve. The CT235 does have a higher pressure valve but it also has a different body size and thread. He is having them build one for him....I get to be the guinea pig on this one.

That's interesting. I would love to hear the results.

Can we assume that he checked the RV pressure and got something near
the 3980psi spec? And that he has seen the two different RVs side-by-side
to state they are different body sizes?

I did not do the HST pressure test on any of my units....my guage only
goes to 4000psi. I need to get another gauge first. The test port is
on top of the gearcase below the front lip of the seat.

 

[tinman955]

Is the HST pressure adjustable like the loader valve is?

 

[dfkrug]

Well, for those interested, I removed the forward RV from my HST. The
adjuster screw in it is fixed in place with a tiny weld. It IS adjustable if
you grind the weld off, then reweld to secure it. I have posted a new
thread:

http://www.tractorbynet.com/forums/...increase-hydrostatic-transmission-relief.html

You can see from pix I posted that the RV itself has no threads on it, but
if the one for the CT235 or CK35 has a larger diameter, it will not fit. I
doubt the part would cost much, or one could just buy an RV for the
CT225/CT230 and modify IT, rather than the original one. Gotta get the
guage first.

 

[socketcap]

BBSE I have a 2008 ct230 with the exact same problem over here in NH, did you ever discover the source of your diesel engine running out of rpm and torque and eventually stalling?