3rd Function on Mahindra 4350

[irsmun]

There are steel lines from the pump that connect to 1/2 hoses then to the loader valve. I am assuming hoses and the steel lines are the same size but I don't really know the ID of the hoses. Its then 1/2 hoses from the loader valve to the same size steel lines to the rear and the power beyond. 3/8 hoses to the FEL and 1/4 to the cylinders.

 

[J_J]

If 3/8 in hose are going to the FEL, then the flow is limited by the flow coming from the FEL.

So if the FEL is using 3/8 in hose then what is the problem with using DO3 3/8 in ports?

Have you had any problems with heat so far?

This should have been an easy workup for this project.

 

[irsmun]

It should have been easy but you are having to deal with my ignorance also.

Because the PB hose is 1/2 and, if I understand this right, the subplate for the 3rd function will be routed right in the middle of this hose. Yes, 3/8 to the FEL. But now you have reduced the once 1/2 PB hose to the rear to a 3/8 via the P and T port. Right?

Its not the connection to the loader I am addressing. Its the flow to the 3pt via the PB line. That will have a 3/8 in the middle unless I get a subplate with 1/2 P and T ports. It looks like to me I am squeezing my PB line flow down to 3/8 from 1/2 and the back to 1/2 after the subplate.

Please correct me if I am not seeing this right.

 

[J_J]

The limiting flow in your hyd flow path has been answered, and by adding a 3/8 in DO3 subplate you are not really losing much.

The 3pt will still get the same flow as before.

 

[irsmun]

So you are saying that my flow rate will stay the same throughout the system but it will simply speed up and increase in pressure in the 3/8 section of the subplate. So my guess is that as long as the subplate can handle this extra pressure and dissipate the heat properly then I shouldn't notice any changes in performance?

JJ, you are one patient man. and just so you know I have learned a lot from this thread.

 

[J_J]

There are two ways to check your flow.

A good flow meter.

A 5 gal bucket and time the flow with engine at max rpm and using which ever hose you want.

One gal of flow in 6 seconds would be 10 GPM.

 

[irsmun]

I think I will be happy if someone who has installed one of the kits chimes in as to their subplate size vs their input/output hose size. I don't need to blaze this trail. Its already been done. I just need verification before I do it to MY tractor. When watching the install videos on youtube, I don't remember them mentioning hose sizes.

You didn't answer my question. When a larger pipe flows into a smaller pipe then either the pressure has to increase or the flow rate. The difference in 1/2 verses 3/8 is significant in a diameter. Add to that the pressures we are talking about here and something has to happen. Remember, I didn't just want to talk about this so someone could tell me what to do. I wanted to learn through the process and hopefully help other hydro-ignorant newbies. So I guess I am trying to get an explanation of why this reduction doesn't affect the circuit.

JJ, I take it you are older than me. You are welcome to hit me with your hat. :confused3:

 

[J_J]

The pump is still trying to pump the flow dictated by the engine rpm, and when you reduce the flow by decreasing the port size, the flow will decrease and the flow velocity will increase, therefore increasing heat.

If the system can tolerate the heat increase, then it is not a big problem.

So by reducing the flow through the FEL using 3/8 in hose, and then add another 3/8 port subplate in series, the heat goes up, but then again, if the system can handle it , then no big problem.

You are already using the 3/8 hose from the FEL to supply the rest of the hyd system, and even if the flow is reduced to the 3pt, that only affects speed. The cyl will still develop the pressure.

So I say this again, if the hyd system has been working all this time with the FEL using 3/8 hose, it should still work OK.

For a base line measurement, before you install the new valve, take some temp readings of the hyd fluid after a good work out, and use that to compare that after the new valve install.

Your 3pt will work the same.

Even the engineers don't get it right the first time, they usually have to have the technicians work out all the problems.

 

[irsmun]

Ah... which explains why the subplates are usually large aluminum blocks. They are heatsinks as well. So is the pump giving consistent PSI but varied flow rates based on engine rpms? or is both the flow rate and the PSI varying according to the engine speed?

 

[J_J]

The hyd flow is in GPM's.

The pump is rated for a certain pressure, but it is the resistance to the flow such as fluid flowing into a cyl or hyd motor which develops the pressure.