Tier IV Starting Procedure - mCRD engines

[dickfoster]

I was under the impression from my dealer that fluid is always being pumped and when you put the FEL into float, it kinda acts like a by-pass and fluid is able to circulate/move.

I was under the impression that unless you're actually putting pressure on the cylinders to lift the bucket, the oil bypasses the valve and is in circulation anyway whether in float or not. The oil is trapped in the cylinders under pressure by the valve when the bucket is lifted. As liquids can't compress the bucket simply stays there. But in float all pressure is released and oil from the pump flows straight to the tank to be recirculated by the pump. So in general unless some movement and work is being done by the hydraulics, the oil is always circulating under low pressure.

 

[buickanddeere]

The open center control valve is still going to be wide open from the inlet to the outlet port when the valves are in the neutral or float position.

 

[Jabonee]

I was under the impression that unless you're actually putting pressure on the cylinders to lift the bucket, the oil bypasses the valve and is in circulation anyway whether in float or not. The oil is trapped in the cylinders under pressure by the valve when the bucket is lifted. As liquids can't compress the bucket simply stays there. But in float all pressure is released and oil from the pump flows straight to the tank to be recirculated by the pump. So in general unless some movement and work is being done by the hydraulics, the oil is always circulating under low pressure.

You Are correct,however, the porting on the lift spool allows pressure oil to pass through to the 3pt valve while in float to do work. In float the rod and base hose ports are open direct to tank hose. :thumbsup:

 

[JerryK]

I'm a pretty good electrician, can hold my own with rough carpentry/millwright work/passable welder, pipefitter, etc.... But hydraulics drives me nuttier....

 

[jmh1783]

It would be good to know if there is a better way to get the hydraulics warmed up. I use the same startup procedure JerryK does. One click to the right, wait for the grid heater light to go out, then crank it up. It's worked so far as cold as 15F. I haven't tried in anything colder. Mine also has the turn left option but I've never been quite sure how that was supposed to work. As someone else mentioned, if you do that then try to start it you are one bad tick mark closer to the MIL light coming on.

 

[buickanddeere]

Plug in the block heater instead of attempting stone cold starts

 

[rokit]

It would be good to know if there is a better way to get the hydraulics warmed up. I use the same startup procedure JerryK does. One click to the right, wait for the grid heater light to go out, then crank it up. It's worked so far as cold as 15F. I haven't tried in anything colder. Mine also has the turn left option but I've never been quite sure how that was supposed to work. As someone else mentioned, if you do that then try to start it you are one bad tick mark closer to the MIL light coming on.

Other than the block heater or a generic electric fluid heater in the reservoir, not much you can do with a stock setup to warm the hydraulics quickly.

If you wanted to get fancy and mess with the tractor a bit, you could add a heat exchanger. Old Cummins 12-valve engines which were paired with 727 transmissions in some trucks had such an arrangement: the heat exchanger ran the transmission fluid through a coil immersed in the engine coolant ahead of the intake side of the radiator. Hot engine coolant would warm up the tranny fluid. The sizing is of course critical so that you don't overheat the trans fluid after warmup is complete (or you could have a manual shutoff).

 

[mike69440]

I blew my hydro oil cooler on my 2555 early this season. luckily they covered it under warranty. So now, I leave my FEL in float while my tractor is warming up. Helps circulate the hydro oil to warm it up.

Just FYI. In Sub Zero weather the back pressure on the loader valve, Float or not is near 500 psig.

I got to put in synthetic oil, thinner at low temperatures. I swear the TSC premium stuff is like gear oil cold.

 

[Kentuckyfarmer]

Other than the block heater or a generic electric fluid heater in the reservoir, not much you can do with a stock setup to warm the hydraulics quickly.

If you wanted to get fancy and mess with the tractor a bit, you could add a heat exchanger. Old Cummins 12-valve engines which were paired with 727 transmissions in some trucks had such an arrangement: the heat exchanger ran the transmission fluid through a coil immersed in the engine coolant ahead of the intake side of the radiator. Hot engine coolant would warm up the tranny fluid. The sizing is of course critical so that you don't overheat the trans fluid after warmup is complete (or you could have a manual shutoff).

I'm pretty sure that was something dodge came up with and wasn't a cummins engineer thing. I had a 90 3/4 ton with a auto that had it. The mechanic said it was a trans cooler. Instead of the trans oil going to the radiator like Chevy did dodges big idea was to have a separate cooler and not built in the radiator. I don't know if when starting it cold if the trans fluid warmed up quicker than the coolant did just sitting warming up. Those old 1st gen cummins with the ve pumps stock couldn't get out of their own way but a little tweaking of the pump made a big difference. Had 90 some thousand on the clock and the frame under it was rotted completely out. Only thing left worth anything was the motor.

 

[RBaldwin]

I was under the impression that unless you're actually putting pressure on the cylinders to lift the bucket, the oil bypasses the valve and is in circulation anyway whether in float or not. The oil is trapped in the cylinders under pressure by the valve when the bucket is lifted. As liquids can't compress the bucket simply stays there. But in float all pressure is released and oil from the pump flows straight to the tank to be recirculated by the pump. So in general unless some movement and work is being done by the hydraulics, the oil is always circulating under low pressure.

I asked this specifically since my 4025 said to wait till glow plug warmed up. He said the new engines don't need to do this unless its below like 40 degrees. If it's warmer then that just crank it like a gas engine.