Cold Weather Starting

[ponytug]

I would recommend something a little beefier for the hydraulic tank, like a magnetic heater. Plus, you won't have the main vent open for crude to fall in while you are heating it.

I have to admit that since Bob's posting on the high vacuum in the summer time, I have been running the PT a lot slower until the oil tank is warm. Thanks for the heads up!

All the best,

Peter

I have always had the same problem, But only when the temp goes under 10 degrees, This year I'm gonna try two dipstick heaters from Tractor Supply (cost under $20.00) One in the engine and the other in the hyd. tank.

 

[SpringHollow]

Okay, that is one thing that i question. The PT is always pumping oil right from start up. The only question is do you just let it return to the tank or do you use it. Is it because it is pumping against low pressure when it sends the fluid to the return that it is better to do that than say drive slowly?

Because the fluid heats up relatively quickly from just idling, it is clearly doing some work as it goes through valves, bypasses etc.

Ken

 

[J_J]

If you are talking about the hydraulics, the charge pump is always pumping about 10 % or total flow. Driving slow is OK, and will eventually heat the hyd fluid . Working all three pumps will improve the heat up time. You can be driving slowly, and making the FEL valve bypass, and if you had a hyd motor in the PTO circuit, all three pumps would be contributing to heating the hyd fluid.

 

[ponytug]

Dear Ken,

Here's my logic. If under cold flow the filter experiences significant back pressure, i.e. vacuum (per Bob999's post), then low engine rpms should minimize that the risk that the filter collapses, or that the vacuum gets high enough to cavitate. So why not run the engine at lower rpm until the oil is warm?

Since the charge pump is making up for leakage in the pumping circuit, it, as JJ notes, isn't pumping much volume, but it still can, and does, develop significant vacuum.

My thinking was that by not running at higher rpm, that the leakage from the drive motors is minimized, thereby minimizing the charge pump flow. Meanwhile, as you note, the PTO pump is running continuously and warming the oil, along with all of the return from the auxiliary pump plus any return from the motors. As you note, all of that moving oil generates heat. I'm just waiting for the oil to warm up before really revving the engine.

How's the logic?

Would a magnetic tank heater and warm oil be better? Without a doubt! But I don't always plan that far ahead. Perhaps one of those eksbar diesel heaters on the PTO overflow to warm the tank quickly...

All the best,
Peter

Okay, that is one thing that i question. The PT is always pumping oil right from start up. The only question is do you just let it return to the tank or do you use it. Is it because it is pumping against low pressure when it sends the fluid to the return that it is better to do that than say drive slowly?

Because the fluid heats up relatively quickly from just idling, it is clearly doing some work as it goes through valves, bypasses etc.

Ken

 

[Gravy]

I have always had the same problem, But only when the temp goes under 10 degrees, This year I'm gonna try two dipstick heaters from Tractor Supply (cost under $20.00) One in the engine and the other in the hyd. tank.

I tried a dipstick heater. It was a total waste of money and effort. Not enough wattage and not enough surface area = no noticeable effect.

I am using one magnetic block heater on the hydraulic tank and another on the top of the tram pump. The combination has made a useful difference. I would still like to find a way to heat the engine.

 

[Bob999]

Dear Ken,

Here's my logic. If under cold flow the filter experiences significant back pressure, i.e. vacuum (per Bob999's post), then low engine rpms should minimize that the risk that the filter collapses, or that the vacuum gets high enough to cavitate. So why not run the engine at lower rpm until the oil is warm?

Since the charge pump is making up for leakage in the pumping circuit, it, as JJ notes, isn't pumping much volume, but it still can, and does, develop significant vacuum.

My thinking was that by not running at higher rpm, that the leakage from the drive motors is minimized, thereby minimizing the charge pump flow. Meanwhile, as you note, the PTO pump is running continuously and warming the oil, along with all of the return from the auxiliary pump plus any return from the motors. As you note, all of that moving oil generates heat. I'm just waiting for the oil to warm up before really revving the engine.

How's the logic?

I agree with most of your logic with the exception of the underlined phrase. My understanding is that the charge pump flow is determined by engine RPM and that the charge pump flow goes to make up wheel motor leakage and the remainder flows through the hydraulic cooler circuit before returning to the tank.

 

[ponytug]

Do you ever look at an old post of yours and think, I could have phrased that better?

I agree with your clarification. Thanks!

I'll double check my plumbing; I had never thought to look where the excess flow from the charge pump went.

All the best,

Peter

I agree with most of your logic with the exception of the underlined phrase. My understanding is that the charge pump flow is determined by engine RPM and that the charge pump flow goes to make up wheel motor leakage and the remainder flows through the hydraulic cooler circuit before returning to the tank.

 

[J_J]

You really can't call it excess, in the fact that pump is a gear pump and is pumping when the engine is running, and at about 10% volume of the max tram pump volume. So, what ever is needed to makeup lost fluid because of wheel motor leakage, and if no lakage, the fluid is passed on through the tram pump case for additional cooling, and then to radiator. That is why, when you think of filtering, the GPM's that are filtered is the charge pump volume. If you have a 3 GPM charge pump, the suction filter can filter about 180 GPH at max engine rpm. At idle, the charge pump is working very little. So at idle, all 4 pumps are working pushing fluid. You could ad extra heat by makng a valve go to relief, and/or driving the PT.