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Adding a pony motor to a M936

Ferroequinologist

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Daniel,
I have the exact same problem logging in at work too. The IP changed, and the internet provider reclassified the site. I have tried to get it reclassified with no luck. I used to get on the site many times a day but not since the server replacement.

Doghead and I discussed this idea at length awhile back to get my m543 with the m936 bed running. A MEP002 was our best option. As Ron pointed out, you need almost a 20hp electric motor to run the pump with the same amount of torque as the stock setup. A 20hp motor is not little by any means. And require a large amount of electricity to run. I was going to remove the passenger fuel tank and mount it there, and plumb the engine into the fuel tank and the electrics into the trucks batteries with a start switch on the dash. It would definitely save fuel and be way less noisy than that 250 screaming.

Sorry to hear about your engine. That really sucks. Good thing you found out this way before you were flying down the road on an important mission.
 

73m819

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Ron doesn't the pto spin at the same as the transfer high range? 939 has overdrive of 1.1 right?
Output at the transfer case is the same as the input to the transfer case, transfer case is out of gear when the hyd. are used.
 

patracy

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Daniel,
I have the exact same problem logging in at work too. The IP changed, and the internet provider reclassified the site. I have tried to get it reclassified with no luck. I used to get on the site many times a day but not since the server replacement.
I'm sorry, but when we switched hosts/servers, an IP change was unavoidable. :(
 

Csm Davis

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Mdmorgan considering that your engine is tore down this far and the problem you had with the cam I would think about doing a complete teardown just to check out all the rest it won't take that much more time and will give you piece of mind later.
 

3dAngus

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The wife and I were brainstorming last night and she came up with an idea that I think is brilliant. Instead of trying to mount an engine somewhere to drive the pump, mount an electric motor to drive the pump and mount a diesel generator where ever it is easiest to access. Think about it, the elecric motor would be way easier to locate due to the smaller size, speed would be infinatly adjustable, plus you would have a generator to run other equipment off of, like a welder or plasma cutter.

Thoughts?
If you want to borrow a 5KW, a MEP-002 on a trailer, and see if it fits the bill for ya, you can drop by and pick it up.
It's mounted on a M116 and ready to haul.
 

pctrans

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Wow, those pics bring back some bad memories...
I replaced all liners and pistons. Pulled a couple of the mains, but they looked near new. Also used 4-ring pistons vs. the 3-ring ones that were originally in the motor. 100_0561 (800x600).jpg100_0562 (800x600).jpg100_0564 (800x600).jpg100_0566 (800x600).jpg
 

Tow4

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Daniel,
I have the exact same problem logging in at work too. The IP changed, and the internet provider reclassified the site. I have tried to get it reclassified with no luck. I used to get on the site many times a day but not since the server replacement.
I'm sorry, but when we switched hosts/servers, an IP change was unavoidable. :sad:
I got to ask, what did the site get classified as that makes it get blocked?
 

trukhead

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I wonder if a good DC welder like a mig welder that has settings for up to 24 volts would run a DC motor within its duty cycle time. Maybe start and stop the motor with a contactor to keep the welder fan running to cool the transformer.
 

Ferroequinologist

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a 20hp 220vac motor (what is required to run the wrecker pump under load) would draw 746 watts per hp, so 746 x 20 would be 14,920 watts. BIG generator would be needed, unless you were fine using a smaller HP motor and just waiting forever for the crane to move and cutting the load capacity.
 

trukhead

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You must consider the RPMs on the motor at operating speed and the hydraulic pump operating speed as well. I presume the pump operates off of a pto in the 600 to 1000 rpm range and the electric motors of any persuasion operate in the 1750 to 3600 rpm range. You need a smaller displacement pump running faster or the large displacement pump (the one on the truck) running slower to duplicate the pressures and operating parameters of the system as designed. The big pump run 3xs faster will wreck something.
 

Ferroequinologist

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You must consider the RPMs on the motor at operating speed and the hydraulic pump operating speed as well. I presume the pump operates off of a pto in the 600 to 1000 rpm range and the electric motors of any persuasion operate in the 1750 to 3600 rpm range.
Nope, it runs 1:1 with the engine RPM, and in a M936 when the lever is engaged for the pto, the air throttle sets the engine to 1800-2000 RPM. That's a common speed range for electric motors. However you still need the HP to provide the pressures needed when under load.

You need a smaller displacement pump running faster or the large displacement pump (the one on the truck) running slower to duplicate the pressures and operating parameters of the system as designed. The big pump run 3xs faster will wreck something.
Uh, the pump that is on the truck doesn't need to run any slower, it needs to run the speed it already does, as it is designed to run to power the crane within the parameters.
 
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Csm Davis

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a 20hp 220vac motor (what is required to run the wrecker pump under load) would draw 746 watts per hp, so 746 x 20 would be 14,920 watts. BIG generator would be needed, unless you were fine using a smaller HP motor and just waiting forever for the crane to move and cutting the load capacity.
Dear Ferro not doubting what you say here at all but a where did you find this and would a 20hp fuel burner cover this as well?
 

73m819

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Nope, it runs 1:1 with the engine RPM, and in a M936 when the lever is engaged for the pto, the air throttle sets the engine to 1800-2000 RPM. That's a common speed range for electric motors. However you still need the HP to provide the pressures needed when under load.



Uh, the pump that is on the truck doesn't need to run any slower, it needs to run the speed it already does, as it is designed to run to power the crane within the parameters.
-10 calls for 1250 to 1800 engine rpm for 936 rear operation, this is a 1 to 1 output at the transfer case pto
 

Ferroequinologist

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Back when I was going to move my pump onto an MEP motor, I actually contacted the manufacture of the hydraulic pump used in a M936 and got the 18hp via diesel engine at 1800rpm straight from a service rep to match the M936 bed required pressures and flow. 18hp electric motors are not that common to find, and they aren't usually as torquey as a diesel engine, hence me saying a 20hp electric motor.

Ron, I didn't look up the TM, I went by the 5 M936's I've operated. All ran from 1800-2000 when the PTO was engaged. I know the pump will work at idle, just won't boom up and the rest of the crane moved super slow. (engaged the PTO without air built up or the hand throttle pulled)
 
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