Adding a pony motor to a M936

[tobyS]

Have you guys missed the engine powered hydraulic pump, self contained units that have sold on GL? They are 28 hp diesel and perfect for this use. Two circuits even... that can be combined for higher flow.

I want one for my project but they are just beyond my budget.

Or buy a log splitter and borrow that gas engine/pump setup for a while.

 

[Ferroequinologist]

According to the manufacturer, the pump has to turn 1800 rpm to produce the flow rate and pressures as specified for the bed. I'm not mathematically inclined enough to figure out if you had say a 10hp motor at 3600rpm running through a reduction gear box to 1800rpm if that would transmit the proper amount of HP needed. I still have the service reps number, I can call him next week and run some more questions by him.

I will also check around on Google and see if I can find the equations necessary to solve the problem.

 

[patracy]

According to the manufacturer, the pump has to turn 1800 rpm to produce the flow rate and pressures as specified for the bed. I'm not mathematically inclined enough to figure out if you had say a 10hp motor at 3600rpm running through a reduction gear box to 1800rpm if that would transmit the proper amount of HP needed. I still have the service reps number, I can call him next week and run some more questions by him.

I will also check around on Google and see if I can find the equations necessary to solve the problem.

Not picking on you, but gear reduction doesn't increase horsepower. Actually it will slightly decrease it due to frictional loss. BUT, it will increase torque.

 

[tobyS]

The pump will produce whatever pressure the bypass is set at. It's a gear pump, not pressure compensated variable displacement. So if the pressure relief is set at 1500 psi, no matter what driver is used, it will not relieve until that setting is reached...or it will stall the engine or electric motor if the HP is not high enough.

Do you know the pressure setting? How many functions at once do you need? You can use the highest flow requirement, like two 4" cylinders vs one motor with 7 (just an example) cubic inches per revolution for calculating. You must set an acceptable time too. If it elevated the boom in 5 seconds is 10 satisfactory for your need? Or do you want more speed (speed is flow, torque is pressure) than original? Can you wait 20 seconds for the boom to rise?

I understand the truck engine is down, but what do you want to accomplish with this pump? Is it a temporary thing?

 

[Csm Davis]

Ferro can you post the pump model and manufacturer? I can look up specs at the shop.

 

[mdmorgan]

I understand the truck engine is down, but what do you want to accomplish with this pump? Is it a temporary thing?

Answered earlier in thread.

 

[tobyS]

Yes the first post says you want to have a temporary fix to use it to change out your own motor. But it appeared the thread progressed to a system that would be permanent and have capacity comparable with the OEM (except for the posts about posting pictures). If all you want to do is change out your motor, then nothing but pressure needs to be determined and you wait as long as it takes for the speed part. That can be accomplished with a very small motor and pump that will have little to do with OEM specs since you have no time requirement. I integrate hydraulics and programmable controls so have some experience in hydraulic design and sizing.

 

[tigger]

Just peddle faster!

 

[Vintage iron]

I am buying a wrecker from my buddy and I would like to run the rear section off a pony motor. I have been following this thread, but it doesn't seem like we are getting anywhere. Can the rear crane and rear winch be run off a small diesel motor? What HP would it need to be? Would an electric motor powered by a generator/welder be a better option? I would be interested in running a trailblazer welder to power an electric motor

 

[Munchies]

I got a nice APU that would work for you guys. I think 'JesusGatos' has another he may or may not be using as well. Its from M88 tank recovery vehicles. Self contained Hatz diesel, hydraulic pump, and a 400? amp 24v generator. Nice little tight package. I scored a control panel for it as well, and contracted a defense contractor to make the wiring harness for it. Only thing its missing is the voltage regulator. (hard to find, either find one or retrofit something) and the hydro pump needs a rebuild.

 

[tobyS]

VI you will need to confirm hose sizes and pressures but here is a guess. To have laminar flow the fluid should move;

Pressure lines - 25 ft./sec.

Return lines - 10 ft./sec.
Suction lines - 4 ft./sec.

I will guess at a main pressure line with inside diameter (ID) of around 1/2" so looking at the table (at the above flows) I see there is a size .496 pressure line which corresponds to 15 gpm. (the recommended return is .782 ID" and suction is 1.239" ID). http://www.ihservice.com/PDF's/Tube Selection Chart.pdf


(flow x pressure)/ 1714 = pump HP.

Assuming 1500# pressure..............(15 x 1500) / 1714 = 13.127 horsepower at the pump.

Just to compare, a 5 kw generator makes around 6.7 hp so a 10kw gen engine would probably work. Do you have a 10 or 15 kw gen to donate an engine?

Compare my size and pressure assumptions to what you find and we can get real close.

 

[Vintage iron]

My buddy has this rebuilt Diesel engine. I think it would work great on the wrecker.

 

[Munchies]

A 6 cylinder seems kind of overkill and.large. the APU I mentioned is a 2cyl and it runs all the m88 hydraulics

 

[tobyS]

It's way overkill, I think. Can you confirm the pressure line size and operating pressure? That will give us a lot better idea of the HP.

That's a nice looking engine but I have powered an entire hydraulic drive sawmill with a 4B Cummins and had 70 gpm. I'm guessing it's 8-10x larger hp than you need.

Your main pressure line is key (easy to get at least OD), even if we guess at pressure.

 

[Vintage iron]

It is only a 60 hp motor. It would be better in a jeep though.

 

[tobyS]

I was thinking more like an engine from a 10 or 15 kw gen set that is beyond making work again for generating. Or an Onan 16 twin if gas, maybe a single cylinder large Kohler even...but it might be slow (or stall) if you don't have enough hp at the pump (or pump size is wrong).

 

[Vintage iron]

I like the idea of a Miller Trailblazer. Really nice units and then you have power and a welder on the truck.

 

[Munchies]

I posted the info from the M88apu at one point or maybe I sent it to Jesus gatos.. I will find it and repost here, and we can look at the specs on the pump.

 

[tobyS]

The only problem with the trailblazer is you will be turning the pump when welding unless you disconnect it. Personally I would not want to do that when a dedicated engine and pump could be rather compact and from my experience, I have to have a welder and crane operating at the same time, which would surely be a problem.

Munchies, is that the 2 cylinder diesel? And is it an entire functioning engine with pump, etc? If so, that would appear to be a good choice, probably around 15 hp.

It would seem that a non-functioning 10 or 15 kw generator would be a great donor...although may be 3 cylinder or even small 4. Which would bring us to small auto engine size as well. Like a VW diesel. Kobota too. How about a refer engine? They are compact and long life.

 

[ke5eua]

The APU on the 88 provides 24v and hydraulics but the apu can't provide enough power to run all the hydraulics on the 88.

The original 88 the apu powered the refuel, on the a1 they dropped the refuel capability but you could operate the aux winch and small tasks hydraulic items but not enough power to pull in the main winch and raise the boom.

To operate all the hydraulics in the wrecker you are better off just using the pto on the engine as the demand is greater than a small apu will give you.