reverse rotaton pump mount

[muddstopper]

I have two section hyd pump, I want to mount on a 7.3 international engine. Pump is 75gpm combined. shooting for 3000psi, but might be able to get by with less pressure. Anyways, the engine is coming out of a old international truck, Tranny is shot before someone suggest using the transmission to reverse shaft direction. And no the rotation direction cant be changed, without buying a lot of expensive parts. I would like to mount the pump at the rear of the engine, but I would have to build jack shafts and use belts and pullies to make that work. Second thought is to just mount the pump on the front of the engine using a short drive shaft with universal joints. My concerns with mounting at rear of engine is the possibility of slipping belts. 75gpm oil at 3000psi, would take some power to pull. I could use vee belts, but not sure to how figure out how many vee's I would need. Probably a chart somewhere on the net, I'll have to search for it. Also side loading on the pump shaft would make me worry. My second thoughts are mounting the pump on the front directly to the crank. I have seen a ton of hyd pumps set up this way, but nothing the size I plan on using. I am wonder if the crank keyway will hold up, and will the front engine bearing take the stress. I can make a mount for either end, just wondering which method would be the best to use.

 

[IceStationZebra]

That flow and pressure work out to ~130hp. You didn't state what RPM you intended to run the engine at which has a huge effect on the torque, which will determine if a key might work and what size couplings would be required. You might consider just using one coupling to eliminate the universal joints, but alignment is critical. It would also be helpful to understand the duty cycle of the pump - constant load or constantly changing.

A quick look at a Gates V-belt application guide shows that you can probably run belts off of the back. The advantage here is that you can optimize the engine RPM. Under max load the torque peak is at 2000rpm, which should be the most efficient. Another thing to consider is if the engine will get pulled down or has to start under load. Unlike electric motors, engines don't generate a lot of torque at slow speeds so they can struggle. The rule of thumb I've seen range from 1.4 to 2.0 times the horsepower of the pump.

powerstrokehub.com/7.3-power-stroke.html

ISZ

 

[bigdeano]

I've seen when they run a supercharger off the front of the engine they sometimes drill a hole in from the front of the crankshaft so it's half in the crankshaft and half in the pulley. Then they use a dowel pin as an extra key. You can probably find info about it with a little searching. I think they use a drill bushing setup to get the hole straight.

 

[muddstopper]

Pumps are a Sauer gear pump and needs 1750rpms to get the advertised flows. The smaller section of the pump will run a axial piston hyd motor.. The larger section will provide flow for a pair of 4.5in bore cyl. I intend to combine the flows after the hyd motor to provide the full 75gpm flow to the cylinders. Since the hyd motor will use a lot less pressure than the cyl, I will set it up as a high/low system by using a unloader valve to dump motor oil back to tank once a set pressure is reached. Sort of like a two stage wood splitter pump. Motor will get full flow of smaller pump section at 2000psi +/- when in use, then be diverted to unloader valve where it will combine with large pump section to provide the extra speed of the cylinders and dump back to tank when unloader setting is reached, 2000psi+/-. The larger pump section will provide full flow to the cyl at 3000+/-psi. Control vavle for cyl is a parker v70 rated at 70gpm. There will also be another double section pump, of around 14/5gpm to run other functions. The smaller 5gpm will to to run a continous conveyor, the 14gpm to run a small knuckle boom. The knuckle boom will not be in use while other operations are performed.

My plans where to run the smaller 2 section pump off the front of the engine, and the larger pumps off the rear. The smaller pump I thought I could get just became unavailable yesterday, so i have to regroup a little and look for another pump. The larger pump also being reverse rotation kind of thru a kink in my plans as well. Since this project is being built on the cheap, the pump I have is the one I will use. I can machine a stub shaft to fit the flywheel to put pullies on. Not sure if hyd pump can stand the side load of a belt drive.

 

[Whatswrong]

If I was creating this I would definitely go off the rear ,would you be able to use chain and reduce side thrust issues. Can you extend the shaft at the rear and run both pumps from there? I guess I am hesitant to run stuff off the front unless I know it has been industry proven satisfactory.

 

[Rustyiron]

Is this for your (iirc) log loader?

 

[muddstopper]

Is this for your (iirc) log loader?

Yea, this is for my firewood processor. I have been laid up for a while and just now getting back to the build.

If I was creating this I would definitely go off the rear ,would you be able to use chain and reduce side thrust issues. Can you extend the shaft at the rear and run both pumps from there? I guess I am hesitant to run stuff off the front unless I know it has been industry proven satisfactory.

What I am considering doing is making a stub shaft to bolt to the flywheel. Mount a timing belt pulley to the stub shaft to run a jackshaft, and mount one pump to each end of the jackshaft. Not a perfect setup, but cheapest way I can think of.

 

[Rustyiron]

Yea, this is for my firewood processor. I have been laid up for a while and just now getting back to the build.

Glad your back,:thumbsup: don't forget we need our pictures!

 

[muddstopper]

Paid for the donor truck today, might be a few weeks before I can get it home and pull the engine. Nothing but rain here, after a summer of drought. We need the rain, I just wish it was spread out a little more evenly instead of all at once. I have a plan for mounting the pumps at the rear, but got to make sure nothing interferes with starter location first. I have a decent cab and chassis to get rid of if anyone needs parts for a 89 international truck. Transmission is suspect, but 2sp rearend is good and has air brakes. Will have a clear title to go with it as well. I will be using the engine and related parts, including the air compressor and air tanks and the fuel tank, but everything else will probably go for scrap.

 

[oldnslo]

What size is the crank shaft? Compare that to your pump shaft. This should give you some idea on whether the crank would take the load. Very common to have a short drive shaft with u-joints running pumps in this manner.

 

[muddstopper]

Not having to measure to know the engine crank is much bigger at the rear than the pump shaft. Not sure if crank is cast or forged. At any rate if the crank can pull a 2 ton truck loaded, I am reasonably sure it will pull a hyd pump. Now if your talking about using the front of the crank for direct coupling of the pump, there would be a major difference in bearing size of the crank between front bearing and rear bearing, and just assuming a 7.3 crank is similar in design as a gas engine, the end of the crank is machined down to accept the harmonic balancer and might not be much larger than the pump shaft. I too have seen a lot of engines with pumps mounted on the front, trash trucks, ditch witches and farm tractors to name a few. A few concerns I have, granted I dont have the engine setting in my shop to actually look at, would be pump clearance. A double pump is pretty long by design, using a universal joint coupling or even lovejoy type, would make it stick out even further from the engine. Then you still have to have room for the radiator, or raise the radiator so the pumps will fit under it. I havent decided which way I will go yet for mounting the pump, just have to get everything in the shop and sort it out. I am heavily leaning to making a mount to put the pump on the rear. The 7.3 medium duty trucks use a adapter between engine and transmission to accept a sae 2 or 3 bellhousing. I am hoping I can build off this adapter, but I havent actually looked at it so who knows.

 

[CJONE]

I haven't seen a cast crank in a large diesel or any diesel for that matter. 2000 and up are PM rods but that is not a issue for you. Your going to have to keep the engine at the desired RPM and we have always done that with a pto [electronic] controller in the ford 350-550 trucks I normally work on. I have had a few 7.3's apart and if you drive the pumps directly inline with the crank you should have no issues with the front main. If you run your pumps at 3k you will need 150 EBH and you will be hard pressed to belt drive it and I would be worried about the front main taking that much of a side load. Rear drive with a chain coupler and solid mounts would be fairly simple but is that the right rotation for your pump? CJ

 

[muddstopper]

Yea, the guy I got the pump siad it was reverse rotation, and I am sure he knows as he's been building and designing big equipment for years. Before he sent the pump to me, he took it apart to change rotation and said it couldnt be done without buying parts that cost as much as the pump. Pump was a freebe, so its what I am going with.

Pumps only need to turn 1750rpms to get advertised flows, I am sure I could turn the rpms up if I thought I needed it, but its already borderline to big as it is. I believe the 7.3's peak hp at 2000rpms, so I should be pretty close to more than enough hp at 1750rpms. I will most likely just use a throttle stop and set the engine at 1800+/- rpms. Max hp shouldnt be needed as all funtions are short bursts of flow and then noload. Cyl retraction and should be at near nothing pressure wise and very seldom should the cyl see max pressure as they extend. I just about bet the unloader valve set at 2000psi will hardly ever have to unload. I just want the extra power for when I might need it and then the unloader will be dumping almost half the oil back to tank and the little larger section (about 42gpm) would build max pressure. So it isnt going to take all the hp the engine can produce. Probably wont need over about 125hp with everything maxed out which would be very seldom. I would have to be sawing at max pressure and at max splitting pressure to even get close. I dont think I can work that fast, or that hard anymore.

 

[oldnslo]

mudd,
I was talking about the front or fan end of the engine. Yes you have to work around the radiator and it does make the engine much longer. That is why the bumpers on cement trucks extend out so far.

 

[muddstopper]

mudd,
I was talking about the front or fan end of the engine. Yes you have to work around the radiator and it does make the engine much longer. That is why the bumpers on cement trucks extend out so far.

I have already been considering how to work around the radiator and havent came up with any good ideals. I think at a minimum, I would have to raise the rad enough to fit a drive shaft under it and that would put the pumps way out front of the rad. I would still have to mount pumps at the rear to run all the aux functions. Since the pump is reverse rotation, I think it would be better to just make some sort of belt or chain drive and turn the pump around and mount it beside the engine, I then could either drive the aux pumps from stub shaft on the engine, or the jack shaft for the main pump, or possibly, just depending on what aux pump I find, maybe mount it on the front of the crank. I would like to find another ditchwith backhoe attachment pump, like the one I had planned to use but let get away, for the aux circuits.

 

[bigdeano]

Maybe you could use some kind of gearbox on the back of the engine. That's a lot of hp for a belt drive.

 

[muddstopper]

I have been looking for a pump drive gear box, thinking I might find one on a old t9 dozer that might bolt to the back of the 7.3. I have found some new gear boxes, but I aint interested in paying the $7-8000 they want for a new one. I even thought about taking the inputs shafts out of a couple of transmissions and building a gear box. Not sure my machining skills are up to that task. Cant do much planning or building until I get time to get the truck home and the engine pulled and that might not be until spring. According to a few diesel sites, the 7.3 uses a SAE 2 or SAE 3, bell housing bolt pattern, which might make finding a pump mount gear drive a little easier. I just cant get a positive answer to the actual bell housing mount size or any detailed drawing of the bolt pattern for a 7.3.

 

[bigdeano]

Search for Velvet Drive transmission on ebay. They're boat transmissions. I think they have forward and reverse with the same ratio. Some of them are 1:1 ratio. They look pretty simple, but I don't know anything about them. Some of the used ones aren't very expensive.

 

[muddstopper]

Did a little reading on the Velvet drives. The model 71 seems to be the only one that is direct drive 1:1. One of those would probably work and I seen a few on ebay in the $300 range, used, so not that bad expensive. A few concerns I would have using one in my application is overall length. I would also have to come up with some sort of adapter to connect it to the engine crank. I would also still need to build some sort of mount for the pump and a driveshaft to drive it with. Time, work and money, I might still be better off to just build my own. My concern with doing a belt drive would be belt slippage, but I know of a few set ups on equipment where belts are used to power some pretty big variable pumps. I might copy one of those designs. If I recall correctly, there are two large, 80+gpm variable pumps behind a JD engine and there is either 3 or 4 belts to each pump, but I will just have to go back and look at it again to know exactly how its all connected. I have had to replace those belts a few times over the years, but that equipment runs 10 hrs a day 40 hrs a week and its several years between replacing belts.

 

[Rustyiron]

Tranny is shot before someone suggest using the transmission to reverse shaft direction.

I wonder if;
1 it has a PTO acess & if IT would still work
2 would it (pto) provide the proper speed for your pump.

Nou sure how you would check this for operation without actually bolting on a pto unit. Maybe a good trans guy would know. The pto "box" would not be that expensive a way to go if it would work.