Ascinder's 1-Ton VX... Cont'd

[ZEUS]

Hey now! What I said was... Move the front axle forward & tilt the drivetrain downward at the t-case. Especially if you are still determined to move the drivetrain backward with a doubler! Then maybe you would not have to cut as much of the firewall & tunnel & your u-joint angle would allow you to pivot the 14B pinion up at the same angle. ...ok, I did not Say ALL that, but it was inferred! Haha I for one appreciate the detailed explanation of what you are buying and why. Did you basically research each part of the steering system and write out your own explanation of how it works in a build thread form in order to keep track of it all? Or is this part of helicopter service work? Something tells me you have been writing this section of your build for quite some time! Pretty funny that I was also the guy that said, "So moving the family to Montana is the most important priority, right?" Haha NOPE! SHOP TIME! "It's winter", he says.

BTW... I never told you this but the last time I was at your apartment I noticed all those books in your book case... Mathematics, Metallurgy, Mechanics, etc... yet the one book I picked up was about Physics... imagine my surprise; hidden within it was a Hustler magazine! Haha BUSTED!

What 3D program are you using?

[Ascinder]

Did you basically research each part of the steering system and write out your own explanation of how it works in a build thread form in order to keep track of it all?

Yeah, pretty much that. I need stuff like this for me as much as anyone else. Trying to keep track of all the moving parts and specs over the years takes a toll. Especially when you consider how many other projects I have. It also gives me some insight into how and why I made my decisions when I look back at it over time. If new tech materializes or something is found to work differently I can instantly compare without having to try and dig up old specs and research on the net.

Hey now! What I said was... Move the front axle forward & tilt the drivetrain downward at the t-case. Especially if you are still determined to move the drivetrain backward with a doubler! Then maybe you would not have to cut as much of the firewall & tunnel & your u-joint angle would allow you to pivot the 14B pinion up at the same angle. ...ok, I did not Say ALL that, but it was inferred!

I think I am going with a double cardan (CV) driveshaft front and rear. It requires you to point the axles and pinions directly at the transfer case yokes while the transfer case yokes stay at zero degrees.

Here's a "regular" setup:





Here's a double cardan "CV" setup:






CV driveshafts also allow a lot more articulation than conventional setups. The pinion angle on a CV driveshaft is a good thing as well as it pushes the vulnerable pinion up away from the rocks.

Up front it is a bad thing for me because between the caster angles the kingpins are supposed to be set at(usually ~6-8 degrees but can be 15-20 degrees on full hydro setups) and the pinion angle being pushed up towards the transfer case yoke, the behind the axle hydro steering setup I am planning on running might be out of space and fighting angles that may not work out. That's next up in the 3D modeling box.

For driveshafts, the two front runners I am considering are Tom Woods and High angle Driveline. they both make "over the top" shafts that excel at both strength and articulation.

Something tells me you have been writing this section of your build for quite some time!

Nope, all in my head, just hadn't committed it to a post. It took me a couple hours at work to pull all the associated resources. I need to get a "manual" created for this build, again so I can keep track of all the various part numbers, fitting sizes, dimensions, torques, etc. Some of these things can be difficult to track down later, and if something breaks or needs replacement, you at least have a starting point.

Pretty funny that I was also the guy that said, "So moving the family to Montana is the most important priority, right?" Haha NOPE! SHOP TIME! "It's winter", he says.

Montana is still on the table, and it would be easier to work on the VX with no interference and more space....

BTW... I never told you this but the last time I was at your apartment I noticed all those books in your book case... Mathematics, Metallurgy, Mechanics, etc... yet the one book I picked up was about Physics... imagine my surprise; hidden within it was a Hustler magazine! Haha BUSTED!

That was being used as a bookmark I swear!

What 3D program are you using?

An old copy of Sketchup 2015, nothing special. Here's where I left off last night. The crossmembers are very rough because there is no good data on them. If I remember and if I still care, I will try and clean them up a bit once I'm home at some point and can get measurements.

[Ascinder]

Small update:

-I picked up the brake caliper mount brackets for the 14 bolt(rear) axle
-I picked up an NP241 HD transfer case to use as a donor for the guts of the doubler.
-I finally pulled the trigger on the NWF Ecobox doubler kit
-I grabbed 100% of the suspension link brackets. Purchased across 3 different vendors with plenty of creative modifications still to be performed.

I made some good progress getting some of the 3D models for the engine and both axles, but unfortunately, they are just too taxing for my little laptop to run. Parts for a new computer build are on the way. Hopefully i will make some progress there in the next week or two.
In the meantime, I would like to solidify the full hydro steering and keep my eye open for deals on ORI struts and lockers.

Here's the progress on the virtual build. It's sitting at expected ride height on 37's with a ~19" belly. The rims are correct, but the tires are Trepadors instead of Creep Crawlers. The engine is still sitting up very high because it takes my poor laptop a minute or two to recover from literally every move I make. New computer case showed up today and the rest should be here in a couple days, then we can really start hitting it hard.

[Ascinder]

Some good news and some bad news.

I got all the computer parts in and assembled everything and it worked like a champ! Then I went and tried to update the BIOS and it didn't take and it was black screen of death from there on out. Motherboard is currently in transit for repairs, so likely two weeks out and two weeks back best case scenario.

Other than that, I finally decided on a ram and went with the Trail Gear Rock Assault HD ram. After seriously trying to get the surplus center ram to work out, I decided it wasn't worth the headache and went with the TG ram. I ordered the heim joints and tube adapters for it as well. I went with QA1 rod ends, PN HMR12HT and HML12HT. They are 3/4" hole x 3/4-16 threads and static rated at 52,900 lbs.




Here's the tube adapters:



On the rest of the steering, I went round and round(and round) with the pump and Orbitrol selection. I am thinking about ditching the KRC pump and going with an actual hydraulic pump. These pumps are used in industrial settings and can push out significantly more pressure and volume than an automotive power steering pump. They also run cooler and last longer. There are however several issues with fitment. They are a bit larger and they aren't designed for over hung loads. In other words, they can't take forces from the side (like a belt driving a pulley for instance). So we need an intermediate bearing and it has to be supported. I think this can be easily done with a simple pressed on bearing into a thick aluminum plate. The pump would bolt into the plate and the protruding shaft, now supported, would be easy to throw a pulley on. The next problem is mounting them. They are closer to the size of an alternator or A/C compressor than they are to a power steering pump. I can relocate my current A/C pump up high and to the passengers side with a relocation bracket and run the industrial pump in it's place. Why not just run the industrial pump up there you ask? Couple reasons.

-Putting the hyd. pump down low allows gravity to help keep it fed.
-It puts the pump(remember, the high pressure part) further away from the cab
-The hyd. pump has no electronics(unlike the A/C pump) and so if it gets submerged, no one cares
-The hyd. pump is noisy, so now we have it down low and away from the cab
-And most importantly, it allows us to use the A/C portion of the crank pulley. The crank pulley has two drive sections. One for the A/C, and one for literally everything else. The hyd. pump draws a lot of horsepower, especially at high rpms. Having it hooked up with everything else is a recipe for trouble. This layout isolates it and gives it it's own dedicated belt.


The Orbitrol is a tricky one too. Probably the trickiest part of the whole system. There are a blinding array of options out there and to make matters worse, choosing one option changes or negates others. The orbital is the "steering box" of the system and so out of everything, we want it to work, and work well. One of the main reasons I was pushed away from sticking with the KRC pump was that even maxed out, it only put out 1650 PSI and barely 3 gallons per minute of flow. To simplify things, the psi is how hard you can make the ram(and by extension, the wheels) push. You can literally knock boulders over with one finger with full hydraulic steering. The gallons per minute(gpm) rating is how much flow you can push through your ram. This is important for steering response. When we try and turn the wheel fast (like in a dangerous situation) we want the pump to be able to keep up. As the ram sizes go up (mine is one of the larger ones) this becomes more important. The gear driven pumps put out serious psi and flow. They start around 3000 psi and can flow up to 10 times the flow of the KRC pump. We don't need anywhere near that much flow, but what we do need is enough flow to be able to run a "proper" Orbitrol". Remember earlier how I said some options wouldn't allow others? Well it turns out the low flow and psi of the KRC pump was significantly limiting my options for the Orbitrol. One of the cooler options available is dual rate steering. You basically flip a switch and your steering goes from 5 or 6 turns lock to lock(like stock steering, and less twitchy at speed) to 2 turns lock to lock, which is great for slow speed response and doing technical stuff in the rocks. It turns out most the the safety features are only available on the higher flowing, higher pressure models as well.

[PK]

A few words of caution with sizing up your power steering, from a Fluid Power Engineer with 45 years experience in circuit design, including power steering circuits.

1. Will you be driving this vehicle on the roads?? In Australia, and most of the rest of the civilised world, Orbitrol units are not legal for on road use. Stupid but true. The Orbitrol units do not have the safety features supposedly found in the sector and ball-nut type power steering boxes.

2. Try and find a larger flow dedicated power steering pump if your first choice is not large enough. 5 and 7 GPM power steering pumps are readily available, and still have all the inbuilt features that a commercial gear pump won't have.

3. If you have to go to a commercial pump, try and find a high speed vane pump, rather than a gear pump. Do not under any circumstances use a gear pump with an aluminium housing. They cannot support the sustained heat and high pressure, nor the high revs.

4. You are correct that a commercial pump is not normally built to take side loads like a belt drive. Your idea of an aluminium plate with a bearing in it, is very limited. Most pump shafts are too short to protrude through the aluminium plate and still engage the belt pulley. To use your idea you will also need a stub shaft made to extend the pump shaft - female to mate with the pump, male to mate with the pulley. Some commercial pumps can be ordered with an "overhung load adapter" built into the pump housing. This does allow them to take the belt drive side force.

5. A dedicated power steering pump has 2 vital valves built into the pump. A pressure relief valve, and a pressure compensated flow control valve. If you use a commercial type pump you will have to purchase, mount, and plumb up these 2 extra valves.

6. Don't forget that the larger the commercial pump flow, the larger the reservoir required. Rule of thumb is 3 x GPM for the reservoir size. This can be reduced down to 1 x GPM if you install an additional cooler. Dedicated power steering pumps use some internal trickery to get away with smaller reservoir sizes. They also use longer routing of the return lines to allow heat to dissipate prior to returning to filter and reservoir.

7. Whatever you do, work out your actual flow calculations very carefully. Engine RPM range, dia of crankshaft pulley and dia of pump pulley and the displacement of the pump in cubic inches/rev (or cc/rev) should give you the right answers. You need enough flow at idle to slowly turn your steering, and not tooo much at high engine revs.


That is probably enough for now.
If you need any help sorting through the options of the Orbitrol units give me a yell. Unless you have been especially trained in military driving techniques, avoid any orbitrol unit that will give you live feedback. Otherwise you will break your thumbs as the road wheel hits a rock and the steering wheel spins uncontrollably out of your hands.


I have been retired for a few years now, but still do some consulting work when I am dragged back for particular problems.



PK

[Ascinder]

A few words of caution with sizing up your power steering, from a Fluid Power Engineer with 45 years experience in circuit design, including power steering circuits.

1. Will you be driving this vehicle on the roads?? In Australia, and most of the rest of the civilised world, Orbitrol units are not legal for on road use. Stupid but true. The Orbitrol units do not have the safety features supposedly found in the sector and ball-nut type power steering boxes.

This has been gone over earlier in the thread and on other forums ad nauseum. The DOT does not specifically prohibit hydraulic steering, but does stipulate that steering must be connected through a mechanical linkage. We have garbage trucks in the states that steer purely through hydraulic steering so it is being done somehow. Most police here don't know and don't care about any obscure legalities regarding this.

2. Try and find a larger flow dedicated power steering pump if your first choice is not large enough. 5 and 7 GPM power steering pumps are readily available, and still have all the inbuilt features that a commercial gear pump won't have.

Most higher flow pumps that I have come across are just hot rodded (bored out) conventional power steering pumps. They burn out under full hydro use very often and are expensive to replace. What inbuilt features are you referring to? Several of the gear pumps I have looked at have built in flow and pressure regulators. What would a conventional pump have/need besides those?

3. If you have to go to a commercial pump, try and find a high speed vane pump, rather than a gear pump. Do not under any circumstances use a gear pump with an aluminium housing. They cannot support the sustained heat and high pressure, nor the high revs.

The things I have read point in a completely opposite direction. The aluminum dissipates heat better than steel. My "high performance" KRC pump is aluminum with the steel pump being half the price. The manufacturer told me they went to aluminum because the steel wouldn't hold up at high rpm/heat. The gear pumps I have looked at are all rated well over 3000 psi and 4000 rpm constant speed. Manufacturers have stated in letters that they are able to sustain higher rpms for short periods with no problems. Several people have been running these pumps in this fashion for years with no ill effects. The gear pumps(and a fair amount of vane pumps can be had for ~$100. Versus replacing a ~$3-400 suped up power steering pump at about the same rate, I'll take my chances with the gear driven models(although the vane pumps are fine too I understand they don't do as well at high pressure or life expectancy)

4. You are correct that a commercial pump is not normally built to take side loads like a belt drive. Your idea of an aluminium plate with a bearing in it, is very limited. Most pump shafts are too short to protrude through the aluminium plate and still engage the belt pulley. To use your idea you will also need a stub shaft made to extend the pump shaft - female to mate with the pump, male to mate with the pulley. Some commercial pumps can be ordered with an "overhung load adapter" built into the pump housing. This does allow them to take the belt drive side force.

I have looked into this as well. A half inch thick aluminum plate simultaneously mounts the pump and provides a pocket for the bearing. The bearing is a ~$30 NTN deep groove single roller bearing rated at thousands of pounds of load and tens of thousands of rpms. It is under 3/8" thick. The pump shafts I am looking at would protrude through the plate and bearing with 3/4 of an inch to spare. Even more if you consider that the bearing only needs to be retained with a small lip around the rim so the pulley would be able to mount right up to it "into" the aluminum plate. This eliminates the need for a stub shaft and all its additional complications. The pumps I have seen with overhung load adapters have all been clutched units which cost 7-8 times as much as the unit I am considering.

5. A dedicated power steering pump has 2 vital valves built into the pump. A pressure relief valve, and a pressure compensated flow control valve. If you use a commercial type pump you will have to purchase, mount, and plumb up these 2 extra valves.

See comment above. These two are included in the pumps being considered. They are also duplicated in the Orbitrol valve as well. Being open center with a power beyond port, the Orbitrol only uses what it needs to steer(both pressure wise and flow). Everything else is bypassed straight back to the reservoir(via either the open center or power beyond port).

6. Don't forget that the larger the commercial pump flow, the larger the reservoir required. Rule of thumb is 3 x GPM for the reservoir size. This can be reduced down to 1 x GPM if you install an additional cooler. Dedicated power steering pumps use some internal trickery to get away with smaller reservoir sizes. They also use longer routing of the return lines to allow heat to dissipate prior to returning to filter and reservoir.

Most of these setups(off road hydro steering) run reservoirs sized at about 1 quart. Needless to say, they overheat and it causes issues. One of my first inclinations was that the cooling was way undersized. I am confident the 5 gallons of fluid will be more than enough for my needs. I am infrequently moving a (very) small ram compared to something like an excavator which needs to do it all day long with many large hydraulics loads. The way power steering pumps deal with excess is by internally recirculating fluid. It does cause heat when the systems are under high pressure. The Orbitrol constantly circulates fluid through the entire system, not just internally. Being that I am planning on a 5 gallon reservoir, there are very few places to install it. It is likely going near the back of the vehicle. The lines will be plenty long enough to cool the fluid. A couple heater cores will likely be employed to help cool as they are rated for much higher pressure than conventional radiators. System sizing also plays a huge role in heat generation. Many systems are sized too small and the restrictions cause excess heat. I am going bigger than required on everything, so comparatively, my system will be lower pressure and lower flow than I need.

7. Whatever you do, work out your actual flow calculations very carefully. Engine RPM range, dia of crankshaft pulley and dia of pump pulley and the displacement of the pump in cubic inches/rev (or cc/rev) should give you the right answers. You need enough flow at idle to slowly turn your steering, and not tooo much at high engine revs.

Already done, but the problem isn't in the numbers I get, it is matching it up to the configurations that work with the Orbitrols. My crank pulley is a 25% underdrive unit. With a 6.5" pump pulley, it gives me a ratio of .86 for rpms that the pump sees. My engine is putting out 550 horsepower. At 2,800rpm I am putting out what the stock VX puts out redlined. Pushing my numbers up to 5,000 rpm, I am only turning the pump at 4300rpm. Most regular vehicles seldom see 5,000 rpm, let alone most V-8's. For the very small amount of times the pump will see high rpms and the even smaller window of time it will be exposed to them, I think I'll be OK. Based on my gear calculations, at 3,000 rpm, I am hitting 110 MPH in 5th gear. The problem with these systems is we often need the most flow and pressure when we are going slowly and th least when we are driving fast. I have a PTO capable of driving a separate pump and I was considering that route, but it greatly complicates the steering circuit and seems like a compromise. I personally do not want much flow. In steering, flow equals steering responsiveness/speed. I would prefer a normal amount of turns lock to lock under normal conditions and a lower amount, but still precise while going slow in the rocks. It seems like it could be accomplished through either some Orbitrol trickery or by just throwing some check valves into the circuit to force the KRC pump to go into bypass mode while the high PSI, high flow PTO pump takes over.

That is probably enough for now.
If you need any help sorting through the options of the Orbitrol units give me a yell. Unless you have been especially trained in military driving techniques, avoid any orbitrol unit that will give you live feedback. Otherwise you will break your thumbs as the road wheel hits a rock and the steering wheel spins uncontrollably out of your hands.

I have actually been trained in special military driving techniques, and I can tell you a rig with running large tires and tight steering offroad will break your fingers off every bit as quick as a hydro unit.

I have been retired for a few years now, but still do some consulting work when I am dragged back for particular problems.

For reference, here is where I am getting a good portion of my information:

LINK