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Heaph's Build Thread - Built not Bought

My question has nothing to do with clearance. It's about mathematics and what considerations have been done.

Look at a hydraulic engine lift. Mine is a 2 ton. With the arm fully extended it's rated at 500 pounds. The jack on it has an 8 ton rating. I can't tell you how it was all figured out but somebody sat down and did. Take any stock power assist steering. Parallel park with the tires against the curb and turn the wheel. You'll hear the pump load up but you don't blow seals, bend & break parts, etc. because somebody did the math.

There is a full hydro thread in this forum that's been active lately. If you read it several people have broken parts for various reasons but a lot of hit & miss engineering. What guidelines are being used with this set-up?

So hopefully the question is clear enough:doah:
the failure ratings for your engine lift/cherry picker are not so much related to the ram. the 8 ton rating is ton's more that you really would need. the failure is mostly likely to occur in shearing of the load-supporting bolts - the ones that carries most load are probably the ones atatched to the ram.

look at your cherry picker's profile, and call the length of the boom as the "x" direction, and the height of the hoist as the "y" direction, VERY little load is translated in the "x" direction as is in the "y" direction. thus if you're lifting 2000 lbs at full extension of the boom, your 8 ton ram finds this VERY easy.

the other source of weakness in this set up is considering moment (a.k.a. "torque"). the square tube used to construct the boom likely can't support a huge amount of moment - thus the low rating. if you have 2Klbs on your boom at full extension, then the moment 5 feet away (i assume this would roughly put you at the pivot point) is 10K lb*ft. this is not a load that your ram sees (ofcourse, even if it did see a 10K lb load, it's an 8ton ram = 16k lbs.). this load is only manifested in the square tube of the boom. moment is a "bending force", so at max moment, your boom has to stand up to 5tons of bending force. ;)

clear as mud??
 
I came up with this as a possible fix your your shackle problem...

316n8zn.jpg


This would allow you to use a longer shackle without having the side to side flex issue of a taller shackle (As tou are going to have to use on long shackle to get the range out of those springs!). If you had a support beam that went from frame rail to frame rail, you could make support brackets closer to the center of the truck that would allow you to use a longer pivot for the upper pivot point, so side to side flex of the shackle would be basically eliminated. Let me know if my diagram does not make any sense (The blue is the welded pivot rod though the shackle, and the red is bushings). I figure it could be tapped on the inside end, and have a bolt with a big washer on it to keep it in place.
 
I am very surprised you had that much flex as well. That shouldn't ride as rough as I thought it would. I agree you could use a longer shackle, but with that much change in where the spring eye is - are you going to have issues with the pinion angle changing? I guess the Rocks help with the static angle, but it looks like the pinion would drop quite a bit with flex.

Also if you find that you have more than enough force from the ram, you could get an over pressure valve to limit pressure and bypass that part of the circuit. Just ideas.
 
I came up with this as a possible fix your your shackle problem...

316n8zn.jpg


This would allow you to use a longer shackle without having the side to side flex issue of a taller shackle (As tou are going to have to use on long shackle to get the range out of those springs!). If you had a support beam that went from frame rail to frame rail, you could make support brackets closer to the center of the truck that would allow you to use a longer pivot for the upper pivot point, so side to side flex of the shackle would be basically eliminated. Let me know if my diagram does not make any sense (The blue is the welded pivot rod though the shackle, and the red is bushings). I figure it could be tapped on the inside end, and have a bolt with a big washer on it to keep it in place.

I think I follow...So the blue bar would be welded to the shackle and the whole assembly would rotate in the bushings? A setup like this would allow the shackle to rotate 360 when not attached to the spring. Relieving the issue seen in this picture. The shackle would also need to be much longer.
008.jpg



I imagine I would need to use some heavy duty material though. A panhard bar would help with that side to side flex as well.

Thanks for the idea man, I'm interested in experimenting with it.
 
Also if you find that you have more than enough force from the ram, you could get an over pressure valve to limit pressure and bypass that part of the circuit. Just ideas.


I am glad to hear this! BKinzey was getting me worried. Thanks.
 
I think I follow...So the blue bar would be welded to the shackle and the whole assembly would rotate in the bushings? A setup like this would allow the shackle to rotate 360 when not attached to the spring. Relieving the issue seen in this picture. The shackle would also need to be much longer.
008.jpg



I imagine I would need to use some heavy duty material though. A panhard bar would help with that side to side flex as well.

Thanks for the idea man, I'm interested in experimenting with it.

You got what I was trying to relay exactly. I was hoping the diagram was clear!
 
I think he's onto something.... so it'd eliminate the problem of the shackle hitting the hanger here...

Eventually the spring would come up and hit the bolt/bushing but it'd give you a heck of a lot more travel especially if you used longer shackles...

008.jpg
 
The main point behind my plan was to allow the use of a much longer shackle without the negative of the side to side movement typically associated with longer shackles mounted in stock form. If the shackle flipped most of the way around, it would just stay there!
 
The main point behind my plan was to allow the use of a much longer shackle without the negative of the side to side movement typically associated with longer shackles mounted in stock form. If the shackle flipped most of the way around, it would just stay there!


Your drawing (image?) isn't visible in this thread???

Also, CH has also indicated that he's planning to use panhard bars F&R to deal with sideloading issues. In my opinion, he'll need those no matter how long (or short) the shackles wind up being.... :thinking:
 
:haha::bow::haha::bow::haha::bow:


Dude, this thread is as close to porn as my wife will allow in our house :D !!

Those flex pics are super awesome!!


Thanks for the updates and pics :waytogo: :cool: !!
 
Maybe you could use a sliding eye. Basically the rear eye will bolt into two slots running the length of the frame and are free to move front to back how ever long the slots are. No shackles flipping backwards or maxing out. Just a thought.

PaulC
 
Maybe you could use a sliding eye. Basically the rear eye will bolt into two slots running the length of the frame and are free to move front to back how ever long the slots are. No shackles flipping backwards or maxing out. Just a thought.

PaulC

That would be a VERY long eye and since this is a mud truck I can imagine that the bearings wouldn't last very long on the rollers. Otherwise it's not a terrible idea. :wink1:

I'd have to say a 10" shackle with good placement would be the simplest and easiest way to make this suspension work. The panhard should take care of the majority of side load stress off of them and they should provide adequate movement without maxing or flipping.

Just my $.02 though. :p:

You could also go with a 4 link and put a shackle at both ends of the springs. :D
 
I wouldn't put rollers in. I would put a steel sleave inside some slotted UHDP that was on both sides of the spring. Pretty durable stuff and cheap to replace if needed.

PaulC
 
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That would be a VERY long eye and since this is a mud truck I can imagine that the bearings wouldn't last very long on the rollers. Otherwise it's not a terrible idea. :wink1:
When I was at the indy 4x4 jamboree this september, I saw one of the mud race trucks was running a sliding eye setup :D
 
Ive spent the last couple weeks figuring out the TBI wiring harness and all that B.S.

I had built the motor a year ago and needed to hear it start. Needed to know the beast has a workin heart. After that Ima get back to the rear suspension.
 
ya i kinow what you mean. When do you think it;ll be drive able?
 

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