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Another Revision.... even a bit closer to buildable in "real life"

3LinkFront.jpg



The last revision had great vertical link separation (13" at the axle) but the upper link was SO high that I don't think it would have ever worked without hitting the engine on compression.

This one pulls that dimension down a couple of inches and loses some separation (11" total)... so my link loads are climbing again (64,498 psi!!! :yikes:) that is going to take a SERIOUS bracket and gusseting to keep that from ripping my axle housing to pieces... (suggestions welcome.)

I also moved the axle-side upper mount forward of the axle centerline. It's actually set to "-3" in the calculator. I can't really see a disadvantage, and it's not clear to me if there is anything "magical" that happens if I cross over the axle centerline into negative "x-axis value" territory. :thinking:

Finally, the upper link mount at the frame end was really high and far back in the last design. It's still pretty high, but I was able to push it forward several inches. (You know the suspension is getting crazy when you need to build "power bulges" in the passenger side floorboard to provide clearance for the suspension links!!! :haha:





-G
 
replies in blue...

Heath,

That's assuming that I'm in 4WD under acceleration, correct? :dunno: It seems that there has to be applied torque in the axle to change from compression to tension...

Correct. And under braking everything is opposite, (including the rear). Bur remember, where the weight transfer is is where the most traction, and the most forces are.

Without power going to the front end, are the lower links under compression for both ends? (I'm trying to think in terms of the vehicle just sitting stationary on the ground, with gravity pulling down on it).

That depends. Sitting stationary will normally depend on your shock angle from vertical (front/back) how it pulls on the links (assuming coilovers/air shocks). However, since you have portals, and the front axle will have caster, the housing will want to rotate back slightly, causing a small tension force on the lower links. However, all this is negligable compared to the forces under braking or acceleration.

What about if I take it off a "sweet jump" (Napoleon Dynamite style :wink1:) and land on all fours basically flat onto the ground? That would be a fairly high G's event so it would be nice to know if the compressive link forces are going to be cancelled-out during an event like that.

Assuming no braking or throttle is applied, the forces are still many, and dynamic because of traction, wheel momentum, bumps, etc. Too many to calculate, but they will probably not cancel each other out most of the time. Not unless both ends of shocks were heavily angled toward the center of the vehicle front/back and assuming everything is flat and perfect, and that setup would be counterproductive. For the most part, you can count on the back lower links being under tension during acceleration, and the front lower links under tension during breaking. If no throttle or brake is applied, then the shear direction of the hits on the tires will overrule any twisting motion of the axle as far as link forces go. So either everything will be pushing back, or everything will be pushing forward. The forces will never cancel each other out because whenever they are acting in opposite directions they will most likely be magnitudes off in the amounts of force.

With all that said, I would just build the center crossmember plenty strong, and spread the load out on the frame interface, and not worry about it. Its pretty common and a many jeep suspensions share a center crossmember for the links.

-G

Have you considered putting the upper link on the drivers side? The ONLY reason I say that is because of clearance issues. The passenger side already has the driveshaft and the tcase and the starter all there, so there may be more room on the passenger side since you still have to put a header on both sides too.

Passenger side maybe better for pinion control, but I think that may be negligable if the link mounts are braced and the housing is trussed.
 
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Thanks Heath,

The only motivation for passenger side link is that the upper link can be built off the pumpkin itself. The hope is that it doesn't end up being an enormous tower structure, and will be easier to make strong enough for the loads.

I should probably buy a starter soon for mock-up....you've mentioned that a couple of times and it hasn't been something I've thought about much until now.

PS motor mount is going to be crazy looking... But if things work the way I'm expecting, the upper link will travel up between he framerail and engine block, splitting the available space almost perfectly. :thinking:

If I can get 5" of uptravel I'd be thrilled. I may have to add a secondary set of bumpstops up front since the struts will give me closer to 6" of "up" with their preferred stickout.

I've still got quite a few vacation days left, so I'm hoping to get some actual bracketry built and some links to cycle.


-G
 
I'd get one of the new gear reduction starters, they are smaller and lighter, and you need the room! Even one from the parts store off of a newer truck will work and is easy to find on a trip if needed.
 
I'd get one of the new gear reduction starters, they are smaller and lighter, and you need the room! Even one from the parts store off of a newer truck will work and is easy to find on a trip if needed.

Link?

Amazon or Summit could have it here in a hurry....hint, hint! :waytogo:


Off to buy 50 lbs of #9 lead shot for my new shotbag, and some black threaded pipe for a new ceiling-mounted hose reel that Santa didn't bring me.... (ordered it today for myself!). Also need refills on my welding tanks, so I'm doing that today also. Trying to anticipate any possible setbacks to progress and deal with them now.


-G
 
Maybe I'm just weird, but even though I'm in the garage today it doesn't feel like "progress"...

I asked for a hose reel for Christmas, and when Santa couldn't make it happen I ordered it for myself. :laugh: It's only a 50' setup but it's a LOT larger than I was expecting. In a tall shop it's not a issue, but with my low ceilings I'm going to need to get creative to tuck it up out of the way.

Last Christmas (2011) I got a nice air separator but I never installed it.... My current air "system" is nothing more than a Quincy compressor with about 25' of rubber hose attached directly to it. LOTS of condensation along with lots of air.... My plasma cutter has never worked at 100% because of the moisture, and I'm sure my air tools haven't been loving it either. :whistle:

Anyway, I finally reached the breaking point and decided to invest some time to get "real" air distribution and filtering installed....

So far I've gotten some 3/4" black pipe installed across the ceiling and angled so that any water in the lines will run back toward the compressor and drain valve. Lots of surface area to help cool the air before it reaches the dessicant, hopefully most of the water will just drain back harmlessly to the tank-area drain so I don't use up the dessicant too quickly.

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When I bought the compressor many years ago, I also bought a mechanical valve that would automatically purge tank moisture each time the compressor kicked on. I'm going to see about getting that installed today as well.

I know that ultimately this will make my "shop time" much more enjoyable, but it is incredibly frustrating to burn 8 hours today and not see any forward progress on the actual truck today. :doah:


-G
 
I organized and cleaned all day today.. but I did wash a years worth of dust off the K5 for tomorrow.. :deal:

shop time is needed... I actually "like" hangin in the dungeon these days now that it's clean and bright... :doah: :haha:
 
Hey Greg, you want to tilt your air line AWAY from the compressor and have a low point for any water/moisture to drain to with a petcock drain at the bottom. Having the air line tilted back towards your compressor will do you no good until you have the air turned off and all pressure out of the line before any water/moisture can drain back. Also I would not suggest using iron pipe as it will rust internally from the water/moisture, you should use 1/2" or 3/4" copper pipe instead.
 
2012.12.31 - UPDATE! - HAPPY NEW YEAR!!!

Couldn't let this year end without at least a little more shop time and a few more progress pics... :thumb:

Finished up the air system, including the dessicant filter and the new hose reel...

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The plasma cutter ran a lot better today without any traces of water in the air. Nice.

Next order of business was actual build progress, not just shop improvements... I built the upper link brackets that weld to the front pumpkin housing first.

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Then after double and triple-checking my numbers, I tacked them into position with the large EVO heim in place.

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Moved on to the frame-side upper link mount (you know, the one that goes in the passenger side footwell. :whistle:)

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About this time, it should be obvious to almost everyone that you can't put a link between those two heims. Time to modify the motor mount..... Substantially.

I cut the old mount apart and built a large "bridge" onto it to move the motor mount to the top surface of the framerail...

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It holds the weight pretty well, but I will add an additional backbone brace to the top side of it for extra strength. Hopefully this will provide the necessary bump travel for that upper link. :thinking:

Here's a final shot of the installed link from below

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...and from the passenger seat:

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Took Rene's advice and bought a pack of these cutoff wheels. Very nice upgrade.

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These last a lot longer than the Nortons that I've used forever. Thanks for the suggestion. :bow:

-G
 
These last a lot longer than the Nortons that I've used forever. Thanks for the suggestion. :bow:

Glad they work for you Greg. Nothing better than getting a bit more bang for the buck with your consumables! :waytogo:

That link isn't staying single shear right? :popcorn:
 
Glad they work for you Greg. Nothing better than getting a bit more bang for the buck with your consumables! :waytogo:

That link isn't staying single shear right? :popcorn:


I'm on my 2nd disc in the pack after a lot of cutting today. The only reason I had to swap the disc at all is because the grinder fell off the workbench and flattened one side of the disc. :whistle: They wear like iron, and cut really smooth.... I'm a believer.

Yeah, don't take anything you see too literally. I'm "trying" to only build mock-up bracketry (only good enough to test clearance and suspension travel).... It's been a real test of my OCD not to build the bracketry as nice as I know how. The pumpkin brackets are pretty well executed, but the frame side bracket is a simple placeholder until I know that everything works correctly.

Truth be told, the frame side bracket is actually 3/4" too low anyway, so I need to rework the bracket under that thick sleeve to raise it up a bit.

Once I get some lower links installed (and a track bar!) I'll move things around and see what sort of travel I can actually get. :waytogo:

-G
 
Greg when I build mock up brackets I tend to try to make them bigger than I think I will ever make the brackets, bigger everywhere, I will even use huge washers in places it tends to give you a better idea of where everything is going to hit or miss in a bad situation, and it can allow you to shape a bracket differently to prevent hitting in a bad situation.

Of course I am constantly getting bad situations so :D
 
Some off the wall crazy stuff that you're running into, Greg. Looks like a lot of back and forth on where and what will fit.

The headers are really going to be something of a custom nature now. Curious on what path you're going to go on that one.

Have you thought about changing in a couple of those gas bottles for a bigger one? It sure is nice having twice the weld time, without taking up any more space really.
 
Link?

Amazon or Summit could have it here in a hurry....hint, hint! :waytogo:

-G

Well, I was thinking you coould get it from Advance or O'Reilly, off of a newer truck, but if you want to order it they look just like this...

http://www.summitracing.com/parts/pro-66268/overview/make/chevrolet

Then you could easily find an exact replacement if needed.

Or if you want a high end one a Tilton, CSR or other mini starter could be ordered, but it may be even smaller and a replacement would be harder to find if clearance was an issue. Although if clearance is needed it would work well.

http://www.summitracing.com/parts/til-54-10001/overview/make/chevrolet


http://www.summitracing.com/parts/csi-100sbp/overview/make/chevrolet
 
Beware of the aftermarket mini starters. They generally don't support the gear on both sides, only the starter side. I've heard bad things about their longevity vs the factory style like the first one linked above.
 
As usual your stuff is so pimp as to be depressing for the rest of us :haha:

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The Legacy stuff, though -- that's "Flexzilla", right? -- is the shiztnit though. Somebody here turned me onto it, and it is AMAZING airhose. Doesn't have a shape memory, can turn in ridiculous tight bends without kinking like the thick stuff ... love it.

And that neon lizard green color makes it easy to locate. With your eyes closed. :D

-- A
 

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