It's a cruiser. I have the original bezel!
3 feet of original frame:
Cowl and firewall... well... most of it:
Hood and bib:
Incontrovertible evidence of 40'tude:
I just whittled everything that got in the way.
link suspension opinions...
- Thread starter 1978fj40
- Start date
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It's a cruiser. I have the original bezel!
3 feet of original frame:
Cowl and firewall... well... most of it:
Hood and bib:
Incontrovertible evidence of 40'tude:
I just whittled everything that got in the way.
You don't miss a thing!
my gawd that thang is awesome
Eskimo
SILVER Star
Click the link in my sig if you want to see how I ended up doing Rockwells under my 40 and not have it be 8' tall...
The front admittedly could use more triangulation, but it's still fine to drive even at speed.
The front admittedly could use more triangulation, but it's still fine to drive even at speed.
I don't really have anything of value to add here. I'm still running leaf springs up front, but I like them, super simple. My rig is mild in comparasin, but I want it to be street usable, at times. I haven't done a linkage in the front YET because it is so hard to get right. Especially on an existing frame, with the engine drivetrain mounted. I have considered something similar to a j**p long arm kit in front. Not a triangulated 4-link, but seems a little easier to clear everything, and a way to put some coilovers up there. Maybe not the best for a huge cruiser on rockwells, though. There is just so many things to clearance, with the engine and all. I looked a Eskimo's build and it looks totally sick to me, I was very impressed.
Rockwells are soooo big up on top, there is alot going on there. Alot to clearance under your truck, add some coilovers and huge, travel, you have yourself something super complex to build. If your trying to do a triangulated 4-link the front your in for it. Its been proven it can be done though. I'm not wanting to offend, but you could be in over your head. I would keep it simple, maybe a 2-link variation with a panhard bar in front. I've never seen a "grader ball-trailer hitch"(dont know what its called) set up in front, thats maybe for good reason. But in the rear it would be a simple way to do it, better for big rigs, like this. What I am getting at is do you want to wheel that thing. Get it out in the rocks and mud, roll it over maybe, be wild and have fun with it. Or spend the rest of your life building it. But then cruiser fab is fun also, a real brain exercise. If I were you I'd throw it together as simple as possible. Then drive it into the ground. I really think that it can be done and work very well without the triangulated 4-link. It's not a formula 1 car, its an offroad beater. Having the full hydro cleans it up in front, helps with options. I always worried, if your engine dies out there, you have no steering. Makes it alot more interesting to save a broken rig, stuck out on the trail.
Rockwells are soooo big up on top, there is alot going on there. Alot to clearance under your truck, add some coilovers and huge, travel, you have yourself something super complex to build. If your trying to do a triangulated 4-link the front your in for it. Its been proven it can be done though. I'm not wanting to offend, but you could be in over your head. I would keep it simple, maybe a 2-link variation with a panhard bar in front. I've never seen a "grader ball-trailer hitch"(dont know what its called) set up in front, thats maybe for good reason. But in the rear it would be a simple way to do it, better for big rigs, like this. What I am getting at is do you want to wheel that thing. Get it out in the rocks and mud, roll it over maybe, be wild and have fun with it. Or spend the rest of your life building it. But then cruiser fab is fun also, a real brain exercise. If I were you I'd throw it together as simple as possible. Then drive it into the ground. I really think that it can be done and work very well without the triangulated 4-link. It's not a formula 1 car, its an offroad beater. Having the full hydro cleans it up in front, helps with options. I always worried, if your engine dies out there, you have no steering. Makes it alot more interesting to save a broken rig, stuck out on the trail.
- Thread starter
- #27
hey notaf-ingjeep, first off, no offense taken. i am quite sure that i am stepping in over my head a bit here, no surprise there. i have been researching a lot, and to get it *perfect* just isn't going to happen. however, i already have the heims, so i figure that i will give it a go, i will probably use some cheap pipe for mock up so when i screw up horribly it doesn't cost as much, then get the real stuff when the suspension is designed. i may end up doing something totally different, however, i would really prefer to try the triangulated 4 link first. i started this project a few years back, so i am having to re-research a lot...
i went with single triangulated (top links) when i did my rear and it's worked out real well for me.....rear steer doesn't seem to be an issue at the speeds that i travel, and my body roll is much less than my friends similar FJ40 with dual triangulation
Right on, I was bored yesterday and thought I would throw in my 2 cents. Sounds like you are well aware of what your in for. Based on what you said, sounds like your where I was. My 4-link worked out well, as long as your in for all the research, trial and error, it will go well. I have to be honest and say that my design wasn't totally my own. I got an opportunity to steal one that I knew would be great. It was at a Uroc competition in 2003, at the Rmr racetrack in Utah. First comp. ever on a man made course I think. This buggy was built on a full cruiser frame. It had a 2f, a cruiser front axle with birf eliminators of some kind, and a custom cruiser rear w/centered diff, on 35" tires. It was as close to an actual cruiser built comp. buggy I have ever seen. I watched it on the obstacles and was impressed, not that I knew any better back then. Looking back it wasn't super cool for me to sneak into the pit and steal his design right there. He was cool about it though, and very kind about helping me. It is real close to what woody has posted in the tech section for his 4-link build. Mine is a little different, I have more separation at the axle (uppers from lowers), with a couple of mounting positions. My links are 38.75" with the heims eye to eye. It seems to work great for me, I really haven't seen what it can do yet. I needed a better driveline, I will have that finished soon. I don't know how well that design would apply for you. You will be much taller, but I bet you could adapt it to work. Might be something to consider, I wont say it is a perfect design though. It fits the frame real well, and is pretty neutral(squat vs anti-squat). Dont remember my numbers exactly, I think my taller mounting position is around 90%.
- Thread starter
- #30
i appreciate all the info i have gotten here, the more i can get, the less i have to figure out on the "learning stage" of the build, i have been through that many times before on dune buggies, and such. you never get them right the first time, there is always something more than you anticipate, i have a v8 front mount dune buggy that for the first 2 years i owned it, i never kept it running for more than 15 minutes until i broke something else, but once i got past that it runs reliably. so, i know this is gonna be some trial and error, i am just glad to have a good place to find some info on what not to do, so i can try to fingure out what i need to do...
mace and bellydoc, I think you guys totally missed the point here, all that was said is that a 4 link isn't going to rotate and trash everything right away. If you take out one link, a link mount, or whatever on a 4 link of course it's not going to drive straight down the road.
However, you most likely will realize it's broke before every other suspension component is destroyed, in which case a couple triangulated ratchet straps will keep the axle in place and get you back to the trailer just fine. I guess it doesn't really matter since the OP already seems set on a 4 link, I just thought the point was missed by a mile.
We did not miss the point at all. Most of the time, when something fails, you are in a bad situation (heavy climb, bound up). And s***s gonna break when it lets loose. Very simple.
With all due respect, I get what you're saying, but I know something about the geometry of this linkage system that I think you don't.
Even if you were driving down the street when a bolt worked loose on one end of an upper link, you'd still probably break the yoke on the pinion end of the drive shaft when you accelerate. This is because the axle will FREELY drift to the side and "wrap" at the same time, instantly maxing out the U-joint angle and blowing out one of the yoke ears.
Basically, what I'm saying is that you wouldn't want to try to limp home on 3 out of 4 links... even if it meant coasting downhill on a straightaway the whole time.
The point YOU'RE missing is that the size of the forces involved in a moving vehicle, and that the fluidity with which the suspension moves under driving conditions is COMPLETELY unlike what happens when you put the rig up on jack stands and try to jink the axle around with your arms or your tools. If you played with a 4 link -minus 1 upper that was dangling from the underside of a rig on a lift, and you did NOT discover how the axle can swing side to side and wrap back and forth, then you missed it (probably for lack of exerting realistic sized forces), but it's still there.
Even if you were driving down the street when a bolt worked loose on one end of an upper link, you'd still probably break the yoke on the pinion end of the drive shaft when you accelerate. This is because the axle will FREELY drift to the side and "wrap" at the same time, instantly maxing out the U-joint angle and blowing out one of the yoke ears.
Basically, what I'm saying is that you wouldn't want to try to limp home on 3 out of 4 links... even if it meant coasting downhill on a straightaway the whole time.
The point YOU'RE missing is that the size of the forces involved in a moving vehicle, and that the fluidity with which the suspension moves under driving conditions is COMPLETELY unlike what happens when you put the rig up on jack stands and try to jink the axle around with your arms or your tools. If you played with a 4 link -minus 1 upper that was dangling from the underside of a rig on a lift, and you did NOT discover how the axle can swing side to side and wrap back and forth, then you missed it (probably for lack of exerting realistic sized forces), but it's still there.
with all due respect, i've seen lots of 4 links break an upper, and i've limped them all back to the trailer with some creative ratchet strapping, with a wishbone setup, the upper goes and you're done period. with a 4 link, unless your s*** is way underbuilt you should be fine.
i build competition rockcrawlers for a living, what suspensions do on paper and real life are different things. bellydoc i've followed your thread on pirate for quite awhile and think the amount of research that has gone into your build is great, i just disagree that one upper link breaking on a 4 link means you're going to face immediate destruction of everything like you do with a wishbone.
hijack off, i'll let you guys argue over what exerting realistic sized forces do on a piece of paper now
i build competition rockcrawlers for a living, what suspensions do on paper and real life are different things. bellydoc i've followed your thread on pirate for quite awhile and think the amount of research that has gone into your build is great, i just disagree that one upper link breaking on a 4 link means you're going to face immediate destruction of everything like you do with a wishbone.
hijack off, i'll let you guys argue over what exerting realistic sized forces do on a piece of paper now
Interesting... so what is it that you do with the ratchet strap? Do you triangulate against the tension, fore and aft?
go from ps axle tube to driver side bumper or rear of the chassis and vice versa. a suckdown winch helps too, and baby it back to the trailer. by no means will this be good to keep wheeling or cruising around for fun, but it's kept sway bars, airshocks, etc. in one piece in ways that a wishboneless wishbone wouldn't. a single upper link has always been enough to stop the rotational forces of the axle in the situations i've seen though.
edit: no mace, i'm not saying that, just stop when you notice somethings not right, and hopefully you can work your way out. maybe you guys disagree because unlike out west we can usually bypass to get off of a hard trail after something like that happens, i guess if you're in a canyon in the desert you could be slightly more screwed as the ratchet strap/babying method won't work very well if you're still needing to get over hard obstacles.
edit: no mace, i'm not saying that, just stop when you notice somethings not right, and hopefully you can work your way out. maybe you guys disagree because unlike out west we can usually bypass to get off of a hard trail after something like that happens, i guess if you're in a canyon in the desert you could be slightly more screwed as the ratchet strap/babying method won't work very well if you're still needing to get over hard obstacles.
I have 2 broken driveshafts from a 4 link failing (gotta love the angularity of a 1350).
Additionaly, if you do not build the 4 link mount (to the axle) good enough, It will snap off as well. Leaving a similar issue.
I have towed a bunch of desert trucks back to camp with an upper wishbone failure.
Again, build it properly and strong, and none of this matters.
And yeah, in the canyons out here, if you get stuck, you are not typicaly limping back to camp. You need to make the rig partialy whole again to continue. Onboard welders are nice
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So breakage or not, it sounds like you're doing a lot with the rigging to constrain the axle. The crossed ratchet straps you describe are pretty F'ing clever and I'm going to remember that! The effect is the same as a panhard bar. It seems like you've made the busted 4 link system into a three link PLUS an effective panhard bar.
Whether or not my concerns about instant catastrophe are exaggerated (I'm professionally paranoid, so I grant that it's probable), the fact that you're rigging to constrain the broken linkage system is the point I wanted to make. 3 of 4 links are not enough to limit the motion of the axle.
I've not seen a linked suspension fail. I *have* seen a leaf sprung suspension fail. The time between the axle coming free of the spring and the driveline failure was too short to measure.
Whether or not my concerns about instant catastrophe are exaggerated (I'm professionally paranoid, so I grant that it's probable), the fact that you're rigging to constrain the broken linkage system is the point I wanted to make. 3 of 4 links are not enough to limit the motion of the axle.
I've not seen a linked suspension fail. I *have* seen a leaf sprung suspension fail. The time between the axle coming free of the spring and the driveline failure was too short to measure.
I don't really want to join the debate here! I see both P.O.V.'s, so lets put it this way. "You never want to be in this position". My opinion is 4-link all the way, but regardless, build it tough. I've seen a link fail twice on the trail (4-link, suspensions). No fun, but strapping it can limp you home, if you do it carefully. You could destroy a lot even on a 4-link, but if the upper of the 3-link and it fails...... Your f-cked the second it happens, if not, your super lucky! That thing will flip (axle) and tear s*** up, in the blink of an eye! Major damage is possible with a a 4-link as well, but there is a much better chance of less damage. Both times I have seen it, no big deal. They both broke when the rig's hopped backwards on a ledge, and landed on it link. There were enough spectators to spot the problem and yell "stop". If the drivers had just kept on the throttle......... DESTRUCTION! That's what I have seen out there. I have to say both points are valid, Domba420 is right. A 4-link will be better in this respect, but not "fool proof"!
