[lake_harley]

I'll be building a triangulated 4-bar for the '33 Willys I'm just starting on. I did one on my T roadster a couple years ago and am really happy with how it worked out.


Since the Willys is bigger and heavier than the T, I am a bit undecided about what size tubing and threaded ends to use for the bars. I already have poly bushings with metal inserts for 5/8" bolts but have considered building the threaded ends with 3/4" male threaded bolts welded to the tubes that have the bushings in them. I have a good stock of 1" X .156" DOM tube that is the proper size to tap for 3/4" threads. I'm debating whether I should just use the 1" X .156" for the bars, or just use threaded "slugs" of that tube to weld into 1 1/4" X .120" wall for the tubes themselves. FWIW, only one end will have threaded ends. The other end, likely the front, will have the tubes welded directly to the poly bushing's tube.


The HP of the car isn't going to be any 600 HP ground shaker so I think the 1" X .156" would hold up, but I wonder if it's going to look "spindly" under the car? So....I'm looking for feedback of what other folks have for tubes on their triangulated 4-bar suspension. Please indicate too what kind of car it is so I have some comparison of scale.


Thanks, in advance.


Lynn

[techinspector1]

If I ever have to do it again, I'll use 3/4" Johnny Joints from Currie......
https://www.currieenterprises.com/CE-9112N75L-15

[lake_harley]

Thanks for your reply and the link. What did you use before for the threaded ends? Also curious what tube diameter and wall thickness you had/have, and what kind of car & HP?

[ericnova72]

My 2500 lb Vega has 1" x .156" wall direct threaded links, 3/4"-16 threads, and 3/4" chromoly Rod ends(hiems joints).
That's a parallel fully adjustable drag race 4-link though, with a panhard locator....and I'm not even slightly worried about throwing 800HP at it.

Look at how flimsy OEM stamped arms are in factory 4-link cars. Not hard to be stronger with almost any kind of tube replacement.

We also did a drag race 4-link in a Pro-Street '84 Monte SS, from a Competition Engineering kit. That was 1-1/4" x .083" wall 4130 chromoly tube with welded inserts, also for 3/4" hiems. More than 10 years ago and nothing has broken, 650HP Dart Little M 406 SBC.

In terms of weight a Willy's is considered pretty darn light still, I can't believe it would be over 3000 lbs even with a big block in it.
Is it Model 77(1933-36 body style) or the later '39-41 style??

[techinspector1]

Originally Posted by lake_harley

Thanks for your reply and the link. What did you use before for the threaded ends? Also curious what tube diameter and wall thickness you had/have, and what kind of car & HP?

HMMMM, that was 35 years ago, so you are testing my memory. What I remember most is the harsh ride with 3/4" Heims, metal on metal. I do remember that I angled the tubing down a little on the bottom and a lot on the top, to put the Instant Center at just a few feet in front of the front bumper. First pass at the drag strip, truck went 103 mph, high 12's on a stock converter. None of my son's buddies had a rig that would go a hundred miles and hour at the drag strip.

https://www.dragstuff.com/techarticl...inktuning.html

The vehicle was a '72 Chevy Luv pickup. 455 Olds, TH400 and narrowed '57-'64 Olds 10 1/4" diff with 3.90 gearset. It was just a run-around rig for my son to drive, a mild build with W30 hydraulic cam, two AFB's on an Offenhauser intake, log exhaust manifolds......absolutely no room for headers.......maybe 325-350 hp. The WOW factor was popping the hood in front of a bunch of high school freshmen. We recessed the firewall and installed an 8.50 cage. Imagine touring through the Sonic Drive-in with the window net up? HAHAHAHAHAHAHA. And by the way, the only way I can remember all this is that I have it in a scrapbook.

[lake_harley]

ericnova72 and techinspector1.....Thanks for the additional input. One thought I had about using the larger 1 1/4" tube with the threaded inserts is that they would be just a tiny bit easier to build. The 1 1/4" tube could be cut with plenty length and with everything mocked in place the final length cut to accommodate the threaded bungs and rod ends. Kind of a lazy man's way to do it I suppose but I am rather lazy.


The Willys is a '33 but it is a "stretch" fiberglass body that will end up at about 108" wheelbase. I think a stock '33 is 100", and I wish that's what it was, but the additional length will probably add stability and a better ride on the street.


Lynn

[kso]

Thought from here: Yes 1" tubing whether-or-not it could do the job just looks too small, going up to 1 1/4 (.120 wall) makes a big difference, what I used in the purple Challenger and our off-roader Cherokee. Sleeving w/ the 1" for threading then makes sense, or you can buy ends with a nice shape already threaded from an off-road supply. Do a couple (or more) plug welds along with welding at the end and weld like your life depends on it, not like a guy I know who thinks his bird doo-doo mig splatter is good enough 'cause it hasn't broken yet. Solid rod ends are harsh but you won't have to worry about wheel hop which can be a problem with bushings incl. urethane with big tires and more power.

[lake_harley]

Yesterday I committed to a plan and that was to go ahead with 1 1/4" tubes with threaded fittings weled in. Yes, I will plug weld them since they'll insert about 1.5" into the larger tube, as well as welding at the tube/fitting joint . I started machining parts yesterday to do my own poly-bushed rod ends. Since the car is intended for the street I thought the poly bushings would hold up better over time than spherical rod ends, and not need regular cleaning and maintenance.


I'll try to post up a couple photos in the next day or two of the components. Just when I'll get started actually building it in the car with the way life works is anybody's guess.


Lynn

[lake_harley]

I'm new to posting here and was looking for a place to edit my post. I re-read my last post, after it was posted, and realized I made a spelling error and I'm just sort of nuts in that I try to spell and use punctuation as well as I can. But, I have looked all over and didn't see how I could do a edit or correction.


Thanks


Lynn

[techinspector1]

You have exactly 30 minutes after you post to change your post. At one second after 30 minutes, it's carved in stone.