Got what I think might be a new question

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Ol'fogasaurus
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Re: Got what I think might be a new question

Post by Ol'fogasaurus » Tue Sep 13, 2016 7:06 pm

Thanks Marc, the pix helped to make sense of what is going on. The second page came in upside down but as part of my job I had to be able to both read and write not only upside down but backwards also.

I've learned a lot of what is available out there on the string. I hope it might help others also.

Lee

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Re: Got what I think might be a new question

Post by GS guy » Wed Sep 14, 2016 7:37 pm

Why not replace the through rod with an internal sway bar? SOP for Formula Vee/Formula First. Straight through bars leave some questions - since now the trailing arms are free to rotate independently and center grub screw is now out of the picture. What provides the rod to t-arm bearing surface, just the end cap to rod nut (and grease between the two)? What about T-arm end-play to the beam, just the beam rubber seals?
F-Vee uses solid aluminum or steel bushings in place of the seals, then uses the sway bar to set the end play for the T-arms. Gets rid of the external sway bar and provides a solid mounting for the T-arms.
Use a SAW adjuster in the other tube with stiffer SAW springs to set ride height and stiffness. Should be about the ultimate for trailing arm front suspension set-up for a lighter weight buggy.

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Re: Got what I think might be a new question

Post by Marc » Wed Sep 14, 2016 8:02 pm

Many years ago I built a beam for a circletrack car that only had functional lower springs (it also used Carrera coil-overs, ~105lbs/in) to carry the weight and allow for easy weight jacking. Used the stock upper spring stack as an integral swaybar à la Type III (requires removal of the center anchor block in the upper tube).

Where a Type III has an endplay adjustment and thrust pieces, this setup did not. I simply opened up the I.D. of several crankshaft oil slinger washers so they'd fit between the control arms and the upper tube. Used the stock upper seals with the outer lips shaved off as thrust pieces, and kept it well-greased, checking for excess endplay regularly. It was a little crude, but quite effective.

Since we needed camber for left turns only, the RH side got a single washer and the LH side got a few...but you could make it an even split if you wanted "normal" camber.

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Re: Got what I think might be a new question

Post by Ol'fogasaurus » Wed Sep 14, 2016 8:32 pm

GS guy wrote:Why not replace the through rod with an internal sway bar? SOP for Formula Vee/Formula First. Straight through bars leave some questions - since now the trailing arms are free to rotate independently and center grub screw is now out of the picture. What provides the rod to t-arm bearing surface, just the end cap to rod nut (and grease between the two)? What about T-arm end-play to the beam, just the beam rubber seals?
F-Vee uses solid aluminum or steel bushings in place of the seals, then uses the sway bar to set the end play for the T-arms. Gets rid of the external sway bar and provides a solid mounting for the T-arms.
Use a SAW adjuster in the other tube with stiffer SAW springs to set ride height and stiffness. Should be about the ultimate for trailing arm front suspension set-up for a lighter weight buggy.
I had to read this several times before I fully comprehended it as I was shocked! (shouldn't have because it sounds so simple) This "internal sway bar" something else I have never heard of before. The rest sounds more or less what I was talking about even before I found out about the SAW spring stack replacement leaves for the bottom torsion bar for a BJ beam.

Most of the stuff I have heard about for softening up the beams has been doing it the hard way. It sounds like this fix has existed for quite a while but has pretty much been located within the racing community so it hasn't gotten out (or stumbled into) to others who also could benefit from it.

I thought this string was through but surprise, surprise... there always seems to be something else.

Is this good for BJ or just K&L? Is it SAW also? Got a part number for the internal sway bar so I can look at it?

After all the stuff that has come out on this string I think I need to change the title of this string.

Thanks for the inputs everyone as I am sure there are going to be a bunch of people who can use the info.

Lee

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Re: Got what I think might be a new question

Post by Marc » Thu Sep 15, 2016 11:30 am

The beam I built the way I described above was BJ. At that time the rules allowed the addition of coil-overs but required that the stock springing method remain intact (modifications such as adjusters or cut-n-turning were allowed). I was pushing the envelope a little since technically the top tube no longer had anything to do with supporting the car, but since it still had the stock springs inside (demonstrable on demand by removing a control arm) I got away with it.

The usual way of doing a through-rod has it poking out the ends of the control arms, a dead giveaway that there's no stock spring inside...and unless you're after significant negative camber on both sides you still need to add some sort of spacers between the arms and the ends of the tube.

One competitor did a clever variation - which wasn't detected until years later when the car was brought out of the weeds to compete again, but by that time the rules had been slackened so it was moot.

They machined blocks with internal threads to screw over the ends of the through-rod which had grub screw detents so the control arms could be attached. Another such block located at the center secured the rod from moving laterally, and everything looked completely stock from the outside. No need for any thrust control system that way - the control arms moved in & out slightly on the threads as the suspension traveled, but it was minimal over ~3" of travel and since both upper & lower shifted by the same amount there was no net camber change.

If one were to use this method on just the upper tube, camber change could be a concern. One solution I can envision to reduce that would be a bearing at the center which would allow the rod to rotate without lateral movement.
Last edited by Marc on Thu Sep 15, 2016 11:37 am, edited 2 times in total.

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Re: Got what I think might be a new question

Post by Ol'fogasaurus » Thu Sep 15, 2016 11:36 am

Marc wrote:Many years ago I built a beam for a circletrack car that only had functional lower springs (it also used Carrera coil-overs, ~105lbs/in) to carry the weight and allow for easy weight jacking. Used the stock upper spring stack as an integral swaybar à la Type III (requires removal of the center anchor block in the upper tube).

Where a Type III has an endplay adjustment and thrust pieces, this setup did not. I simply opened up the I.D. of several crankshaft oil slinger washers so they'd fit between the control arms and the upper tube. Used the stock upper seals with the outer lips shaved off as thrust pieces, and kept it well-greased, checking for excess endplay regularly. It was a little crude, but quite effective.

Since we needed camber for left turns only, the RH side got a single washer and the LH side got a few...but you could make it an even split if you wanted "normal" camber.
Thanks Marc. I think I got so excited about the internal sway bar that I missed this completely. Since I have never knowingly played with Type III stuff (other than the steering box I now have :roll: ) I am not completely sure about what you said.

Image

Am I correct that you have to cut the center section out:

Image

Drill out the center piece, weld the section’s adjuster hole up to keep the sand out (I don’t think putting the locking bit back in would be a good idea as it could work its way back out) and weld the tube piece back in place?

The removing the seals and shimming it out I think is the big problem. The end seals are important on the sand or at least I think so. I understand the reason for the shimming bit; otherwise the upper arms could slide/float back and forth in the beam more than one would want.

With sand flying everywhere, witches holes to drop into, places that are soft where others have got stuck into and the sand hasn’t filled the hole in a packed manner yet, getting high centered in the transition between a dune and the flat area, “no-see-ums” plus so many other ways to get the front of the car sanded I think those beam end seals are a necessity.

I gotta think more about this as an option. Thanks again for the imput Marc.

Lee

I didn't see the update until I did this. I will take some time to read and understand it but for now...

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Re: Got what I think might be a new question

Post by Marc » Thu Sep 15, 2016 11:46 am

Ol'fogasaurus wrote:..Am I correct that you have to cut the center section out...Drill out the center piece, weld the section’s adjuster hole up to keep the sand out (I don’t think putting the locking bit back in would be a good idea as it could work its way back out) and weld the tube piece back in place?...
That's what I did - although I did use a dummy shortened grub screw to maintain a stock outward appearance ;)
Initially the proof-of-concept prototype was done by simply grinding the spring stack to a round shape at the center, but I was concerned that the leaves might eventually break and leave the upper arms free to float out.

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Re: Got what I think might be a new question

Post by Ol'fogasaurus » Thu Sep 15, 2016 12:51 pm

GS guy wrote:Why not replace the through rod with an internal sway bar? SOP for Formula Vee/Formula First. Straight through bars leave some questions - since now the trailing arms are free to rotate independently and center grub screw is now out of the picture. What provides the rod to t-arm bearing surface, just the end cap to rod nut (and grease between the two)? What about T-arm end-play to the beam, just the beam rubber seals?
F-Vee uses solid aluminum or steel bushings in place of the seals, then uses the sway bar to set the end play for the T-arms. Gets rid of the external sway bar and provides a solid mounting for the T-arms.
Use a SAW adjuster in the other tube with stiffer SAW springs to set ride height and stiffness. Should be about the ultimate for trailing arm front suspension set-up for a lighter weight buggy.
After reading Marc's input yours now makes more sense to me. I am still concerned about sand intrusion so that is something I will have to look into.

Thanks again. Lee

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Re: Got what I think might be a new question

Post by GS guy » Thu Sep 15, 2016 4:03 pm

The F-Vee and Formula First supply chain is a cottage industry, with very limited suppliers and not all that generally known about from what I gather. F-Vee uses LP hardware, F-First moved up to BJ beams. They get pretty radical with some of these setups, inboard shocks, rack & pinion steering, etc. Neat stuff! I think that it veers so far from the more "well know" standard beam and of road modification treatments that not to many people seem to know about it?
I googled a couple of links to check out:
https://campbellmotorsport.sharepoint.c ... acers.aspx
http://www.sracing.com/Store/FV_Stuff/FV_Stuff.htm
Note: I don't think SR Racing still sells these parts, but you could contact them and see what's current.

I forgot about your intended sand use Ol'fogasaurus - so not too sure how applicable these parts are. From what I understand, their are no "seals" on the sway bar equipped beam and regular greasing keeps the metal to metal wear on the seal replacement bushings minimal - but that's on a road course!
I've though you might be able to modify the metal spacers to utilize a nice O-ring to seal against the trailing arm? It would be better than nothing, but not sure how well it would do out in the sand.

Airkewled also makes a through-rod beam set-up for their air-ride kit. Maybe they have something a little better that just a rod with threads on the end? I'd think some kind of bushing/bearing between t-arm and rod would be in order, plus some kind of sealing arrangement. Still not sure how you handle the side to side thrust without some kind of bushing replacing the beam end seals. The threaded t-arm anchors Marc discussed is an innovative idea! Like Marc stated, I too was kind of envisioning some kind of bearing system at the center of the beam, anchored to the through rod/sway bar - with center free to rotate while still providing a thrust anchor for the trailing arms.

Of course - there are some pretty slick A-arms systems available that do away with all the beam shananagins! :D
Jeff

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Re: Got what I think might be a new question

Post by Marc » Thu Sep 15, 2016 5:35 pm

I have to wonder whether you'd really want a front anti-swaybar in the sand, though. Do you need to promote understeer? The ASB also resists articulation on uneven terrain (dunno how much of that you encounter in the dunes, but it's one reason you seldom see one on an off-road rig).

Have you already tried running both upper & lower springs with just the 12 narrow leaves removed? You can even take out some of the wide ones provided you retain a short section at the middle & ends for the grubscrews to seat properly into...they can just be held in place with a little tape during assembly, once the grubscrews are seated they're not going anywhere.

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Re: Got what I think might be a new question

Post by Ol'fogasaurus » Thu Sep 15, 2016 6:25 pm

With what I had in mind the sway bar bit wouldn't be that much... I think. I had a long talk this afternoon with Doug at Autovice. He suggested some things (I had written a long bit but my computer went down and I lost it) but the most important fact he brought up is when you remove the center pinning section of the beam you turn the spring pack from two spring packs into one long one which probably reduces the effect of the torsion bar/spring pack but by just how much; I believe that to be true.

That being said: No, I really don't want to run a sway bar on the sand but if it is not working that much I think the hang and compression won't be affected that much but good, properly valved shocks will be very much more important but that is expected out on the dunes. BJ beams, as I understand it usually can be made to handle an easy 6" of travel and with work maybe close to 10" but I am not going there.

I don't really want to go with Coil overs on good, properly valved shocks (not the overload coil-over shocks that are easily found. Nor will I run the air-fill shocks that came with my blue buggy when I bought it... again. Almost went ass-over-tea-kettle with those dangerous little jobbies).

Weight on the front of the car was also talked about. He has a mid-engine rail so between he and the engine being in front of the wheels the weight on is beam is much more than I will have. When I was younger I could lift the front of my buggy off the ground.

I don't want to cut or nick the springs so that they break the first time you put weight on the front suspension. There are some big drawbacks to that in my opinion such as: how many leafs do you neuter.

If I put the torsion bar on top of the beam. when using through roads, rather than leaving it on the bottom would it hit the shock tower? Dono!

If I leave it on the bottom the upper torsion tube becomes completely neutered and really adds nothing to the suspension other than holding the top of the spindle in place.

You were able to race with that setup your driving on the track has to be much more aggressive than my "Ol' Fart cruising" even with the occasional Aw $#it! GS guy is probably running a much lighter rig than even mine are but again, he is pushing things harder.

And yes, the sand is hard on things but so fun!

Is this getting too complicated? No, not in my opinion as facts are coming out so it is worth it.

I meant for this string to find and pass on information which may not have been out there; which I think it has. It sure got me thinking differently anyway.

As Doug at Autovice once said: most people don't think that far ahead. :twisted:

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