VariSchock tower....Help

[tmcmillan5]

I had this over at Chevelle Tech but got limited responce so I thought I'd be better off posting over here.

The car is a 68 Chevelle Conv. and getting an all Aluminum LS swap.

Thanks, Tony

http://www.chevelles.com/forums/showthread.php?t=347203

[dhutton]

If I was going to try something like that I would go with an SPC lower control arm to lower the coilover mount and then I would take a look at the Chicane coilover mount from ATS/Speedtech to see if it could be adapted to fit.

Edit: I'd also buy a copy of Makr Savitske's new book and read it cover to cover at least twice....

[NickChassisworks]

This looks like a 5.15" or 6.15" travel shock which would require a 12" long spring. Getting springs in that length with a high enough rate to support the front suspension might be the next challenge. Look at a circle track spring maybe. We have a coil-over conversion shock build to work with the stock body mount, although with a stock LCA length of this shock can again become an issue.

https://static1.pt-content.com/images/noimg.gif

https://access.cachassisworks.com/prod_info/Instructions_CAC/899-031-209.pdf

I do agree with the comment above, make it strong, very strong.

[JRouche]

I had this over at Chevelle Tech but got limited responce so I thought I'd be better off posting over here.

The car is a 68 Chevelle Conv. and getting an all Aluminum LS swap.

Thanks, Tony

http://www.chevelles.com/forums/showthread.php?t=347203




I need to fab-up an upper adjustable Coilover " tower" but I need some help from you guys to let me know if my mockup is close with regards to alignment. I want to weld-up a vertical piece of channel for mounting and fab-up a smaller piece of channel to attach to the eye of the shock which would slid up & down the frame channel for adjustability.

My concern is in keeping all my pivot points as bind free as possible so my vertical placement of the frame channel is critical. The pictures below are with everything in place with hand tightened bolts. The frame is level. The coilover is for the rear of the car and used for mockup only, its a 12" spring extended 16" eye to eye. My front coilover will be a 9" spring 14" eye to eye I believe. SPC uppers have 6" adjusters at present.

Take a look and let me know how my " Alignment " looks as well as my lower
A-Arm for potential ride height.

Thanks, Tony

Ok, so Ill try to help...

Im not sure what you are trying to show with the pics. I dont see the frame mounts in place. It looks like you are showing the fore and aft displacement of the coil over right? Lemme talk about the frame mounts first.

A vertical channel butt welded to the top of the frame might not be enough support. There really is alot of force on the upper mounts, I think the channel should be welded at least 3" along its length to the frame (inside, outside or right down the center of the frame with the channel notched). If the wall thickness of the channel is sufficient (3/16" min) then that part will hold up.

And an option to having three inches of contact area on the frame would be to use gussets with the butt welded upright channel. Id use two smaller gussets on each side VS one large gusset on each side.

Now the vertical mounts are solid. How to make them so the upper eye wont bind? And if I understand you, you want to have an additional channel that fits into the main channel and the secondary channel is what the upper eye is attached to?

Personally I think thats over complicated. You can make the main channel large enough on the inside dimension and use spacers between the eye and the channel.

The nice thing about spacers is you dont have to get very critical with the angle of the main channel. Take a degree measurement of how far back the coil over tilts and trim the channel for that degree. The back leg of the channel will be shorter.

So once you get the main channel welded in, with the suspension "neutral" it will be very close. And if you allow for at least a 1/2" spacer on each side of the eye when its in the channel you can easily change the spacers (less up front, more to the rear, or reversed) to allow for the top eyes movement during alignment (caster) changes.

But I would start off by removing the springs, you dont want or need them in place for setting it up, they are just a problem.

Remove the springs, set the lower control arm to the correct ride height (it looks low, it should be level) with a jack to keep it in place. Then set the upper eye to the ride height that the coil over will be at with the weight on the car.

And thats solely a function of the shock travel. And if the shocks you picked out dont fit the requirements then its time to change the shocks. You cant over drive the shocks, they will fail.

So you find out what the manufacture's recommended travel (sweet spot) for the shock is and thats your starting point. Put the shock at that length and use whatever, I like cheap twine and set the shock at that dimension.

Then you know where to put the main channel. You didnt talk about the bottom mount for the coilover much so I assume its where it needs to be. Bolt it in tight so there isnt any slack and the top eye will automatically show you where it needs to be without any bind. The top eye will be at the proper distance from the lower mount (cause you tied it off) at ride height and the angle will be right there.

If the bottom eye is firmly bolted in place it will show you the angle, remember to have the lower control arm at ride height (usually level with the ground).

Now the upper eye is in its position, look at the angle of the shock. That angle needs to be copied to the frame mounted channel. And really, it can be eye balled. Get the eye in the center of the one inch too wide channel after you copied the angle (the back part of the channel will be shorter) and it will be centered for all of the travel of the coil over (shock). I like to use measuring rulers.

Copy this angle.

https://static1.pt-content.com/images/pt/2011/03/coiloverlean-1.jpg


So why the spacers? To allow for welding issues is good. To allow for caster changes (alignment adjustments), is also good.

I like to have some wiggle room between the hard welded parts and the removable parts. If you change the caster (during alignment changes) much it will want to move the top of the shock. So some shims for the top are handy. I use shims for mocking up and turn (the lathe) a solid aluminum spacer for the final part. But REALLY!! Shims and washers will work just as well. Its really nice to have some built in wiggle room when the time comes to assembling it all up.

Ok, last but really not least. The fasteners. My "coilovers" came with two bushings. One had a 1/2" ID for 1/2" bolts and the other bushing was for 5/8" bolts.

1/2" quality bolts are prolly plenty good enough. But dont forget. Its not just a shock. Its the entire weight of the car, they are coilovers. So I went with the 5/8" bolts and bushings. JR

[tmcmillan5]

Thanks for the reply J. Yes my pictures were to used to show my rough alignments for comments ?. My space is kinda tight with this style upper arm but I like the adjustability & the Bling factor. I've made more progress w/ the upper mounts as shown in these new pictures.
What I don't understand in your posts is what affects Caster changes will have other than clearance of the spring Fore & Aft, the shock will remain stationary based on placement at the Lower Arm, correct?.
My Sq. tube Main support is in place in alignment with shock travel, the lower mount runs parallel with the lower control arm bushings so movement is consistant thoughout shock travel. The upper mount bracket will slide into the main support and will be bolted in for testing prior to final placement when it will be welded in solid. I will support & gusset as creatively as possible and replace cut-away frame for a clean look.

So you suggest I raise my lower arm a bit ? presently it is 24.5" from floor as well is the frame level and 24.5" at the side Main channels Fore & aft.

Thanks again, Tony



https://static1.pt-content.com/images/pt/2011/03/DSCF2656-1.jpg

https://static1.pt-content.com/images/pt/2011/03/DSCF2652-1.jpghttps://static1.pt-content.com/images/noimg.gif

[JRouche]

Hey Tony. Ok, I see what you are doing now. You said channel but its actually tube. Pics ARE worth a 1000 words, or more.

I may have gone off the reservation with my caster talk. Disregard ALL of that. Drunk talk is all :screwy:

As far as the lower arm. Might just be the pics but it looks like its pointing down some. Place a digital or bubble level on the arm. If the frame is level (side to side) the arms should show level. And personally I like a just slightly up hill setting (ball joint side higher) if its possible. And I mean just a 1/4" really.

Its looking good. I think you have a handle on the sitch. JR

[JRouche]

Hey Tony. Ok, I see what you are doing now. You said channel but its actually tube. Pics ARE worth a 1000 words, or more.

I may have gone off the reservation with my caster talk. Disregard ALL of that. Drunk talk is all :screwy:

As far as the lower arm. Might just be the pics but it looks like its pointing down some. Place a digital or bubble level on the arm. If the frame is level (side to side) the arms should show level. And personally I like a just slightly up hill setting (ball joint side higher) if its possible. And I mean just a 1/4" really.

Its looking good. I think you have a handle on the sitch. JR

Oh, if you wanted to know where my drunk mind was going. By caster changes I meant when you change the caster during alignments. Say you wanted to use some heavy caster numbers. Im not sure how much the lower shock mount will move. But I was thinking if it moves to the rear (or front) by say a 1/2" then that will put some tension on the shock shaft and bushings. So I was thinking if you had spacers on the top mount you could move the top mount by a 1/2" (or whatever amount released the bind). Not sure where I got that thought from. Prolly out of a beer can is my best guess. :)

[tmcmillan5]

J thanks for your input regarding shock only mockup. I took a spring off and placed the 5.15" travel shock in at 2.26" compressed (40 %) which gave me a starting point to location my top mount. I clad my upper mounts in 1/8" flat stock for added strength and cut them down in size to give me a more balanced space between the upper arm. The new heighth of the shock tower looks workable to me now with a 12" spring @ a 16" extended coilover from eye to eye. I also raised my lower arm an additional 1" not level but close.

https://static1.pt-content.com/images/pt/2011/03/DSCF2681-1.jpg

https://static1.pt-content.com/images/pt/2011/03/DSCF2679-1.jpg


https://static1.pt-content.com/images/pt/2011/03/DSCF2678-1.jpg

https://static1.pt-content.com/images/pt/2011/03/DSCF2676-1.jpg

https://static1.pt-content.com/images/pt/2011/03/DSCF2672-1.jpg

[JRouche]

J thanks for your input regarding shock only mockup. I took a spring off and placed the 5.15" travel shock in at 2.26" compressed (40 %) which gave me a starting point to location my top mount. I clad my upper mounts in 1/8" flat stock for added strength and cut them down in size to give me a more balanced space between the upper arm. The new heighth of the shock tower looks workable to me now with a 12" spring @ a 16" extended coilover from eye to eye. I also raised my lower arm an additional 1" not level but close.

Looking good... Two points.

One, the shocks are up side down? Are they good to go like that? Just curious.

Next is the tube wall thickness thats below the part that you thickened up with the "cladding" of 1/8" plate. Its gonna be a stress point. The tube that looks to slide into the frame welded tube. It looks to be 1/8" wall tube (maybe 3/16").

Ideally the entire section would have been 1/4" wall bent to the shape. And yes, 1/4" wall tube that small is some pretty beafy stuff. But its not gonna flex or bend. And you keep from making the joint.

Its the joint really that bothers me. Where the claded section ends and the thinner tube starts. That joint can be a point of shear stress. One way to help it is after you get ALL of you measurements done and are ready to final weld it is to make some heavy bevels on the cladded section and the frame mounted "receiver tube" so when you do the final welding the inner tube (hopefully its at least 3/16" wall) will be completely welded into both structures.

The heavy beveling will make it possible to weld the thicker outer tubes to the inner tube and get a complete joint.

And I mean using some HEAVY heat. It will be more heat than the inner thin tube can handle. You should get some over welding, where the inner tube has been penetrated and if you could see inside of the tube you will see some filler or "sag" where it was so hot that the entire joint (all three sections) are melted into one. And for that weld, if you are MIG welding it I would reduce the wire feed and crank the heat up to max is its a 250-300amp box.

Nice 45* bevels on the upper and lower sections so at the root you can just see the inner tube and put alot of heat right at the root. The slow wire feed will make it a nice flat bead. Even with a large welder and high currents and wire feed it will still blow out the thinner walled tube before the two outer sections get hot enough.

So use a slow wire feed, with as much current as the feed can handle to completely heat up the entire joint. You want to melt as much of the upper and lower parts of the joint as possible.

The idea is not about stuffing in as much filler as you can. Its about putting as much heat in there as you can while still keeping the filler solid once it leaves the tip. And yes, that means some close welding. The stick out might be only an 1/8". Heavy heat, small amount of filler. Thats welding HOT!!. And I think thats what that joint needs. Actually, thats how I like to do most of my welding. Heavy heat and little filler.

Now? The next thing you are gonna tell me is you arent welding it. It will be a bolted unit :) JR

[tmcmillan5]

Yeah J, they tell me the shocks are ok up side down and this way I can do a little adjusting as needed....I hope. Good point on the beveling I knew I needed to get contact on all three plane but had not thought of beveling. I'll test my Mig wire feed today to see how that works its an old Snap-On made by Century, a body shop model a real work horse. I do have a 275 Lincoln Tig, would I be better of using that over the Mig ?

I have gotten the mounts just about where I want them and trying to think everthing through before I weld them up. All the tubing is 3/16" and the Clading 1/8". We will Tig the Clading on all edges.

I have two 1/2" nutsweld on the backs of the Main base tubing and will be through-bolting the upper mounts just for testing my final heights, when I'm happy with the location we will weld them-up and that may happen much later on once I get the car back together. I just pickup an LS2 swap engine and am a bit overwelmed....that thing has more wires on it than a Christmas Tree...we'll see'

Thanks again, Tony

[JRouche]

I'll test my Mig wire feed today to see how that works its an old Snap-On made by Century, a body shop model a real work horse. I do have a 275 Lincoln Tig, would I be better of using that over the Mig ?

I have gotten the mounts just about where I want them and trying to think everthing through before I weld them up. All the tubing is 3/16" and the Clading 1/8". We will Tig the Clading on all edges.

Thanks again, Tony

Sounds like a good machine. Is it 220vac? If so then Id go with that, TIG will work also. For suspension parts on the car (as assembled and welded on the car) I like MIG mainly because its faster and easier for me to weld. I dont have to use a knee or shoulder to depress the current pedal if Im up under the car. Ive used my toe (side of the foot), ankle, knee, elbow and shoulder to press the TIG pedal while under the tight confines of my car. NOT fun at all. So much easier to just depress the finger on the trigger for the MIG.

And really, the only reason I use TIG is if its SS or aluminum or if I can fit the mild steel weldment on my bench so I can improve my welding skills (Im always looking to improve), Im still really rough with the TIG process.

If it doesnt fit on the bench and is mild steel it gets MIG welded. JR

Oh and speaking of welding under the car with the TIG process. Id kill for a finger current control. Hell!! My middle finger isnt doing much. Id like to put it to work on the current control, just like the foot pedal does. A nice light lever there to control current!! That would be nice to have, but I cant afford that option. I might make one though. Simple enough. And my torch is TOO heavy now with the coolant. But If I used super thin wires (like whats on the ear buds for the ipods and personal stereos now) and used it to actuate solid state relays, Im thinking!!!