rear poly bushings on outboard end of CA

[tube80z]

Double shear on the outboard end doesn't seem necessary. None of the control arm manufacturers have that feature.

 

Ever seen a V8 car hold the brakes and apply some torque against the rears? When you can physically see movement it probably wouldn't hurt to make the installed stiffness of the pieces higher.

 

For a race car using reduced travel I'd mounted the rod ends so that you don't try and move the joint around the ball (bolt is up/down). If you put these in a vice and move them you'll see it takes less force to move them in this direction. And if you're tricky with how you do the mounting on the inside you have the ability to change the rear RC. And if you go down this road I'd look at installing any sway bar directly to the strut so you don't put bending loads on the arms.

 

Cary

[Guest JAMIE T]

Well, orientating the outer rod ends as Cary suggested would be easy in my case, although I don't really think it's needed. My rod ends are very high quality and yes they are stiff to move up and down when they are in you hand, but just the little weight of the control arm is enough to allow them to move freely. Though making the hub/strut assembly would be alittle easier probably doing as Cary suggested. I'm going to think about it alittle today.

 

Also, my arms are built with 1-1/4" DOM, .120" wall. I have the appropriately made inserts welded in the ends for the 3/4" rod ends. They are very stiff, and make the ones made with 1" tubing (Arizona Zcar style) look insuffecient. And since I've seen the Arizona Zcar ones in person and know they work well on V8 cars, I'm alittle with Jon on the double shear thing (Thanks for clearing that up for me BTW, I thought that's what it was but I just wanted to make sure). My inner mounts are double shear.

 

Also, I talked awhile ago with Pete Paraska at one of Mikelly's get togethers about mounting the sway bar links to the strut assembly, and we both feel it's probably the best method.

 

I'm also redesigning my diff. carrier to make it lighter and was thinking about putting multiple pick-ups on the inner side so that RC could be adjusted. I have already drawn those items on CAD. I'm reducing the square tubing to 1-1/2" from the 2" it is now and instead of the tube that runs to the front being welded in, it's going to bolt in.

[Mikelly]

You guys really have my head hurting now... I've got to fabricate a craddle for my Q45 Rear anyway, so why not do something similar to the pics ZlalomZ posted? Hmmm, Might have to go fire up the heater and... Oh wait, I've still got about 100Ft. of wire left to terminate in the thing before I can move on to the next phase!

 

Hmmmm....

Mike

[blueovalz]

In regards to simplicity, has anyone considered a design using ball joints. They are ubiquitous in any racing circle, very stout, and should easily be adapted to a design for the inner bushings. Obviously their degree of movement or swing is less than the sperical bearings, but this large swing is not necessary, and proper orientation could fully eliminate that problem anyway. Just brain-storming here.

[tube80z]

In regards to simplicity, has anyone considered a design using ball joints. They are ubiquitous in any racing circle, very stout, and should easily be adapted to a design for the inner bushings. Obviously their degree of movement or swing is less than the sperical bearings, but this large swing is not necessary, and proper orientation could fully eliminate that problem anyway. Just brain-storming here.

 

Where I built my car they often build hotrods, etc. and what they use is Ford tie-rod ends on street cars. It just so happens a standard bridge reamer has the same taper as the Ford tie-rod end. I have some pics somewhere of all this.

 

They prefer this mehod over rodends for street cars. The Ford end they use costs about 8 dollars wholesale.

 

Cary

[Guest JAMIE T]

Can you find out what size reamer? My catalog shows about 20 bridge reamers.

[ezzzzzzz]

A quik search showed bridge reamers using a 1@10 taper. I don't know if this is standard though. Most speed equipment suppliers sell taper reamers that are 1.5"@12" or 2"@12". I thought most ball joints and tierods used the 1.5"@12". Just an observation...

[zlalomz]

Drsideways runs a vintage Z at VIR with 10 inch slicks. He uses tie rod ends from a Ford F250, Moog # ES2214R for his custom front tubular arms as ball joints.

[blueovalz]

Submitted for your review. I have updated the design very slightly in that I added large washers on both sides of the bearing as a backup guard in case the bearing itself fails. This way the washers will keep the control arm under control if for any reason the bearing or retainer should fail. Also, I added seals to keep debris out of the bearing itself (I found a variety of shaft seals that would fit inside the retainer's ID). 10º of misalignment angle should suffice being the only real misalignment would be for specific applications such a my toe adjuster.

 

[JMortensen]

The control arm already has the inside washer built into it, so you'd just need a large 3/4" washer for the outboard end. I think that is a good idea and very easy to do.

 

As far as seals for the bearings, I have to wonder if that is necessary. I've been running exposed rod ends on the front LCA and TC rods for years, haven't seen damage due to dirt yet. Wouldn't hurt I suppose, but might add a layer of complexity that isn't strictly necessary. I wouldn't do it if it required extra machining on the monoball retainer. If you find some that install with no extra hassle and it makes you more comfortable then go for it.

[heavy85]

This may have been discussed before, but wouldn't you need another degree of freedom in the LCA? Something like you see on most any formula car or what Cary is using on his tube car? Basically an a-arm + a toe link that are not connected. Otherwise when you adjust toe the spacing between the rod ends will change but since the upright is a fixed width you end up bending the rod-ends.

 

Cameron

[JMortensen]

http://forums.hybridz.org/showthread.php?t=89111

We've each built our own toe adjuster that spreads the rear bushing mounts apart. Instead of making the rear part of the arm longer or shorter, we're pivoting it in or out.

 

My concern earlier was that the carrier piece couldn't handle the misalignment, but as Terry pointed out that is not a problem. I was thinking of the angle of the control arm, but the carriers will remain parallel front to rear, and the toe change will occur as a function of the inner bearings, not the outer bearings.

[Mikelly]

Jon, I'm gonna give you props when I copy this whole setup (Refering to your desing in the link above)! The only thing I'll do differently is use some threaded steel blocks I have laying around from the square tube rear control arms I made years ago. I'll extend your square tubing further horizontal from each side to span closer together and just use one of my turnbuckles in the center with a couple of locknuts. I'm gonna use the AZC camber plates and probably go back to a factory control arm in the rear, although I may end up keeping my tubular rear arm, replaced with heim joints on the end as Mike Mileski did.

 

Mikelly

[blueovalz]

This may have been discussed before, but wouldn't you need another degree of freedom in the LCA? Something like you see on most any formula car or what Cary is using on his tube car? Basically an a-arm + a toe link that are not connected. Otherwise when you adjust toe the spacing between the rod ends will change but since the upright is a fixed width you end up bending the rod-ends.

 

Cameron

 

I considered the impact of what you're saying when I was looking at the concept of this design (fixed points for the bearings). At an agressive (1/4") toe change setting (at the inboard bearings), the distance between bearings will change by .00085". On a more conservative setting (1/8") you're obviously looking at a much smaller change of .00021" (Thats with three zeros!).

The fact that the rear bushing is maintained in "sheet" steel uprights whose orientation allows some degree of flex fore and aft makes this very small amount of change inconsequential (my assumption only). If indeed I knew that the bearings were mounted so rigidly that no amount of flex between the two took place (which is the safe way to go), then perhaps a very thin sheet of compressible material (rubber for example) placed between the bearing race and the bearing retainer housing it, on the rear bearing only, (e.g. a rubber washer of such) allowing the race a tiny bit of movement to compensate for the toe changes would prevent premature bearing failure. PFTE lined bearings may also help in this sense in that they offer built-in fexiblility. How much is not known, but certainly better than metal-to-metal.

[heavy85]

http://forums.hybridz.org/showthread.php?t=89111

We've each built our own toe adjuster that spreads the rear bushing mounts apart. Instead of making the rear part of the arm longer or shorter' date=' we're pivoting it in or out.

 

My concern earlier was that the carrier piece couldn't handle the misalignment, but as Terry pointed out that is not a problem. I was thinking of the angle of the control arm, but the carriers will remain parallel front to rear, and the toe change will occur as a function of the inner bearings, not the outer bearings.[/quote']

 

That seems like a good idea with poly bushings taking up any misalignment. I was referring to the pictures in this thread with rod-ends on all four corners of the single piece arm. These are great if you run zero toe but would concern me otherwise .... but then again I tend to like things to be designed in a perfect world with zero misalignment which may not neccessary here.

 

Cameron

[JMortensen]

Jon, I'm gonna give you props when I copy this whole setup (Refering to your desing in the link above)! The only thing I'll do differently is use some threaded steel blocks I have laying around from the square tube rear control arms I made years ago. I'll extend your square tubing further horizontal from each side to span closer together and just use one of my turnbuckles in the center with a couple of locknuts. I'm gonna use the AZC camber plates and probably go back to a factory control arm in the rear, although I may end up keeping my tubular rear arm, replaced with heim joints on the end as Mike Mileski did.

Well coming from you that will be much appreciated! A lot of Jeromio and Terry in there too. I had thought of the same thing you mention with one of your little adjusters in the center. 5/8" threaded tube ends are readily available so it would be easy to just weld them right in. The only reason I ended up with what I ended up with was because I had that old strut tower bar right there, and I looked at those LH and RH thread rod ends and thought that they would work just fine.

 

The only tough part for me as an extreme novice fabricator was aligning the threads so that the turnbuckle would work smoothly. I spent lots of time and ended up figuring out how to clamp both sides in a vise and weld so that they were pointed STRAIGHT at each other after I screwed it up the first time. Then I tapped my own aluminum tap tube for the turnbuckle and it worked, but not smoothly. Apparently I can not tap a hole straight. I finally bit the bullet and ordered a custom turnbuckle from Coleman for the center. It was ~$8 and with it in place everything works perfect.

[tube80z]

The only tough part for me as an extreme novice fabricator was aligning the threads so that the turnbuckle would work smoothly. I spent lots of time and ended up figuring out how to clamp both sides in a vise and weld so that they were pointed STRAIGHT at each other after I screwed it up the first time. Then I tapped my own aluminum tap tube for the turnbuckle and it worked, but not smoothly. Apparently I can not tap a hole straight. I finally bit the bullet and ordered a custom turnbuckle from Coleman for the center. It was ~$8 and with it in place everything works perfect.

 

That can be a tough one. I use a lathe to hold the tube and put tap in the tailstock to get the hole centered and square. I do this after welding though as I haven't yet figured out how to deal with warping from welding a threaded insert. In something like a pushrod (think formula car) this is highly loaded and if not square imparts a bending load on the rod end, which leads to failure.

 

You gotta love all those pre-threaded tubes you can get from coleman. I know I've used a bunch on projects over the years.

 

Cary

[blueovalz]

The only tough part for me as an extreme novice fabricator was aligning the threads so that the turnbuckle would work smoothly

 

I had the same issue, so I assembled all the parts that screwed, bolted, and slid into place, tightened it all down just as it would be on the car, and then tacked everything in place. The only risk here is the splatter getting on the threads, which will gall the you-know-what out of the bolt if you don't find it and remove it before threading a bolt over them.

[Mikelly]

That's exactly what I plan to do with my setup. I'll mock it up, tack it together, check it for smooth operation and then final welding upon install.

 

Any of you guys have an extra rear crossmember I can cut up? I can't believe I dont have one, but while searching for a couple of other things yesterday I was keeping an eye out for that rear horizontal piece and had ZERO luck. The unit I have on the car is powdercoated a pretty blue and I don't think I want to hack it up just yet.

 

Mike

[Guest JAMIE T]

I have a few of them Mike, I'm obviously not using them