[zookpr]

Yes agreed... those spacers will not allow the rod ends to articulate properly.

Can I ask what brand those items are?

They need to look more like this- http://www.umiperformance.com/images/1017a.jpg

The rod end spacer OD on the ones I use on my car are smaller diameter, on the order of 7/8-1.0 inch diameter! These allow for all of the available rotation freedom. The only limit would be the spacing between the bracket to which they mount. The rod end cannot hit the bracket though since the spacing is sufficiently wide.

 

[UMI Performance]

My second question was why is one of the six heims polished? I first thought it might be a Midwest Control piece, but they all measure out the same. Newer QA1 XM version? UMI, would you know?

Well actually I do think I have the correct answer... and I am pretty sure I am correct here. Over the course of a past few months last year we have noticed the quality of QA1 rod ends to rapidly go down hill. They were coming in with a yellowish tint and the bearings were lose compared to others from the past... some would then come in like they did in the past with the high shine and tight bearing. I contacted QA1 and they didn't really give me answer to why it was happening. I sourced out another rod end brand late last year, the quality of the new rod ends is out standing and the rod ends look great and consistent.

My guess is those are QA1 rod ends because based on your pictures that is exactly what they started looking like for us before we switched brands.

Hope that helps!

 

[bochnak]

Any comments on competition eng rod ends?

http://www.competitionengineering.com/catalog/CategoryDisplay.asp?CatCode=16014

 

[UMI Performance]

Any comments on competition eng rod ends?

http://www.competitionengineering.com/catalog/CategoryDisplay.asp?CatCode=16014

I never used them. When purchasing watch the lad ratings and lining used for the bearing. Some road ends don't use Teflon linings... this is ok for racing but will be noisy on the street.

 

[MALIBRU]

UMI: I replied to your PM. Thanks for confirming my suspicions on the rod end quality.

 

[zookpr]

The rod end spacer OD on the ones I use on my car are smaller diameter, on the order of 7/8-1.0 inch diameter! These allow for all of the available rotation freedom. The only limit would be the spacing between the bracket to which they mount. The rod end cannot hit the bracket though since the spacing is sufficiently wide.

For any one interested, I checked my rod end spacers, they are 7/8 OD and this diameter clears "rod end seals", if you choose to use them to protect the rod end bearing surface and extend the longevity of the rod end for street use.

Rod end seals - http://store.summitracing.com/partdetail.asp?autofilter=1&part=SIT-WS6250&N=700+115&autoview=sku

 

[MALIBRU]

zookpr:
I got to examine those seals last week. Initially looks like a no-brainer add-on to street heims, but they aren't sealed at the bolt head. So if water managed to enter at that point, how would it get out? And if it's covered up, you'll never see it rusting and then ruining the bearing and so on... It makes sense to me that the original intent of these seals was for dirt racing. Of course the seals got inspected after each race.

 

[zookpr]

Adding some sort of seal on a street car is better than just leaving them fully exposed. I don't make them or sell them. Just providing some information that some folks may be interested in. As for sealing around the inner diameter some RTV at assembly will provide seal. I'm not concerned about rust - they don't rust. Just want to keep the road elements off them. For me, I have them on some Caltrac style traction bars on a leaf spring street car. But for others that use rods ends, these things may be holding in the rear like in a Chevelle. Yeah, I know you don't need rod ends on the Caltrac style traction bar - just like you don't need them on a Chevelle 4-link. The single degree of freedom bushed ends that someone posted above are fine.

 

[MALIBRU]

Moving a little closer to finalizing this. A question regarding thread length. Rod ends for 3/4-16 run 1.75". I can bump this to 2.00" to get more engagement.

Many of the exisiting upper double-adjustable arms have this: http://www.midwestcontrol.com/catdisplay_short.php?pg=518

The female depth on 3/4-16 is 1.5". My arm has this adjuster and has an inch threaded in there. Male end is pretty much threaded in with some room for the jam nut.

A 1/4" inch isn't that much of a gain but it's no extra to do it. Going any longer maycause problems on certain bars. Comments?

 

[UMI Performance]

We make our adjusters with 2.00" on the female side and 1.875" on the male threads... we also use 3/4-16" threads. We have never maxed out of adjustment on our applications. The thing I don't like about that Midwest is they are 1018 steel. Our adjusters are machined from 4140 and heat treated.

Hope that helps!
Ryan

 

[bochnak]

I ran some calculation based on mild steel as adjusters.

http://www.engineersedge.com/thread_strength/thread_bolt_stress.htm

From the above using this formula for internal thread, ¾ - 16 on mild steel:

3/4" - 16
En max (in) = 0.7159
Ds min (in) = 0.7391
Le (in) = 0.75
n = 16

(Shear Area) An (in^2) = 1.243948724

Shear stress (yield /2) (psi) = 25,000


Shear area x shear stress = Force


Force to strip (lbs) = 31098.7181


So based on a ¾” thread engagement, it will take 30,000 lbs to strip/pull the threads. If I calculated this correctly, this is about the same strength as to what the rod ends are rated to.

 

[The WidowMaker]

ive heard anywhere from 1x to 1.5x engagement with x=stud diameter.

 

[MALIBRU]

bochnak-
I guess I'm not sure if that Midwest piece is what I have or not but it measures the same. As Emil Faber would have said: "Thread engagement is good." Since you brought up the engineering math, what would be the calculated strength of aluminum lower control arms? Here's a guy using these on a late-model Camaro: http://www.jonaadland.com/Z28/Mods/LCA/AluminumLCAs.html along with a technical commentary on strength. This company offers the same thing: http://pavlockperformance.com/content.php?id=84 I'm going venture a guess that the reason they work on the Camaro is due to the torque arm design. The torque arm manages the twisting forces and the links just keep the rear in the wheelwells.

Well, here's the Coleman Racing 18" bar: http://www.colemanracing.com/catalo...catalog/product_info.php?products_id=35&osCsid=adc9543368133211a0cad7b36c57cd86 It's a turn-key piece: direct-threaded, perfect length, light weight and $17 each.

 

[bochnak]

bochnak-
I guess I'm not sure if that Midwest piece is what I have or not but it measures the same. As Emil Faber would have said: "Thread engagement is good." Since you brought up the engineering math, what would be the calculated strength of aluminum lower control arms? Here's a guy using these on a late-model Camaro: http://www.jonaadland.com/Z28/Mods/LCA/AluminumLCAs.html along with a technical commentary on strength. This company offers the same thing: http://pavlockperformance.com/content.php?id=84 I'm going venture a guess that the reason they work on the Camaro is due to the torque arm design. The torque arm manages the twisting forces and the links just keep the rear in the wheelwells.

Well, here's the Coleman Racing 18" bar: http://www.colemanracing.com/catalo...catalog/product_info.php?products_id=35&osCsid=adc9543368133211a0cad7b36c57cd86 It's a turn-key piece: direct-threaded, perfect length, light weight and $17 each.

I get all my material info at Matweb.com. For shear, just divide the yield by 2.

1018 yield - 53kpsi/2 = 26.5ksi or 26,500 psi shear

6061-T6 - 40ksi/2 = 20,000psi shear

In the initial calc I used 25,000 psi. Re-calc for 26,500 is:

33,000 lbs for .75" engagment for 1018

25,000 lbs for .75" engagment for 6061-T6

http://www.matweb.com/search/DataSheet.aspx?MatGUID=1b8c06d0ca7c456694c7777d9e10be5b&ckck=1



My numbers are very comparable to the link you provided. He does not mention engagement, a variable that is important. Also, a great link, thanks!

 

[bochnak]

ive heard anywhere from 1x to 1.5x engagement with x=stud diameter.

Yes, that is a good rule of thumb. I wanted to actually find hard numbers.

I plan on doing a FEA on the clevis end for the stock arm. I'm trying to find the weakest link, and over design a bit from there.

 

[The WidowMaker]

the pirate4x4 site has a good 4 link excel calculator which allows the use of different materials. it will tell you the safety factor for things like compression (lca), tension (uca), and even failure due to load at the center of the link (not useful unless youre rock crawling with the velle). i went with 1.5" .120 dom, but we already know how f-ing heavy my arms are. at least only half is unsprung weight.

 

[bochnak]

What is the adjustment range on adj. uppers? Stock length for 68-72 is 10.25".

Do lowered cars typically need them longer or shorter for desired pinion angle?

 

[MALIBRU]

**UPDATE**
I’m having Ballistic Fabrication do a custom run of 60 “Ballistic Joints” (aka flex joints) that will specifically fit 64 – 72 A-Body cars that have aftermarket ¾-16 female tubular upper and/or lower rear control arms. These joints replace the rod ends and associated spacers. Ballistic builds their joints for 4X4 applications so they are tough pieces. Owner has no concerns about building a (smaller!) version to fit the Chevelle. Here are the specs:

1.) 100% machined AND forged in the USA!!!
2.) 2.40” mounting width, ½” bolt hole, (OEM specs)
3.) 2” long threaded male shank (up from 1.75” of typical rod end)
4.) Estimated weight to be just under 3lbs
5.) ¾-16 RH & LH threads available
6.) Clear (silver) zinc coated
7.) New Grade 5 zinc jam nut included
8.) Yield @ 208,000 psi, Tensile @ 238,000 psi - Unbelievable

Here’s a link to the details. Also check out the “Image Gallery”: http://www.ballisticfabrication.com/Forged-Chromolly-263quot-Ballistic-Joint_p_1636.html

Above pic shown without zinc. One thing that makes these joints outstanding is their adjustable spherical design. Unlike a rod-end or similar joint product with a c-clip, the Ballistic Joint can be tightened if ever need be. NO SLOPPY RATTLES. In addition, opening the joint for inspection is via a spanner wrench since the side entry has no c-clip or need for proprietary tools.

I also have a bolt kit consisting of 3.5" Grade 8 Armor Coat (aka Ultra Coat) bolts/washers along with a clear zinced Grade 8 conical flange lock nut. See this video demo: http://www.jergensinc.com/Spinner-Grip-Flange-Lock-Nut-Video.aspx Set consists of 4 each of bolts, washers & lock nuts for $15 plus shipping. These bolts should physically look better for longer on driver cars.

Looking at this from a TCO (Total Cost of Ownership) perspective, I believe this joint design is a great deal. My ’70 has boxed factory arms and 8 poly bushings. Being located in the Midwest with marginal roads and steep driveways, I can feel the rear binding up. I will be switching to upper and lower double adjustables with 6 flex joints and OEM rubber bushings in the rearend ears and selling the unused QA1s & spacers that came with the tubular arms. If you want to run a poly bushing at the lower axle, UMI sells part #0013. Since my car is lowered, the double adjustables will allow pinion angle adjustment as well as re-centering the axle in the rear wheelwell.

BTW: These will also fit the G-Body metric cars such as Monte Carlo SS & GN Buicks with a bolt hole mod. To the best of my knowledge, these cars use 12mm bolts, the Chevelle bolt is ½” or 12.7mm so drilling out the factory mount holes would be necessary for these cars.

As I said, this is a custom order with additional costs involved to produce. Production is set to begin next week. Price is $48 each plus shipping. Sold in sets of two. I would likely use USPS Priority Flat Rate to keep shipping costs low. Feel free comment , P.M. me, or email direct at steverenox@yahoo.com

 

[pist0lpete]

Wow those seem to be some really nice pieces. So for $48 you get two joints? Sorry just trying to clarify. The only hesitation I could see people have here would be the availability of a replacement or replacement parts should something happen. I realize these things are basically bullet proof but just thought I'd ask.

 

[MALIBRU]

Neal:
They are $48 each.