Honest Opinions on LRCAs

[Cutls67]

I am looking to build my own set of lower rear control arms on my 1967 Cutlass. There is alot of them out there to choose from and alot of prices to go along with them. I am planning on building my own with some DOM tubing I have laying around. I am thinking of using the adjustible Currie Johnny Joints on one end and a solid poly bushed opposing end. I was thinking of using a greasable bolt for the solid end to keep the bushing from squeaking, or should I just put a grease zert on the outside and that should work pretty good. I am not saying that I don't like their Currie lower rear control arm, I just think I can build one that I prefer for cheaper. Any opinions would be great.
This is the end I am thinking of using

but with the GM ball center.
Stephan

[CRead01]

I am looking for something similar. I have been thinking about those too.

[Cutls67]

I just couldn't find anything that hit me right without heim joints. So idecided to build my own.

Stephan

[CHILI442]

I've had a set of Global West lower on my '68 for years. They're the ones with the spherical front bearing and del-alum rear bearing. No problems. Have you looked at these, or is it just a cost issue?

[Bryce]

use afco swedged steel tube, they have all lengths in 1" increments. Each side is threaded with LH and RH, makes for easy on car adjustments. Next order some chrome moly rodends with teflon liner (30,000lb load raitng). This will be a cheaper upgrade. $30 a rodend and $15-20 for the tube. the only thing to fab would be the spacers for the chassis and axle mounts,and thats just cuting an aluminum spacer to length.

[Cutls67]

I've had a set of Global West lower on my '68 for years. They're the ones with the spherical front bearing and del-alum rear bearing. No problems. Have you looked at these, or is it just a cost issue?

I guess it is more of the cost issue. And since I have the resources to be able to create what I have in my head I guess I would rather do it that way. Plus I like to say that I did and fabricate all or most the parts on my car.

Stephan

[The Stickman]

Something like these?
http://www.jonaadland.com/Z28/Mods/L...minumLCAs.html

[CRead01]

Something like these?
http://www.jonaadland.com/Z28/Mods/L...minumLCAs.html

great link

[Cutls67]

Something like these?
http://www.jonaadland.com/Z28/Mods/L...minumLCAs.html

I agree nice write-up. I like those better than my original idea. I am going to change my direction now.

Thanks Stephan

[Randy67]

use afco swedged steel tube, they have all lengths in 1" increments. Each side is threaded with LH and RH, makes for easy on car adjustments. Next order some chrome moly rodends with teflon liner (30,000lb load raitng). This will be a cheaper upgrade. $30 a rodend and $15-20 for the tube. the only thing to fab would be the spacers for the chassis and axle mounts,and thats just cuting an aluminum spacer to length.

You can use the old sleeves out of the stock bushings. They fit perfectly into 3/4" helm joints. You can add side spacers if so desired, but mine haven't moved in the year they have been on my car, in both street use and autocross.

[83hurstguy]

Something like these?
http://www.jonaadland.com/Z28/Mods/L...minumLCAs.html

Cool link!

I think the aluminum is going to be good with the rod ends... his numbers check out for a theoretical buckling failure in compression.

However, bending loads go up any time you have binding (aka when using rubber), and then you have a whole other loading scenario. I wouldn't run the aluminum with rubber or poly bushings. Just my .02... I didn't bother running a bending calculation...

[Bryce]

Aluminum seams like a good idea; however, dont forget that aluminum (Al) can work harden. This will happen when Al is used in suspension. Because Al is much more elastic than steel it needs to be made heavier to regain the stiffness. Also, the ultimate loads on the Al tube is fine but do a comparison to the deflection of the Al and steel tube. After the Al is stiff enough to minimize deflections the weight saving is minimal when compared to swedged steel tubes.

This is the reason i went with steel on my custom front suspension.

Now carbon fiber would be trick. Stiffer and stronger than steel but has the catasrophic failure issue.

[Norm Peterson]

Last I knew, Jon Aadland was running a rod end and a hard rubber bushing rod end replacement in each LCA. FWIW, Jon is an engineer at Boeing, and a pretty sharp one from what I've seen on various other forums over the years.

I've never run a bending analysis of LCAs either, though I suspect that as long as you aren't trying to run something really hard like cylindrical Delrin bushings in both LCA ends or use them for spring perches a la the Fox/SN95 Mustangs that Aluminum will be OK. His LCAs did survive a crash that bent the axle . . .

True, the weight savings isn't going to be huge, at least not in any street-driven front engine V8 RWD car. But it is do-able.


Norm

[Marcus SC&C]

It`s hard to find ends with greasable polygraphite bushings in them. Most,if not all are non greasable straight poly. I don`t care much for them due to squeaking/binding issues. If you`re making your own why not just use Johnny Joints on both ends? It`s only a couple bucks more to do it right. The Johnny joints will outlast heims at least 3:1,which makes them a lot cheaper in the long run. All he time they`ll have much better NVH isolation and the exact same range of motion. If you ever wear a set out (you won`t) you can adj. the lash and keep running them or even rebuild them for cheap instead of replacing them. Mark SC&C