Modified stock control arms to accept adj. coilovers

[Benlugchev]

Has anybody ever tried to modify/cut out a section of the center of the upper control arm to let a 2.50" OD coilover pass through it mounted to a custom perch?

Yes I know that buying tubular control arms would be the best route, but im thinking of trying out this method, really nothing to loose, if it doesnt work I just nuy new aftermaket tubular CA's.

My plan is the make a bracket on the lower CA spring perch to accept a hiem joint adj. coilover, cut/modify/remove the stock top spring perch, cut modify/open the middle section of the upper CA enough to let the coilover pass though and make a bracket coming off the frame to accept the top bolt of the coil over.

My measurements show that I can run a 14"-15" eye to eye adjustable coilover, if this all works out.

Depending on how much of the center section of the upper control arm, I would add some gussets or stiffeners to keep its rigidity.

I did alot of searching on this site and only found someone who use a small coil over in place of the stock spring. Really didnt have alot of travel.

Any thoughts yea or nea?

[Benlugchev]

Planning to trip out the upper CA Something like this. (photo stolen from http://67-72chevytrucks.com/vboard/s...d.php?t=441326)

[Benlugchev]

few pics of my own setup. The more I look at it and take measurement, the more I think it will work. But I would love some input on any issues I might face.

[robnolimit]

It's do-able. Oldspowerc10 has done it. Here's a few tips.
1. Trimming the UCA is oK, but you need to put the strength back in it. Forming a length of 3/16" x 1" stock to fit up to the new I.D., and then boxing the arm with 1/8" works great.
2. Move the lower shock mount 'out' on the LCA, to about the inside edge of the bump stop. This will allow a more reasonable spring rate, and reduce the load on the coil over mount bearings.
3. These trucks are heavy, so poly-bushed coil-over mounts are out. Use a bearing mount, a GOOD bearing mount, not the cheapy 1/2 plastic stuff. Also, 5/8" #8 bolts.
4. A 5" travel shock will be close to 14 1/2" at R.H. In a best case scenario, the LCA will be level at R.H. Level from the center of the LCA mount bushing to the center of the ball joint pivit. (not really the arm it self) Get the shocks you are going to use and set the length at 1/2 of the travel, then fab in the mounts.

[Custom 68]

when I did mine I purchasded the uppers since they had more caster built in and modified my lowers. Like Rob said I moved my lowers out as close to the ball joint and also tried to keep them somewhat close to vertical. My upper mount did that and you might need to trim more off the top arms.

[Benlugchev]

Thankyou...awsome advise..you bring up some good points, yes i think boxing in the UCA will be a fairly easy job. So in a perfect world wouldnt I want the top of the shocks to be leaning inward slightly (like i see on my four wheeler) or do i want them closer to vertical? Im looking at the QA1 shocks any reason I should go with different brand? Street/strip use. And when you say bushing ends, im picturing heim joint end, is this correct?

[Damien]

Why do you need to trim the upper control arm? Could you use a stud on the upper mount like most gm cars use and drill a hole in the upper spring pocket.

Bushing ends would be a rubber or poly bushing. Bearing ends use spherical bearings instead of a bushing.

[Benlugchev]

Originally Posted by Damien

Why do you need to trim the upper control arm? Could you use a stud on the upper mount like most gm cars use and drill a hole in the upper spring pocket.

Bushing ends would be a rubber or poly bushing. Bearing ends use spherical bearings instead of a bushing.

I was going to trim the upper spring pocket in order To run a longer shock

Im still not sure if it is best to mount the shocks on a little bit of an angle with the top facing inward or mount them parallel to the frame?

[oldspowered67C10]

Im the guy who did the conversion w/ the short coilovers. I dont see why you couldnt modify the uppers to clear a longer coilover but making the upper mount might be a bit of a challenge. My advise would be to make the lower mounts as close to the lower ball joints as possible. Dont worry about the angle of the coilover, what ever increase in spring rate you run into from running at a angle will be more than offset by the lower mounting point being more outboard.

[Benlugchev]

Originally Posted by oldspowered67C10

Im the guy who did the conversion w/ the short coilovers. I dont see why you couldnt modify the uppers to clear a longer coilover but making the upper mount might be a bit of a challenge. My advise would be to make the lower mounts as close to the lower ball joints as possible. Dont worry about the angle of the coilover, what ever increase in spring rate you run into from running at a angle will be more than offset by the lower mounting point being more outboard.

Thanks oldspowered67C10. I read your thread awhile back and thats where I got the idea to do mine. I agree with keeping the lower mount out towards the ball-joint.

I plan to make the upper mounting brackets off the top part of the frame and box the inner part of the frame for extra support. I will have to trim my inner fender to make this all clear.