Aluminum Modded Front Suspension Wanted

I am gathering parts to make a front suspension from a blank sheet of paper. They will be tubular.

DeMopuar, I assume your aluminum a-arms mount to the chassis with threaded mounts like the one in the photo. If you replace those rubber bushing style mounts with teflon lined rod ends, you'll be able to move the entire upper control arm rearward, between the mounting tabs, to increase your caster. Since a rod end is significantly thinner than a bushing style mount, you'll need to use spacers to make up the distance between the mounting tabs. You increase your caster by using a longer spacer in front of the rod end than behind it.

Dave, what brand is that rod end?

Thanks Dave, I will have to look at the a arm ends where they attach to the chassis. I believe the bushings are installed directly into the a arm, but I am not 100% sure.

Mark

Davdi

Where did you source those wide rod ends? Cost?

Thanks
JT

Those rod ends with the rubber bushings are sold at hot rod shops but I'm unaware of specifics. I'm not even sure you can call it a rod end. I only attached the photo to my posting because I was speculating that's the kind of chassis attachment used in Mark's aluminum a-arms. I've seen Hall's aluminum a-arms and that's exactly what they used for street applications. Hall also sold a competition version of their aluminum a-arms and the only difference was, they used a proper teflon lined rod end or Heim Joint, like the one in the photo below. With proper rod ends, you can get BIG TIME caster because you can move the entire upper A-Arm back in the mount. I suppose you could also use rod ends on the lower A-Arm and move it forward to increase your caster as well (or a combination of the two). Just be careful when playing with caster because it's possible to get way too much caster when you start moving A-Arms backwards and forewards. By the way, don't let anyone tell you that using rod ends to mount your A-Arms will give you a harsh, noisy ride. It's simply not the case when using high quality, teflon lined rod ends.

quote:

....With proper rod ends, you can get BIG TIME caster because you can move the entire upper A-Arm back in the mount. I suppose you could also use rod ends on the lower A-Arm and move it forward to increase your caster as well (or a combination of the two). Just be careful when playing with caster because it's possible to get way too much caster when you start moving A-Arms backwards and forewards.

You're lucky if you can even get 2 degrees caster the average stocker. You need to move the top ball joint rearward about 3/4" on most cars to get in the 6 degree caster range. Since the spindle is located about midway between the upper and lower ball joints this means you move the wheel about 3/8" rearward with just an upper A-arm mod. This can be an issue in big tire cars that are already marginal on tire clearance.

If you move the lower A-Arm ball joint 3/8" forward (than whats possible on typical stockers) and the upper 3/8" rearward you can achieve 6 degrees caster range without biasing the spindle/wheel location rearward, at least with wheels straight, though the additional caster itself will also affect this throughout the steering range.

Many believe you can adjust caster and toe with those rubber bushing type rod ends but its only true on a very limited basis because the angular displacement causes binding in the bushings which are not designed to operate in a deflected position continuously, only intermitently. For true spherical rod ends, this is not a problem when operating within their rated range of angular deflection.

I have both a heim joint and urethane bushing suspended car. Heim joint suspension holds geometry precisely and has superior feel/feedback from smooth surfaced road. They also transmit higher shock loads from pot holes, bumps, and other typical street flaws and are much harder on mounting points because of this. So in some respects street driving can actually be tougher on them. They need to be maintained and can fail ugly if used in place of ball joints without a safety washer. Race cars also have the benefit of being frequently inspected for cracking etc. In the end it's all a matter of how the respective parts are spec'd and designed into the vehicle.

Best,
Kelly

I am going to set up an adjustable jig with threaded mounts and incrimination to I can build tubular a-arms. If they are not within range I can dial the jig a little and whip out another set. If I change rim set I can change the a-arms so to not need spacers.

Problem with rod ends, or what ever you call them, most I have found are English while the bolt in the pantera is metric around a .48" hole. It would be nice to use something common and commercial but it would not be hard to fab your own.

5555 SUSPENSION IN PROGRESS

CHECK OUT PICS ON TUBULAR SUSPENSION BELOW

http://s461.photobucket.com/al...0joint%20suspension/

http://search.yahoo.com/search...UTF8&p=heim%20joints

My Pantera has Ron Siple's upper control arms at all 4 corners, which means the upper control arms pivot on heim joints at all 4 corners. Unfortunately all 4 lower control arms pivot on urethane. I put a lot of miles on my Pantera with this set-up, so I thought I'd offer my thoughts on the subject of heim joints.

I kinda like the heim joints, I don't like urethane. I've been thinkin' about modifying the lower control arms for heim joints too. I don't notice an increase in road harshness on the open road, actually the heim joints reduce friction, and I think the suspension floats better over the kind of bumps you find on freeways and highways. And the steering is very precise. But the heim joints do not isolate road noise, and at slow speeds they transmit the harshness of poorly paved roads into the passenger compartment. When I drove around town in my old hometown of Fillmore I always wished I had all factory rubber in the suspension. (FYI: The heim joints are not lined with rubber or teflon, that sounds like it would make them prone to failure)

So on the open road I like heim joints, but around town I prefer the factory rubber bushings. I want to convert to 100% one or the other, but I haven't made up my mind which way to go. I don't live in Fillmore any longer, the pavement on the roads in Ventura is generally much better.

My car is lowered, the front end is lowered more than the rear, and the steering is very twitchy. I haven't measured it, but I'm sure my caster is in the negative range. I frankly don't care if the caster is ever 6 degrees positive, I just want enough to remove the twitchy-ness from the steering. Its supposed to have 2 degrees and 40 minutes positive caster off the showroom floor, I assume this setting wasn't arrived at randomly, that is probably the amount required to cancel the outer front tires tendency towards positive camber in turns. Therefore to achieve ~3 degrees or more positive caster with my chassis set-up the way it is would make me deliriously happy. Obviously, if I converted the lower control arms to heim joints, I could space the lower control arms all the way forward in the tabs & space the upper control arms all the way rearward in the tabs, and that should be enough.

-G

George, I'm surprised that Ron Siple didn't insist you use teflon lined rod ends because that's all he uses. If you told him you were using non-teflon lined rod ends, he'd tell you to switch to teflon lined immediately. They would eliminate all of that road noise transmission and harshness you're encountering. Also, modifying your lower control arms to use spherical bearings is much easier than modifying them to use rod ends. I'm pretty sure Siple's own Pantera is set-up that way.

FWIW, I use urethane bushings everywhere in our Pantera's front & rear suspension, except for the Koni gas shocks which use steel rod-ends in place of bushings. I noticed an increase in handling precision but no noise increase or ride harshness over stock rubber, which surprised me. But there are various grades of urethane available, and I've not checked the durometer of our bushings.
If you use rod ends/heim joints anywhere in your suspension, I suggest you add rod-end seals- available cheap from Speedway Motors in NE. They are used by dirt track racers on their rod-ends and should increase the operating life of your fully exposed rod-ends on the street.

quote:

Originally posted by David_Nunn:
... I'm surprised that Ron Siple didn't insist you use teflon lined rod ends because that's all he uses ...

The control arms were on 6018 when I purchased it. In other words, they've been on the car quite a while. I am sure they are the heim joints that were supplied with the control arms. Perhaps Ron has not always used teflon lined heim joints ... perhaps they weren't even available when these control arms were purchased.

quote:

Originally posted by Bosswrench:
... If you use rod ends/heim joints anywhere in your suspension, I suggest you add rod-end seals ... should increase the operating life of your fully exposed rod-ends on the street.

I don't know how many miles the previous owner put on the heim joints, but I've put about 20,000 miles on them, and they are still truckin' just fine. It has been my experience that aspersions cast regarding the longevity of heim joints are unfounded. I don't expect them to last as long as rubber, but if they last 1/2 or 1/3 as long, then they are worth their trouble, because the improvement in handling precision is tremendous.

Thankfully the life of the suspension pivots in a Pantera is a little bit easier than the life of the suspension pivots of any open wheeled race car. They stay pretty clean, especially the upper pivots.

-G

Does anyone have additional info on the Ron Siple control arms? Price? Pictures? Contact info? Are they still available?

Thanks,
Ron

Alex, thanks for the photos. Which ball joints did you end up using? Chrysler?

quote:

Originally posted by ALEX:
5555 SUSPENSION IN PROGRESS

CHECK OUT PICS ON TUBULAR SUSPENSION BELOW

http://s461.photobucket.com/al...0joint%20suspension/

quote:

My car is lowered, the front end is lowered more than the rear, and the steering is very twitchy.
-G

Just a thought....Do you have the bump steer shims? Bump steer is a parabolic arch. Shimming the rack does not fix bump steer but it moves the parabolic arch to a range where it is less noticeable in bump. This makes it exaggerated in droop.

Forget what I said, I was thinking in terms of a raised car not a lowered car.

Never the less, lowering the car will get the bump steer past the apex which makes it worse.

If you look at the diagram, the stock suspension is the green arc. As the suspension is compressed you can see the angle change indicated by the arc. The normal suspension travel is located in the yellow circle .

If you add the bumpsteer shim, the main suspension travel crosses the apex of the bump steer arc and seems less of a problem. You can see what happens in droop. It gets worse quick.

If you lower your suspension your travel now falls in red circle so you can see how bump steer is magnified when you lower the suspension:

I forgot to mention, the red line represents the position of your lowered suspension.

I overlapped the 2 diagrams. If you simply lower the car, this is the effect of bump steer in red:

George, Siple has always used teflon lined rod ends for his control arms. He supplies them with or without the rod ends, so I suspect the control arms on your Pantera were supplied without rod ends. I have Siple's full suspension on my Pantera and with teflon lined rod ends, I suffer from none of the road noise transmission and harshness that you're describing.

quote:

Originally posted by comp2:
.... Do you have the bump steer shims? Bump steer is a parabolic arch. Shimming the rack does not fix bump steer but it moves the parabolic arch to a range where it is less noticeable in bump ...

The 1974 Panteras had the relocated rack from the factory. The car is not thrown off by bumps. But the front end has been lowered significantly more than the rear end. It has no positive caster, and due to this it has wonderful turn-in response. If I even think of turning left it goes left. "Twitchy-ness" may be a bad selection of words. I mean even on smooth roads, if I want the car to go straight, I must firmly hold the steering wheel precisely in the straight ahead position. The steering has no self-centering action. I have to concentrate every moment I'm behind the wheel or it will be headed in a direction I don't want to go.

The tires wear wonderfully, its not an alignment issue, it just has no positive caster.

-G

You know another issue is the upright has an 8 degree inclination angle where common uprights such as the MustangII uprights have 11. 8 Degrees is great for a track car but it does not help your self centering.

Ron McCall asked for contact info for Ron Siple.

If Ron is still in business I would like that info as well. I kinda assumed he was retired. David, Julian?

-G

Ron Siple's e-mail address is: Miolnyr@aol.com

I am presently building a GR4 replica ( 4208)with around 600 RWHP, and if some of you wish to test a race application for your alloy or modified a arms , I'd be glad to test it in Spa and give results on the forum, compared to genuine GR4 a arms and sway bars, with Koni racing shocks and Brembo brakes
Pat