Sway bars

[bernardi]

My '55 400 leans noticeably more than new cars on turns. Would a heavier front sway bar and the addition of a rear one correct this? How much would the ride be affected?

[WCraigH]

Interesting you should ask this question at this time. <img src="http://forums.aaca.org/images/graemlins/cool.gif" alt="" /> Adding heavier sway bars to a T-L Packard for better cornering prowess is a project that we've been talking about recently on Eric's Packard Engineering chat. I've done some preliminary measuring and engineering assessment which I'll share here.

The stock T-L front anti-sway bar (gp 13.113, called a "stabilizer rod" by Packard) is 3/4in diameter. For reference, see plate 31G in the parts book. It mounts to each front frame rail at an effective bushing retention width of 33-1/2in between the bushings. The bar ends are attached directly to the front lower control arms with a rubber bushing and C-clip at an effective width of 44-1/2in, 9in behind the front bushing pivot center.

There is no rear anit-sway bar or equivalent. The rear reversed Watts link assembly (Packard calls it a "rear stabilizer" assy) just keeps the rear axle centrally located. See Plate 32B in the parts book and 3rd picture down here.. Because of the central pivot, there's no anti-sway effect. Also, because the rear support arms (gp 15.991) are mounted in rubber bushings, they do not provide much anti-sway resistance either.

As a guide for bar sizing and fitment possibilities, I first checked the Gen-2 (1970-81) Pontiac Firebird, particularly the Trans Am. Since I have a couple of these cars, I took measurements and eyeballed the attachment. The front anti-sway bar from a Trans Am is either 1-1/8in or 1-1/4in diameter. These are 5 and 7 times stiffer in twist than a 3/4in bar (varies to the 4th power of diameter). On the Firebird, the effective retention width between the bushings is 33in and the bushing retainers could easily be bolted to the Packard front frame rails by just drilling some new holes. The bar ends could be attached to the lower control arms by a link assembly (exactly length TBD). The top would be OEM style and the bottom would be some sort of extension flange bolted or welded to the control arm.

When fitted with a front bar as thick as the Firebird's, a rear anti-sway bar becomes mandatory for balanced handling. The Gen-2 Trans Am Firebird used a 3/4in or 7/8in diameter rear anti-sway. It's shape and fitment design does not appear to be easily adaptable to the Packard rear suspension. However, a U-shaped anti-sway bar like used on some recent SUVs appears to be a good possibility. I need to do more exploration and evaluation.

This is not a high priority project for me, but when I start tackling chassis related work on my Panther with the body off, it will be included. I'm not planning on doing any work on my Patrician other than measurements, but I may retrofit the same setup to it once all the details are worked out on my Panther.

You or anybody else is welcome to participate in Eric's P.E. chat to talk further about this interesting project. <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

[Guest imported_PackardV8]

I don't have much body Roll going into a hard curve even at 60 mph here on these snakey Tn. roads. I am using a heavy duty truck shock on front and rear. Checque the 55-56 x-ref for applications.

Craig: i am no suspension expert but i think u'll find that the Firebird with large diameter stabilizer bar is considerably lighter in the front than the Packard. It is my understanding that if we hold the car constant and vary only the engine weight then the stabilizer gets lighter as the engine gets heavier and gets heavier as the engine gets lighter. i.e. The resistance of the stabilizer is inverse to the weight of the engine (or other weight added to the front of the car).

There is also an issue with the angle at which the control arms are affixed to the frame. Packard control arms sweep rearward from the frame while the GM cars since about 64 or 65 advance forward from the frame. Engine position in the Packard is mostly rear of the front spindles while most modern cars have the engine setting directly over the CL between the spindles.

[WCraigH]

Keith, there's a LOT of work to do to figure out the "best" setup. I'm only usinging the Gen-2 Firebird as a starting point. The Packard T-L is quite different from the Firebird in terms of roll center, center of gravity, mass, roll inertia, etc., but not completely out of the ball park.

If you have happy with the handling of your 56 Exec, then don't mess with it. <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

[Guest imported_PackardV8]

Happy with the handling of my Exec????? Yes and no. Considering its a large luxury boat type car never intended for GP racing i'd say its handling is superb. Compared to a Corvette or other racing oriented sports car then there is a lot to be desired. I have noticed that the car is a bit wicked under windy conditions.

[Guest imported_PackardV8]

Craig wrote: "I'm only usinging the Gen-2 Firebird as a starting point. The Packard T-L is quite different from the Firebird in terms..."

What about the large Cadillac as a starting point.

[WCraigH]

Well, I happen to have a couple of Firebirds, but not a Cadillac, so... <img src="http://forums.aaca.org/images/graemlins/tongue.gif" alt="" />

[Guest imported_Speedster]

Craig, Everyone Needs a Caddy or Two! 'Get Cracken' <img src="http://forums.aaca.org/images/graemlins/wink.gif" alt="" /> <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

About a '47 RagTop would be a good start. <img src="http://forums.aaca.org/images/graemlins/cool.gif" alt="" /> I know for a fact that those Slide into the ditch, Very Flat, no Lean at All. <img src="http://forums.aaca.org/images/graemlins/tongue.gif" alt="" />

[WCraigH]

Rick,

Hey, I used to own a 1972 Eldorado, so I'm very familiar with the handling of a Cadillac. <img src="http://forums.aaca.org/images/graemlins/shocked.gif" alt="" /> Gunboats in a gale actually handle better. I think I'll stick with the Firebird Trans Am as a model.

[Joe Block]

I put a 7/8 4130 sway bar on a 67 Mustang for my senior project in college, it sure flat the car out right now, you will want the twin loc rear end to keep the inside tire from spinning as you can lift off the ground If you do get a balance with the front bar. I did upgrade the front bar, but it still corner flat. I believe with a 1-1/4 front bar if would of handle better.

[imported_v12lincoln]

You should check out the suspension from the 40s senior cars, they have sway bars front and rear and a panhard bar which keeps the rear end centered. I have been driving a 40 180 for the last month and it corners as well as my 69 charger with 1 1/4 inch front bar and a 7/8 rear and 1 inch torsion bars. I was surprised at how good the handleing is on thse old Packard, try driving an early lincoln from the 40s then you can complain about poor handling. Great body style but [censored] poor engineering on engine and suspension.