Thread: four-bar and coil overs

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Hi:

I recently inherited several cars from my father who, sadly, passed away last fall (fellas, get your ticker checked out). He was only 57 and just beginning to enjoy his retirement after 36 years as a pipefitter. I'm intending on finishing these projects that he started, specifically a 29 ford roadster, which is the subject of my post.

The front suspension was set up with a four-bar and a dropped tube axle suspended by Alden coil-overs. To this, he added a unique panhard arrangement - It consists of a bearing, approximately 1 1/2" in diameter mounted in the center of the backside of the axle. This bearing, in turn, rides inside of peice of vertically positioned channel mounted to the frame.

Has anyone ever seen an arrangement like this? Should I keep it or switch to a more conventional pahard bar? The channel doesn't hang down too far so as to cause any ground clearance issues and it appears to effectively control lateral sway (the car is unfinished and untested).

I hope I explained this well enough to visualize it. If anyone has any pictures of this type of setup, or even of a coil-over, tube axle four-bar setup in general, please post.

Thanks,

DirtyT

I can visualize what you're saying and seems like a good idea. I can see that there will be some binding in the system because the bearing will not always want to go straight up and down like when both front tires encounter the same bump. If the tire on the bearing side encounters a bump and the other tire doesn't, the bearing side tire will want to describe an arc. The bearing in the channel won't let it do this, so the non-bearing side tire will be pulled to the middle of the car against the spring and its mounting, scuffing the tire and generating loading in the spring/mounting as the bearing runs straight up in the channel. Then again, I might be full of it.

There was an accessory sold a long time ago that consisted of a thing that looked like a tuning fork which mounted to the frame cross member that hung down behnd the axle with the two fork prongs facing down. To the axle was mounted a pin that rode in the fork.....it did the same thing as you describe.

As to the roller in the C channel, there must be some minor clearance since, if the roller were tight in the channel, one side of the roller would be rolling with the motion and the other rotating against the motion.

mike in tucson

Mike:

You're absolutely right. There's roughly 1/8" clearance from the bearing to the channel. I really don't know how much lateral sway to expect. My father was reconsidering this set-up though we never really discussed why.

Isn't this essentially what dirt trackers have done for years?

I have seen this set-up before. It works fine. You used to be able to buy them as an aftermarket item.

Here are some reasons that you Father probably was reconsidering:

1 The channel has to be long enough to keep the roller engaged at all points in the suspension travel. When the suspension compresses, the channel now sticks down below the roller and the axle....can it hit the road?

2 With the required side to side play, there can be a noticeable "clunk" when the roller goes from side to side

3 The setup looks kind of clunky on a fenderless car; on a fendered car it doesnt show too bad

mike in tucson

Yep. I have seen this used on the rear of a modified with parallel torsion bars back in the 70's. Wasn't very popular. Would probably rattle quite a bit if used on the street. May eventually bust the bearing. Might give your dad's engineering the benefit of the doubt and try it. Just watch closely.

Thanks guys. I think I'll keep it and see what happens. You don't see coil-overs on a straight axle that much anymore. I know it's not in keeping with the traditional look. I know they used them on altereds for a while back in the day but does anyone recall when they first appeared on the street?